2019年6月16日星期日

Difference bewteen Transceiver and Transmitter

A transmitter can either be a separate piece of electronic equipment or an integrated circuit (IC) within another electronic device. A transmitter generates a radio frequency current applied to the antenna, which in turn radiates radio waves for communication, radar and navigational purposes. The information that is provided to the transmitter is in the form of an electronic signal. This includes audio from a microphone, video from a TV camera, or a digital signal for wireless networking devices. The electronics for a transmitter are simple. They convert an incoming pulse (voltage) into a precise current pulse to drive the source. Different transmitter has different functions. Take the optical transmitter as an example, it consists of the following components: optical source, electrical pulse generator and optical modulator. And the role of it is to convert the electrical signal into optical form, and launch the resulting optical signal into the optical fiber.
 
A transceiver is a device made up of both a receiver and transmitter (the name “transceiver” is actually short for transmitter-receiver) and these two gadgets are in a single module. When no circuitry is common between transmit and receive functions, the device is a transmitter-receiver.
 
Transceivers can be found in radio technology, telephony as well as Ethernet in which transceivers are called Medium Attachment Units (MAUs) in IEEE 802.3 documents and were widely used in 10BASE2 and 10BASE5 Ethernet networks. Fiber-optic gigabit, 10 Gigabit Ethernet, 40 Gigabit Ethernet, and 100 Gigabit Ethernet utilize transceivers known as GBIC, SFP, SFP+, QSFP, XFP, XAUI, CXP, and CFP, among which Cisco SFP is the most popular one. In addition, 1000BASE-T SFP, 10GBASE-T SFP+ and 1000BASE-T copper SFP we mentioned before are all transceivers.
 
Transceiver vs Transmitter
From the above information, we can know that the transmitter can only be used to transmit signals, while the transceiver can both transmit and receive signals. However, many view transceivers as a compromise in terms of performance, functionality, portability and flexibility and if they had any practical value it would be in mobile and portable applications. Transceivers sacrificed some features and performance to gain the smaller size/weight and cost.
 
As for the portability, a transceiver just needs the space of one module, but functions as two different modules. It is easy to be taken on the go. Separate transmitter is not as convenient in some circumstances as it is probably heavier, and takes up more room. But they are advantageous because each could benefit from its own design, without compromising in areas such as I-F frequency choice, conversion frequencies, and audio stages and they are easier to build and work on.
 
As far as the price is concerned, in most cases, a separate transmitter consumes more power. And the price of a single transceiver is much lower than that of a transmitter plus a receiver.Using a common frequency generation/tuning scheme, power supply and other components, it costs less to manufacture a transceiver than a separate transmitter and receiver.As to how to choose from them, the answer depends on your application.
 
Conclusion
You may find many transmitters in you life, like the TV remote control. Although transceiver is not commonly noticed around you, it is actually commonly applied to many places. We can say that it is invisible but versatile. I sincerely hope that this article will help you understand the difference: transceiver vs transmitter, only then, can you use them in the right way.

Fiber Splice Tray and Fiber Enclosure

In the cabinet, we may find many devices and gadgets, such as fiber patch panel, fiber splice tray, fiber enclosure, adapter panel and zip ties which are all little but critical components for cable management. Fiber patch panel, the one we have cued for a lot of times, will give way to fiber splice tray and fiber enclosure, the two subjects that we will introduce today.
 
Fiber Splice Tray Unveil
As we all know, it is usually unavoidable to match splice fiber optic cables with fiber pigtails in data center, which not only demands lower space requirement but also allows a better network performance compared with other fiber optic termination methods.
 
Fiber splice tray, very popular in data center and server room, is a plate to store the fiber cables and splices and prevent them from becoming damaged or being misplaced. Splice trays are necessary for holding and protecting individual fusion splices or mechanical splices. One of the important factors of fiber splice tray is the fiber count that it can hold. Most fiber splice tray can hold up to 24 fiber splices. 12-fiber splice trays are the most commonly used fiber splice tray in fiber optic network.
 
A Closer Look At Fiber Enclosure
It is a box that contains the devices to connect various fiber optic cables. Fiber enclosures can be classified into two configurations, namely rack mount fiber enclosure and wall mount fiber enclosure. And the rack mount fiber enclosure can be further categorized by its height and the design. We have 1U, 2U and 4U choices. The rack mount enclosures come in two flavors. One is the slide-out variety , and the other incorporates a removable lid which requires the user to remove the whole enclosure from the rack to gain internal access.
 
How The Two Coordinate?
Owning solely a fiber splice tray is far more enough. It should be equipped with a device to provide a safe and easy-to-manage environment for fiber splices. Apart from fiber optic splice closure, fiber distribution box and fiber optic enclosure, we can adopt the fiber enclosure displayed today. Fiber splice tray can be installed in fiber enclosure.
 
Here takes the example of fiber splice tray used in FHD fiber enclosure of FS.COM as shown in the following picture. It is a 96-fiber enclosure which has four 24-fiber adapter on the front panel. This 1U fiber enclosure can hold up four 24-fiber splice tray to provide the space for 96 fiber optic splices.
 
Conclusion
As optical fibers are sensitive to pulling, bending and crushing forces, fiber splice tray and fiber enclosure serve as double protections which are used to provide a safe routing and easy-to-manage environment for the fragile optical fiber splices. Attention! Bare fibers without protection tubes should never be exposed outside of a splice tray. It’s our pleasure to provide you with the best solutions.

Do you know Fiber Optical Transponders?

 
As we know, transponder is important in optical fiber communications, it is the element that sends and receives the optical signal from a fiber. A transponder is typically characterized by its data and the maximum distance the signal can travel.
 
Functions of a Fiber Optical Transponder includes:
 
Electrical and optical signals conversion
Serialzation and deserialization
Control and monitoring
Applications of Fiber Optical Transponder
 
Multi-rate, bidirectional fiber transponders convert short-reach 10gb/s and 40 gb/s optical signals to long-reach, single-mode dense wavelength division multiplexing (DWDM) optical interfaces.
 
The modules can be used to enable DWDM applications such as fiber relief, wavelength services, and Metro optical DWDM access overtay on existing optical infrastructure.
 
Supporting dense wavelength multiplexing schemes, fiber optic transponders can expand the useable bandwidth of a single optical fiber to over 300 Gb/s.
 
Transponders also provide a standard line interface for multiple protocols through replaceable 10G small form-factor pluggable (XFP) client-side optics.
 
The data rate and typical protocols transported include synchronous optical network/synchronous digital hierarchy (SONET/SDH) (OC-192 SR1), Gigabit Ethernet (10GBaseS and 10GBaseL), 10G Fibre Channel (10 GFC) and SONET G.709 forward error correction (FEC)(10.709 Gb/s).
 
Fiber optic transponder modules can also support 3R operation (reshape, retime, regenerate) at supported rates.
 
Often, fiber optic transponders are used to for testing interoperability and compatibility. Typical tests and measurements include litter performance, receiver sensitivity as a function of bit error rate (BER), and transmission performance based on path penalty.Some fiber optic transponders are also used to perform transmitter eye measurements.
 
fiber-mart.com Provides Optical Transponders Solution
 
Let’s image that the architecture that can not support automated reconfigureability. Connectivity is provided via a manual Fibre Optic Patch Panel, a patch panel where equipment within an office is connected via fiber cables to one side (typically in the back), and where short patch cables are used on the other side (typically in the front) to manually interconnect the equipment as desired.  There is a point that Fibre Optic Patch Panel, people usually different ports patch panel , for example, 6, 8, 12, 24 port fiber patch panel and they according to different connectors to choose different patch panel, such as LC patch panel,  LC patch panel,  MTP patch panel…
 
optical network
 
The traffic that is being added to or dropped from the optical layer at this node is termed add/drop traffic, the traffic that is transmitting the mode is called through traffic. Regardless of the traffic type, note that all of the traffic entering and exiting the node is processed by a WDM transponder. In the course of converting between a WDM-compatible optical signal and a client optical signal, the transponder processes the signal in the electrical domain. Thus, all traffic enters the node in the optical domain, is converted to the electrical domain, and is returned to the optical domain. This architecture, where all traffic undergoes optical electrical (OEO) conversion, is referred to as the OEO architecture.

2019年6月12日星期三

Differences between EPON and GPON

PON is the abbreviation of passive optical network, which only uses fiber and passive components like fiber splitter and combiner. EPON (Ethernet PON) and GPON (Gigabit PON) are the most important versions of passive optical networks, widely used for Internet access, voice over Internet protocol (VoIP), and digital TV delivery in metropolitan areas. Today we are going to talk about the differences between EPON and GPON.
 
Technology Comparison of EPON and GPON
EPON is based on the Ethernet standard 802.3 that can support the speed of 1.25 Gbit/s in both the downstream and upstream directions. It is well-known as the solution for the “first mile” optical access network. While GPON, based on Gigabit technology, is designated as ITU-T G.983 which can provide for 622 Mbit/s downstream and 155 Mbit/s upstream. GPON is an important approach to enable full service access network. Its requirements were set force by the Full Service Access Network (FASN) group, which was later adopted by ITU-T as the G.984.x standards–an addition to ITU-T recommendation, G.983, which details broadband PON (BPON).
 
As the parts of PON, they have something in common. For example, they both can be accepted as international standards, cover the same network topology methods and FTTx applications, and use WDM (wavelength-division multiplexing) with the same optical frequencies as each other with a third party wavelength; and provide triple-play, Internet Protocol TV (IPTV) and cable TV (CATV) video services.
 
Costs Comparison
No matter in a GPON or in an EPON, the optical line terminal (OLT), optical network unit (ONU) and optical distribution network (ODN) are the indispensable parts, which are the decisive factor of the costs of GPON and EPON deployments.
 
The cost of OLT and ONT is influenced by the ASIC (application specific integrated circuit) and optic module. Recently, the chipsets of GPON are mostly based on FPGA (field-programmable gate array), which is more expensive than the EPON MAC layer ASIC. On the other hand, the optic module’s price of GPON is also higher than EPON’s. When GPON reaches deployment stage, the estimated cost of a GPON OLT is 1.5 to 2 times higher than an EPON OLT, and the estimated cost of a GPON ONT will be 1.2 to 1.5 times higher than an EPON ONT.
 
We all know that the ODN is made up of fiber cable, cabinet, optical splitter, connector, and etc. In the case of transmitting signals to the same number of users, the cost of EPON and GPON would be the same.
 
Summary
Nowadays, since many experts have different opinions on EPON and GPON. Thus, there is no absolute answer to determine which is better. But one thing is clear: PON, which possesses the low cost of passive components, has made great strides driven by the growing demand for faster Internet service and more video. Also, fiber deployments will continue expanding at the expense of copper, as consumer demands for “triple-play” (video, voice and data) grow.

Functions of ONT and OLT in GPON Network

Gigabit passive optical network (GPON) is a point-to-multipoint access mechanism providing end users with the ability to consolidate multiple services onto a single fiber transport network. To realize this technology, many devices are used to support the network, such as optical splitter, ONT, OLT, etc. In this article, we will mainly discuss the functions of ONT and OLT in GPON network.
 
Functions of ONT and OLT
Optical network terminal (ONT) is an optical modem that connects to the termination point with an optical cable. It is used at end user’s premise to connect to the PON network on one side and interface with the user on the other side. Data received from the customer end is sent, aggregated and optimized by the ONT to the upstream OLT. ONT is also known as optical network unit (ONU). ONT is an ITU-T term, while ONU is an IEEE term. They both refer to the user side equipment in GPON network. A small difference between them might be the application locations. ONU can work in different temperature and weather conditions.
 
Optical line terminal (OLT) is the endpoint hardware equipment located in a central office of the PON network. Its basic function is to control the float information in optical distribution network (ODN) to go in both directions. OLT converts the standard signals used by fiber optic service (FiOS) to the frequency and framing used by PON system. In addition, it coordinates the multiplexing between the ONT conversion devices. There are two float directions for OLT system. One is the upstream direction to distribute different types of data and voice traffic from users. The other is the downstream direction which gets data, voice and video traffic from metro network or from a long-haul network and sends it to all ONT modules on the ODN.
 
How to Add or Delete ONT on OLT?
Way to Add ONT on OLT
If the password of an ONT is obtained, you can run the ONT add command to add the ONT offline. However, if the password is unknown, you can run the port portid ont-auto-find command in the GPON mode to enable the ONT auto-find function of the GPON port, and then run the ONT confirm command to confirm the ONT. When the ONT is added, you need to run the display ONT info command to see the current status of ONT. If the control flag is active,
 
Way to Delete ONT on OLT
When you need to delete the ONT on OLT, please use the delete command. Then ONT configuration data is deleted with the deletion of the ONT and the online ONT is forced offline. ONT can’t be deleted when it has been configured with other services. You need to unbind the service first before delete the ONT.
 
How to Troubleshoot ONT?
To troubleshoot the ONT, you should remember that the most important step is to connect your computer directly to the ONT to see if the problem goes away. You can use the Ethernet cable for connection. If the problem still exists, you can reconnect the ONT power supply to clear its internal cache. If the network can not be restored after the above methods, maybe you need to consult professionals for help.
 

Media Converters Provide Cost-effective Soluton

Network complexity, demanding applications, and also the growing number of devices around the network are driving network speeds and bandwidth requirements higher and forcing longer distance requirements within the LANs. However, Media Converters provide solutions to these complaints, utilizing the optical fiber if it is needed, and integrating new equipment into existing cabling infrastructure.
 
What is the Media Converter? Media converter can be a device that functions like a transceiver, converting the electrical signal found in copper UTP network cabling into light waves used in fiber optic cabling. It gives you seamless integration of copper and fiber, and other fiber types in Enterprise LAN networks. Media converter supports numerous protocols, data rates and media types.
 
Fiber optic connectivity is important when the distance between two network devices exceeds the transmission distance of copper cabling. Copper-to-fiber conversion using media converters enables two network devices with copper ports to become connected over extended distances via fiber optic cabling. Media converters provide fiber-to-fiber conversion from multimode fiber to single-mode fiber or single-mode fiber to multimode fiber, and convert a dual fiber link to single fiber using Bi-directional (BIDI) data flow. They can also convert between wavelengths for WDM applications with devices such as WDM multiplexer. Media converters are typically protocol specific and are available to guide a wide variety of network types information rates.
 
For example, the Fiber-To-Fiber Media Converter can offer connectivity between multimode and single-mode fiber, between different power fiber sources and between dual fiber and single-fiber. It extends a multimode network across single-mode fiber with distances as much as 140km. Within this application, two Gigabit Ethernet switches equipped with multimode fiber ports are connected by using a couple of Gigabit Fiber-To-Fiber Media Converters, which convert the multimode fiber to single-mode and let the cross country connection between the switches. Furthermore, they support conversion from one wavelength to a new with all the single mode to multimode converter or multimode to singlemode media converter. These media converters are usually protocol independent and designed for Ethernet,and TDM applications.
 
Media converters do a lot more than convert copper-to-fiber and convert between different fiber types. Media converters for Ethernet networks can support integrated switch technology, and offer the opportunity to perform 10/100M and 10/100/1000M rate switching. Additionally, media converters can support advanced bridge features, including VLAN, QoS prioritization, Port Access Control and Bandwidth Control – that facilitate the deployment of recent data, voice and video to get rid of users. Media converters can offer all these sophisticated switch capabilities in a, cost-effective device.
 
Media converters save CAPEX by enabling interconnection between existing switches, servers, routers and hubs; preserving the investment in legacy equipment. They reduce CAPEX by avoiding the necessity to install new fiber links by enabling WDM technology through wavelength conversion. Media converters also reduce network OPEX by helping troubleshoot and remotely configure network equipment that is at distant locations, not waste time and funds when there is not just a network administrator on the distant location.
 
Media converters are necessary to produce a more reliable and cost-effective network nowadays. So, where are we able to get high quality Media Converters with reasonable price? Visit Fiber Media Converter Solution in fiber-mart.com now.

2019年6月10日星期一

CWDM System Testing Process

With the explosion of CWDM, it is very necessary to formulate a basic testing procedure to certifying and troubleshooting CWDM networks during installation and maintenance. Today, one of the most commonly available test methods is the use of an OTDR or power source and meter, which is capable of testing the most commonly wavelengths, 1310, 1490, 1550 and 1625nm.
 
This article here is based on the pre-connectorized plug and play CWDM systems that allow for connecting to test equipment in the field:
 
In the multiplexing module of a pre-connectorized CWDM system, wavelengths are added to the network through the filters and transmitted through the common port. The transmitted wavelengths enter the COM port in the de-multiplexing module and are dropped. All other wavelengths present at the MUX/DeMux module are went through the express port.
 
Most of today’s OTDRs have expanded capability for testing wavelengths in addition to 1310 and 1550 nm. The OTDR allows partial testing of such system offered in test equipment source. The OTDR allows partial testing of these systems by using the flexibility of pre-connectorized solutions. This is done by switching connections within the CWDM field terminal to allow for testing portions of the non-1310/1550 nm optical paths.
 
To test the 1310nm, the first step is to test the downstream portion of a system at 1310 nm by connecting the OTDR to the 1310 nm input on the CWDM MUX located at the headend. Then switch the test leads over the the upstream side and repeat. Test method is the same for both the downstream and upstream paths.
 
1550 nm testing is performed similarly by switching the test leads to the 1550nm ports. If additional wavelengths are present, you need to follow the procedures below:
 
Using the 1550 nm test wavelength, switch the OTDR connection to the 1550 nm input port on the headend MUX. Have a technician stationed at the field terminal connect the drop cable leg connectors for the 1570 nm customer to the 1550 nm port on the Mux/demux device. What should be noted is that in a play and plug solution this should not require repositioning where the drop cable passes through the OSP terminal. Test the downstream 1570 nm passive link at 1550 nm, and then repeat for the 1570 nm upstream side. When testing is complete, have the technician switch the connections for the 1570 nm drop back to the 1570 nm ports on the field MUX/DeMUX device as shown in Figure 6. Repeat this process for the 1590 nm, 1610 nm drop cables and other wavelengths present. Finally, test the 1550 nm path normally with the 1550 nm drop cable connected to the 1550nm MUX/DeMUX ports.
 
Since the OTDRs is able to test at 1490 or 1625 nm, the drop cables under test could be connected to the EXP port of the module and tested at 1490 or 1625 nm respective wavelength, without having to connect each to the 1550 nm port. Otherwise the procedure is the same.
 
As CWDM network become more and more common the data they carrying has also become critical. The procedure introduced here allows for testing modular pre-connectorized CWDM systems with standard optical test equipments. Relative channel power can be measured with a wide-band fiber optic power meter at the filter outputs or at other points in the network with the aid of a wavelength selective test device or with an optical spectrum analyzer.

Fiber Optic Visual Light Testers

Visual fault locators can be part of OTDR, which is able to locate the breakpoint, bending or cracking of the fiber glass. It can also locate the fault of OTDR dead zone and make fiber identification from one end to the other end. Fiber optic visual fault locators include the pen type, the handheld type and portable visual fault locator. fiber-mart.com also supply a new kind of fiber optic laser tester that can locates fault up to 30km in fiber optic cable.
 
The new visual fault locator fiber optic laser tester 30km is especially designed for field personnel who need an efficient and economical tool for fiber tracking, fiber routing and continuity checking in an optical network during and after installation. It can send fiber testing red light through fiber optic cables, then the breaks or faults in the fiber will refract the light, creating a bright glow around the faulty area. Its pen shape made it very easy to carry, and its Cu-alloy material shell made it sturdy and durable, 2.5nm universal interface make it more attractive. The inspection distance various according to different mode.
 
Features
Easy to check fiber faults with visual red laser light
FC, SC, ST General interface
Sturdy and durable shell
Constant output power
Long inspection distance
Operates in either CW (Continuous wave) or pulse (Both modes are available)
Pen pattern design, convenient for use and carry
Dust-proof design keeps fiber connectors clean
 
Compact in size, light in weight, red laser output, both SM and MM available
 
fiber-mart.com provides enough stock of fiber optic visual light testers which usually be shipped out in a short time, and can be shipped out in 2-4 business days. We offer 1 years warranty for the quality of these products, so customers can place the order with 100% confidence!

How to Terminate Fiber Optic Cables?

Since the late 1970s, various connectors and termination methods have been brought to market. Now in the common case, cables are terminated in two ways: use connectors to make two fibers jointed or to connect the fiber to other network gears; use splices to make a permanent joint between two fibers. And for the former method, you may have little confusions to deal with it. So today this paper will teach you how to terminate by taking an example of fiber optic cable using epoxy.
 
First and foremost, use a proper fiber stripper to carefully slide the jacket off of the fiber to a bare fiber. When you are doing this, be careful that try to avoid breaking the fragile glass fiber. After that, mix the epoxy resin and hardener together and load it into a syringe (If you use the pre-loaded epoxy syringes that are premixed and kept frozen until use, then you don’t do that). And next you must inject the epoxy from the syringe directly into the connector ferrule.
 
Once you have well prepared the epoxy for your connector, you can insert the fiber cable gently into the terminus inside the connector wall and make the bare fiber core stick out about a half an inch from the front of the ferrule. In the case that your cable is jacketed, you may need a crimping tool, such as Sunkit Modular Crimping Tool, to secure the connector to the jacket and strength the cables. Usually two crimp tools would be perfect to this operation.
 
Next, you can just wait the epoxy to cure. During this process, in order to make sure the end of the fiber is not damaged while curing, you should place the connected end in a curing holder. And when this is done, just place the cable and curing holder into a curing oven. But you may worry about “wicking” while curing with a conventional oven. All you have to do to avoid that is to make the end face down, which can ensure the epoxy does not come out of the back side of the connector and compromise the strength member of the cable. Remember: your epoxy curing must in accurate times and temperatures.
 
After the epoxy cured sufficiently, fiber cleaver tools will be in use to cleave the excess protruding fiber core so that it could make the fiber close as much as possible to the ferrule tip in case of fiber twisting. Once cleaved, you have to dispose of the fiber clipping. There is a point you should think highly of that you must use a regular piece of tape to retain your fiber debris, or they will easily end up in your skin or even in your eyes or respiratory system.
 
When you finished the fiber cleaved work, you could need fiber polishing tool to remove the excess epoxy from the ferrule tip and buff out any imperfections on the surface of the fiber. A smooth fiber surface can help to reduce the loss of the light. Last, if you have done all the above work, you may move on to the cleaning of the ferrule and fiber tip. After that, the whole termination procedure is done.

2019年6月9日星期日

Photonic Integrated And High-speed Optical Interconnection Technology

Currently, in the field of active optical devices, high-speed optical communication (40G/100G), broadband access FTTH, 3G and LTE wireless communication, high-speed optical interconnection, chips applied in intelligent Fiber Optic Network, device and module technologies are competing to become the hot spots of development. And the photonic integrated, high-speed optical signal modulation technique, high-speed optical device packaging technology, as the representative of the optical device platform technology are also increasingly being valued by the majority of OC manufacturers.
 
The Technology Development And Breakthrough Of Active Optical Devices
 
To meet the growing demand for bandwidth, while continuing to reduce the capital, operation and maintenance expenses, will continue to be the two main driving force to promote the development of optical communication technology. In order to meet the evolving needs of the system, the development of active optical communication device involves many technologies, however, in recent years there are several technologies deserve special attention, including 40G/100G high speed transmission device and module technology, the next generation fiber access technology, ROF (Radio Over Fiber) components and module technology, optical integration technology, high-speed interconnect optoelectronic components and modules, etc.
 
Optical Integration Technology Is Worth Looking Forward
 
Optical integrated devices due to its low cost, small, easy to large-scale assembly, high work rate, stable performance and other advantages, as early as the 1970s, it caused the world’s attention and research. In the ensuing three decades, with the rapid development of optical waveguide production technology and a variety of fine processing technology, optical integrated devices are heavily into the business, particularly some optical passive components based on Planar Lightwave Circuit (PLC), such as Planar Lightwave Circuit Splitter, arrayed waveguide grating (AWG) and so on, have become hot products in optical communication on the market. In the field of optical active devices, the active integration products are still far from large-scale commercial, but with the successful development of some advanced technologies such as Dispersion Bridge Grating, active devices based on PLC recently made great progress.
 
The develop direction of optical integration technology can be divided into two categories: monolithic and hybrid integration. Monolithic integration refers to the semiconductor or optical crystal substrate, over the same production process, integrating all the components together, such as: PIC and OEIC technology; the hybrid integration refers to through different production processes, making part of the components, then assembled in the semiconductor or optical crystal substrate.
 
Previously, the actual production process of Si-based hybrid integration has been quite complex, but recently, a number of research institutions had improved the traditional hybrid integration technology based on flip, and made great progress. Among them, the most remarkable achievements include two items: The first is the University of California at Santa Barbara, in cooperation with Intel company researched hybrid integrated device based on Wafer level; second is the Ghent University based chip and the wafer hybrid integrated devices.
 
In recent years, the development of optical integration technology, making it quickly became a very worth looking forward platform technology in optic communication, is expected to be widely applied.
 
High-speed Optical Interconnection Technology Beyond Imagination
 
High speed optical interconnection technology is realized by parallel Fiber Transceiver and Ribbon Cable or fiber optic cable. Parallel optical module is based on VCSEL array and PIN array,wavelength of 850nm, suitable for 50/125 μm and 62.5/125 μm multimode fiber. Its electrical interface uses standard MegArray connectors in package, optical interface uses standard MTP/MPO ribbon cable. At present more common parallel optical transceiver module has 4 channels and 12 channels. In the current market, the more common high-speed parallel optical modules include: 4 × 3.125Gb/s (12.5Gb/s) parallel optical module, applications such as high-end computer systems, blade servers short distance interconnection; 12 × 2.725Gb/s (32.7Gb/s) parallel optical module, used in high-end switching equipment as well as backplane connection. Parallel optical module applications are gradually becoming more mature.
 
At present, the rise of applications such as super computer, cloud computing, short-distance high-speed data communication, directly promoting the rapid development of high-pspeed optical interconnection technology, its size of the market and technology development will beyond people’s imagination.

Understanding Fiber Optic Based Light Source

Each piece of active electronics will have a variety of light sources used to transmit over the various types of fiber. The distance and bandwidth will vary with light source and quality of fiber. In most networks, fiber is used for uplink/backbone operations and connecting various buildings together on a campus. The speed and distance are a function of the core, modal bandwidth, grade of fiber and the light source, all discussed previously. Light sources of the fiber light source are offered in a variety of types. Basically there are two types of semiconductor light sources available for fiber optic communication – The LED sources and the laser sources.
 
Using single mode fiber for short distances can cause the receiver to be overwhelmed and an inline attenuator may be needed to introduce attenuation into the channel. With Gigabit to the desktop becoming commonplace, 10Gb/s backbones have also become more common. The SR interfaces are also becoming common in data center applications and even some desktop applications. As you can see, the higher quality fiber (or laser optimized fiber) provides for greater flexibility for a fiber plant installation. Although some variations ( 10GBase-LRM SFP+ and 10GBASE-LX4) support older grades of fiber to distances 220m or greater, the equipment is more costly. In many cases, it is less expensive to upgrade fiber than to purchase the more costly components that also carry increased maintenance costs over time.
 
Light sources of the fiber light source are offered in a variety of types. Basically there are two types of semiconductor light sources available for fiber optic communication – The LED sources and the laser sources.
 
In fiber-optics-based solution design, a bright light source such as a laser sends light through an optical fiber, called laser light source . Along the length of the fiber is an ultraviolet-light-treated region called a “fiber grating.” The grating deflects the light so that it exits perpendicularly to the length of the fiber as a long, expanding rectangle of light. This optical rectangle is then collimated by a cylindrical lens, such that the rectangle illuminates objects of interest at various distances from the source. The bright rectangle allows line scan cameras to sort products at higher speeds with improved accuracy.
 
The laser fiber-based light source combines all the ideal features necessary for accurate and efficient scanning: uniform, intense illumination over a rectangular region; a directional beam that avoids wasting unused light by only illuminating the rectangle; and a “cool” source that does not heat up the objects to be imaged. Currently employed light sources such as tungsten halogen lamps or arrays of light-emitting diodes lack at least one of these features.

The Importance of Reliable Date Cabling

It is hard to imagine a world without the internet as it is so important in the modern business environment. We cannot stress enough the importance of reliable networking cabling. Some recent studies vindicated our evangelical approach to data cabling:
 
Data cabling typically account for less than 10 percent of the total cost of the network infrastructure.
 
The life span of the typical cabling system is upward of 16 years. Cabling is likely the second most long-lived asset or have. The first is the shell of the building.
 
Nearly 70 percent of all network-related problems are due to poor cabling techniques and cable-component problems.
 
Note: If you have installed the proper category or grade of cable, the majority of cabling problems will usually be related to patch cables, connectors, and termination techniques. The permanent portion of the cable such as the part of the wall will not likely be a problem unless it was damaged during installation.
 
Of course, these were facts that we already knew from our own experience. We have spent countless hours troubleshooting cabling systems that were nonstandard, badly designed, poor documented, and shoddily installed. We have seen much money wasted on the installation of additional cabling and cabling infrastructure support that should have been part of the original installation. No mater how you will think about it, cabling is the foundation of the network and it must be reliable!
 
The best way to ensure that your networking needs are met is by checking that the person installing the data cabling is registered with a cable registrar such as ACRS or one of the other five registrars in Australia. You should also make sure that they have the appropriate experience and qualifications in their background, possibly determining this via recommendations or terminations.
 
Another good thing to do is make sure you get two or three quotes in order to create an accurate idea of pricing, as some installed quote ridiculously high-but others quote too low indicating that they are using inferior quality products. Because the installation has been quoted cheaply, does not mean it’s a good idea. Properly priced instances are more likely to have the quality installation products from good fibre optic cable manufacturers.
 
Besides, installation can often have a warranty, usually between five and twenty years. The better the products, the longer the warranty period as a rule.
 
Costs that result from poorly planned and poorly implemented cabling systems can be staggering. One company that had recently moved into a new office space used the existing cabling, which was supposed to be Cat 5 cables. Almost immediately, 100Mbps Ethernet network users reported intermittent problems. These problems include exceptionally slow access time when reading e-mail, saving documents, and using the sales database. Other users reported that applications running under Windows 98 and Windows NT were locking up, which often caused them to have to reboot their PC.
 
After many months of networking annoyances, the company finally had the cable runs tested. Many cables did not even meet the minimum requirements of a Category 5 installations, and other cabling runs were installed and terminated poorly.
 
Contrary to most peoples thinking, faulty cabling cause the type of intermittent problems that the aforementioned company experienced. In additional to being vulnerable to outside interference from eletric-motors, fluorescent lighting, elevators, cellular phones, copies, and microwave ovens, faulty cabling can cause intermittent problems because of other reasons such as substandard components (patch panel, connectors, and cable) and poor installation techniques. LSZH cables are needed some safety advocates such as the plenum space.
 
Robert Metcalfe helped coin the term drop-rate magnification. Drop-rate magnification describes the high degree of network problems caused by dropping a few packets. Medicare estimates that a 1 percent drop in Ethernet packets can correlate to an 80 percent drop in throughput. Modern network protocols that send multiple packets and expect only a single acknowledgement are especially susceptible to drop rate magnification, as a single dropped packet may cause an entire stream of packets to be retransmitted.

2019年6月5日星期三

What Is 40G QSFP+ AOC and it's application

40G AOC, is a type of active optical cable for 40GbE applications that is terminated with 40GBASE-QSFP+ on one end, while on the other end, in addition to QSFP+ connector, it can be terminated with SFP+ connector, LC, SC, FC, and ST connector etc. The 40G QSFP+ AOC is a parallel 40Gbps quad small form factor pluggable (QSFP+) active optical cable, which supplies higher port density and total system cost. The QSFP+ optical modules provide four full-duplex independent transmit and receive channels, each are able of 10Gbps operation 40Gbps aggregate bandwidth of at least 100m multimode fiber. Most DAC assemblies have one module on each end of the cable. But there is a special kind of DAC assembly which may have 3 or 4 modules on one end of the cable. For instance, Cisco QSFP-4X10G-AOC5M compatible QSFP+ to 4SFP+ breakout AOC from fiber-mart has a single QSFP+ module rated for 40-Gbps on one end and four SFP+ modules, each rated for 10-Gbps, on the other end.
 
Applications of 40G QSFP+ AOC
Active Optical Cable (AOC) is used for short-range multi-lane data communication and interconnect applications. It uses electrical-to-optical conversion on the cable ends to improve speed and distance performance of the cable without sacrificing compatibility with standard electrical interfaces. The 40G QSFP+ AOC is a high performance, low power consumption integrated cable for short-range multi-lane data communication and interconnect applications, supporting 40G Ethernet, fiber channel and PCIE. It is compliant with the QSFP MSA and IEEE P802.3ba 40GBASE-SR4. It integrates four data lanes in each direction with 40 Gb/s aggregate bandwidth. Each lane is capable of transmitting data at rates up to 10Gb/s with lengths ranging from one to 100 m. With its benefits, 40G QSFP+ AOC is widely used in many fields as well as promoting the traditional data center to step into optical interconnection.
 
40G QSFP+ AOC vs QSFP+ Optics
Cost: 40G AOCs cost lower than SR4 modules and do not need to use with extra fiber patch cables. For instance, HP 720205-B21 compatible QSFP+ to QSFP+ active optical cables are suitable for very short distances and offer a very cost-effective way to establish a 40-gigabit link between QSFP ports of HP switches within racks and across adjacent racks. Besides, when using 40G AOC, there are no cleanliness issues in optical connector and there is no need to do termination plug and test when troubleshooting, which can help user save more time and money.
 
Insertion Loss & Return Loss: Under the same case of transmission distance, the repeatability and interchangeability performances of SR4 module interface are not good as 40G AOC. What’s more, when different fiber optic patch cables plug into the module, it will have the different insertion loss and return loss. Even for the same module, this issue is existed. Of course, the related metrics such as the testing eye pattern will have no significant changes so long as the variation in and conformed to the scope. In contrast, an AOC with good performance is more stable and has better swing performance than SR4 modules in this situation.
 
fiber-mart's AOC Solutions
fiber-mart’s AOCs achieve high data rates over long reaches which are the best solutions for high-performance computing and storage applications. We supply AOC products such as 10G SFP+ AOCs, 40G QSFP+ AOCs, QSFP+ to 4 SFP+ AOCs, QSFP+ to 8 x LC AOCs and 120G CXP AOCs etc. In addition, custom cables are also available in various lengths. Recently, fiber-mart has cut the price of its direct attach cable (DAC) products in order to offer a more cost-effective high speed transmission solution for the old and new customers.

CWDM Solutions Offered by fiber-mart.com

As broadband has unveiled a new world for subscriber, full of advanced capabilities and faster speeds. Your challenge is to meet their demands without compromising your budget. Because of its distance, speed and bandwidth potential, fiber optics has become the choice for many service providers. Fiber optic connections typically requires two strands of fiber – one for transmitting and one for receiving signals. But how to do if you need to add services or customers, but you’ve exhausted your fiber lines?
 
Thanks to CWDM, coarse wave division multiplexing (CWDM) is a method of combining multiple signals on laser beams at various wavelengths for transmission along fiber optic cables. The number of channels is fewer than in dense wavelength division multiplexing (DWDM) but more than in standard WDM.
 
CWDM has many advantages over DWDM technology in terms of system costs, set-up, maintenance, and scalability. CWDM is a technology which multiplexes multiple optical signals on a single fiber optic stand by using different wavelengths, or colors, of laser light to carry the different signals.
 
Typical CWDM solutions provide 8 wavelengths capacity enabling the transport of 8 client interface over the same fiber. However, the relatively large separation between the CWDM wavelengths allows expansion of the CWDM network with an additional 44 wavelengths with 100GHz spacing utilizing DWDM technology, thus expanding the existing infrastructure capacity and utilizing the same equipment as part of the integrated solution.
 
A single outgoing and incoming wavelength of the existing CWDM infrastructure is used for 8 DWDM channels multiplexing into the original wavelength. DWDM Mux Demux and optical amplifier if needed.
 
The typical CWDM spectrum supports data transport rates of up to 4.25Gbps, CWDM occupies the following ITU channels: 1470nm, 1490nm, 1510nm, 1530nm, 1550nm, 1570nm, 1590nm, and 1610nm, each separated from the other by 20nm. PacketLight can insert into any of the of the 4 CWDM wavelengths (1530nm,1550nm,1570nm and 1590nm), a set of additional 8 wavelength of DWDM separated from each other by only 0.1nm. By doing so up to 4 times, the CWDM network capability can easily expand by up to 28 additional wavelengths.
 
With fiber-mart.com’s compact CWDM solutions, you can receive all of the above benefits and much more (such as integrated amplifiers, protection capabilities, and integration with 3rd party networking devices, etc.) in a cost effective 1 U unit, allowing you to expand as you grown, and utilize your financial as well as physical resources to the maximum. fiber-mart.com provides all the component involved in the process, such CWDM MUX DWMUX, CWDM OADM, even CWDM SFP transceivers.

Typical CWDM Optical Elements and Features

CWDM VS DWDM differ noticeably in the spacing between adjacent wavelengths. DWDM packs many channels into a small usable spectrum, spacing them 1 to 2 nm apart; DWDM systems support a high channel count, but also require expensive cooling equipment and independent lasers and modulators to ensure that adjacent channels do not interfere. CWDM systems, on the other hand, use 10 to 25 nm spacing, with 1300 or 850 nm lasers that drift less than 0.1 nm/c. This low drift eliminates the need for cooling equipment, which, in turn, reduces the total system cost. As a result, CWDM systems support less total bandwidth than DWDM systems, but with 8 to 16 channels, each operating between 155 Mbps and 3.125 Gbps to over 100 Gbps. Typical systems support eight wavelengths, data rates up to 2.5 Gbps per wavelength, and distances up to 50 km.
 
CWDM uses lasers with a wide channel CWDM wavelength spacing. In contrast, DWDM, which is widely used in long-haul networks and some metro core networks (particularly those with large diameters), uses lasers with much narrower wavelength spacing, typically 0.8 or 0.4 nm. The wide channel spacing of CWDM means a lower system cost can be achieved. This lower equipment cost is the result of a lower optical CWDM mux/demux cost (due to wider tolerance on the wavelength stability and bandwidth).
 
CWDM represents significant costs savings-from 25% to 50% at the component level over DWDM, both for equipment OEMs and service provides. CWDM products cost about 3500 dollars per wavelength. Traditional CWDM only scale to about eight wavelengths, but for metro access applications, this may be adaquare. Also, mux demux manufacturer china have found ways to combine CWDM with its regular DWDM blades that allow the systems to scale up to 20 wavelengths. CWDM system architecture can benefit the metro access market because it takes advantage of the inherent natural properties of the optical devices and eliminates the need to artificially control the component characteristics.
 
The typical CWDM optical elements are as follows:
 
CWDM Uncooled Coaxial Lasers: Distributed-feedback multiquantum well (DFB/MQW) lasers are often used in CWDM systems. These lasers typically come in eight wavelengths and feature a 13 nm bandwidth. Wavelength drift is typically only 5 nm under normal office conditions (say, with a 50℃ total temperature delta), making temperature compensation unnecessary. For additional cost savings, the lasers do not require external gratings or other filters to achieve CWDM operation. They are available with or without an integral isolator.
 
CWDM Transmitters/Receives: OC-48 CWDM transmitters typically use an uncooled DFB laser diode and are pigtailed devices in a standard 24-pin DIP package. Six to eight channels are supported (six channels: 1510 to 1610 nm; two additional channels are located at 1470 and at 1490 nm.) The OC-48 receiver typically uses an APD photodetector, has a built-in DC-DC converter, and employs a PLL for clock recovery. Transmission distances of up to 50 km are achievable with these modules.
 
CWDM Multiplexers/Demultiplexer: These come in 4 or 8 channel module, just 4 channel CWDM Multiplexer or 8 channel CWDM Multiplexer, typically use thin -film filters optimized for CWDM applications, with filtering bands matched t other CWDM wavelengths. Filters need to feature low insertion loss and high isolation between adjacent channels.
 
CWDM Optical ADD/Drop Modules (OADMS): These are available in various configurations with one, two, or four add and drop channels using the same thin-film filters as the CWDM mux and demux modules.

2019年6月4日星期二

What is Ribbon Fiber Optic Cable

by www.fiber-mart.com
Ribbon fiber optic cable is a typical fiber optic cable. Unlike beam optical cable, ribbon fiber optic cable is arranged into a strip. Ribbon fiber optic cable is a convenient solution for space and weight problems. The cable ribbons are actually coated optical fibers placed side by side, encapsulated in Mylar tape, similar to a miniature version of wire ribbons used in computer wiring. A single ribbon many contain 4, 8 or 12 optical fibers. There ribbons can be stacked up to 22 high.
 
Because the ribbon contains only coated optical fibers, this type of cable takes up much less space than individually buffered optical fibers. As a result, ribbon cables are denser than any other cable design. They are ideal for applications where limited space is available, such as in an existing conduit that have very little room left for an additional cable.
 
Fiber optic ribbon cable comes in two basic arrangements: Loose tube ribbon cable, fiber ribbons are stacked on top of one another inside a loose-buffered tube. This type of arrangement can hold several hundred fibers in close quaters. The buffer, strength members, and cable jacket carry any strain while the fiber ribbons move freely inside the buffer tube. Jacket ribbon cable looks like a regular tight-buffered cable, but it is enlongated to contain a fiber ribbon. This type of cable typically features a small amount of strength member and a ripcord to tear through the jacket.
 
Ribbon cables is commonly used in urban construction of circle trank cable network, the large capacity and multi-core features facilitate the jumper box crossing task in the local optical area network. Ribbon cables is rarely used in inter-provincial long distance fiber optic trunk cable.
 
Ribbon fiber provides definite size and weight saving, which required the connector, strippers, cleavers, and fusion splicers to be tailored to the ribbon fiber. Below is the simple steps of ribbon fusion splicing:
Ribbon fusion splicer is also called mass fusion splicers, it can splice the entire cable ribbons at on time. Ribbon splicers looks similar to single fiber splicers and work in much the same way, except the ribbons are treated as one assembly, stripped, cleaved and spliced by special tools while held in a special holder. The holder is inserted in a special stripper that uses heat to make stripping easier. After stripping, the holder is placed in a special cleaver that will cleave all 12 fibers at once. Then the fixure with all the cleaved fibers is placed in the splicing machine. When the second ribbon is prepared, the unit is set for automated splicing.
 
fiber-mart, as one of the main fibre optic cable manufacturers provides a compact, efficient, and versatile solution to applications requiring maximum connectivity in a minimum amount of space. Our ribbon cable assemblies provide up to 72 fiber connections in a single point, reducing the physical space and labor requirement, while providing the same bandwidth capacity of a multi-fiber cable with individual fiber/connector terminations per fiber. The advantage of ultilizing ribbon fiber cables resides in the ability to achieve a much higher density in patch panel, cable routing/ducting, and device connection environments, without compromising the quality or quantity of the connection.

What should know Before Selecting CWDM SFP Transceivers

As an extension of wavelength division multiplexing (WDM), coarse wavelength division multiplexing (CWDM) is a technology that multiplexes a number of optical carrier signals onto a single optical fiber through the use of different wavelengths (i.e., colors) of laser light. A CWDM SFP (Small Form-factor Pluggable) transceiver is a hot-swappable input/output device that plugs into an SFP port or slot of a switch or router, linking the port with the fiber-optic network. It is a  kind of optical-electric/electric-optical converter. With the transmitter on one end, the CWDM SFP transceiver takes in and converts the electrical signal into light, after the optical fiber transmission in the fiber cable plant, the receiver end again converts the light signal into electrical signal. The following figure shows the CWDM SFP transceiver in the CWDM system. In the figure, TX represents “transmit”, RX represents “receive”. Being a kind of compact optical transceiver, CWDM SFP transceiver is widely used in optical communications for both telecommunication and data communication. It is designed for operations in Metro Access Rings and Point-to-Point networks using Synchronous Optical Network (SONET), SDH (Synchronous Digital Hierarchy), Gigabit Ethernet and Fibre Channel networking equipment.
 
Three Components of CWDM SFP Transceivers
The CWDM SFP transceiver consists of an un-cooled CWDM Distributed Feed Back (DFB) laser transmitter, a PIN photodiode integrated with a Trans-impedance Preamplifier (TIA) and a Microprogrammed Control Unit (MCU). The DFB laser used in the CWDM SFP transceiver transmitter is a 18 CWDM DFB wavelengths laser. It is well suited for high capacity reverse traffic. Obeying the standard diode equation for low frequency signals, The PIN photodiode has a 80km transmission distance. And the MCU is a high-speed, executive, input-output (I/O) processor and interrupt handler for the NRL Signal Processing Element (SPE).
 
Advantages of CWDM SFP transceivers
Using existing fiber connections efficiently through the adoption of active wavelength multiplexing, CWDM SFP transceivers have improved the designs of telecommunications devices and other technologies. Here are some advantages of CWDM SFP transceivers:
 
Scalability and Flexibility—CWDM SFP transceivers can support multiple channels. It means that more channels can be activated as demand increases. CWDM SFP transceivers have a wide variety of network configurations that range from the meshed-ring configurations to the multi-channel point-to-point. In point-to-point configurations, the two endpoints will connect directly through a fiber link, allowing users to add or delete as many as eight channels at a time.
Low Risks in Investment—Most CDWM SFP transceivers have a low failure rate, which is less likely to be the reason why the user’s solution fails. It helps enterprises increase the bandwidth of the Gigabit Ethernet optical infrastructure without adding any additional fiber strands and can also be used in conjunction with other SFP devices on the same platform. Thus the user will be able to re-invest the capital saved by avoiding prematurely failed devices.
 
Selecting a Right CWDM SFP Transceiver
There are many kinds of CWDM SFP transceivers in the market. Their wavelengths are available from 1270 nm to 1610 nm, with each step 20 nm. Different CDWM SFP transceivers have different color codes, distances, date rates and laser operating wavelengths. For example, the CWDM-SFP-1470, which is colored gray, is one of Cisco CWDM SFP. It is a CWDM SFP transceiver that rates for distances up to 80 km and a maximum bandwidth of 1Gbps, operating at 1470nm wavelength. Customers may choose a CWDM SFP transceiver in accordance with their actual needs.
 
Applied to the access layer of Metropolitan Area Network (MAN), CWDM is a low-cost WDM transmission technology. fiber-mart.com provides the aforesaid CWDM-SFP-1470 and other types of CWDM SFP transceivers, which are convenient and cost-effective solution for the adoption of Gigabit Ethernet and Fibre Channel in campus, data center, and metropolitan-area access networks.