2019年4月29日星期一

What’s The Difference Between EPON And GPON Optical Fiber Networks?

by www.fiber-mart.com
EPON and GPON are popular versions of passive optical networks (PONs). These short-haul networks of fiber-optical cable are used for Internet access, voice over Internet protocol (VoIP), and digital TV delivery in metropolitan areas. Other uses include backhaul connections for cellular basestations, Wi-Fi hotspots, and even distributed antenna systems (DAS). The primary differences between them lie in the protocols used for downstream and upstream communications.
 
A PON is a fiber network that only uses fiber and passive components like splitters and combiners rather than active components like amplifiers, repeaters, or shaping circuits. Such networks cost significantly less than those using active components. The main disadvantage is a shorter range of coverage limited by signal strength. While an active optical network (AON) can cover a range to about 100 km (62 miles), a PON is typically limited to fiber cable runs of up to 20 km (12 miles). PONs also are called fiber to the home (FTTH) networks.
 
The term FTTx is used to state how far a fiber run is. In FTTH, x is for home. You may also see it called FTTP or fiber to the premises. Another variation is FTTB for fiber to the building. These three versions define systems where the fiber runs all the way from the service provider to the customer. In other forms, the fiber is not run all the way to the customer. Instead, it is run to an interim node in the neighborhood. This is called FTTN for fiber to the node. Another variation is FTTC, or fiber to the curb. Here too the fiber does not run all the way to the home. FTTC and FTTN networks may use a customer’s unshielded twisted-pair (UTP) copper telephone line to extend the services at lower cost. For example, a fast ADSL line carries the fiber data to the customer’s devices.
 
The typical PON arrangement is a point to multi-point (P2MP) network where a central optical line terminal (OLT) at the service provider’s facility distributes TV or Internet service to as many as 16 to 128 customers per fiber line (see the figure). Optical splitters, passive optical devices that divide a single optical signal into multiple equal but lower-power signals, distribute the signals to users. An optical network unit (ONU) terminates the PON at the customer’s home. The ONU usually communicates with an optical network terminal (ONT), which may be a separate box that connects the PON to TV sets, telephones, computers, or a wireless router. The ONU/ONT may be one device.
 
In the basic method of operation for downstream distribution on one wavelength of light from OLT to ONU/ONT, all customers receive the same data. The ONU recognizes data targeted at each user. For the upstream from ONU to OLT, a time division multiplex (TDM) technique is used where each user is assigned a timeslot on a different wavelength of light. With this arrangement, the splitters act as power combiners. The upstream transmissions, called burst-mode operations, occur at random as a user needs to send data. The system assigns a slot as needed. Because the TDM method involves multiple users on a single transmission, the upstream data rate is always slower than the downstream rate.
 
GPON
 
Over the years, various PON standards have been developed. In the late 1990s, the International Telecommunications Union (ITU) created the APON standard, which used the Asynchronous Transfer Mode (ATM) for long-haul packet transmission. Since ATM is no longer used, a newer version was created called the broadband PON, or BPON. Designated as ITU-T G.983, this standard provided for 622 Mbits/s downstream and 155 Mbits/s upstream.
 
While BPON may still be used in some systems, most current networks use GPON, or Gigabit PON. The ITU-T standard is G.984. It delivers 2.488 Gbits/s downstream and 1.244 Gbits/s upstream.
 
GPON uses optical wavelength division multiplexing (WDM) so a single fiber can be used for both downstream and upstream data. A laser on a wavelength (λ) of 1490 nm transmits downstream data. Upstream data transmits on a wavelength of 1310 nm. If TV is being distributed, a wavelength of 1550 nm is used.
 
While each ONU gets the full downstream rate of 2.488 Gbits/s, GPON uses a time division multiple access (TDMA) format to allocate a specific timeslot to each user. This divides the bandwidth so each user gets a fraction such as 100 Mbits/s depending upon how the service provider allocates it.
 
The upstream rate is less than the maximum because it is shared with other ONUs in a TDMA scheme. The OLT determines the distance and time delay of each subscriber. Then software provides a way to allot timeslots to upstream data for each user.
 
The typical split of a single fiber is 1:32 or 1:64. That means each fiber can serve up to 32 or 64 subscribers. Split ratios up to 1:128 are possible in some systems.
 
As for data format, the GPON packets can handle ATM packets directly. Recall that ATM packages everything in 53-byte packets with 48 for data and 5 for overhead. GPON also uses a generic encapsulation method to carry other protocols. It can encapsulate Ethernet, IP, TCP, UDP, T1/E1, video, VoIP, or other protocols as called for by the data transmission. Minimum packet size is 53 bytes, and the maximum is 1518. AES encryption is used downstream only.
 
The latest version of GPON is a 10-Gigabit version called XGPON, or 10G-PON. As the demand for video and over the top (OTT) TV services has increased, there is an increasing need to boost line rates to handle the massive data of high-definition video. XGPON serves this purpose. The ITU standard is G.987.
 
XGPON’s maximum rate is 10 Gbits/s (9.95328) downstream and 2.5 Gbits/s (2.48832) upstream. Different WDM wavelengths are used, 1577 nm downstream and 1270 nm upstream. This allows 10-Gbit/s service to coexist on the same fiber with standard GPON. Optical split is 1:128, and data formatting is the same as GPON. Maximum range is still 20 km. XGPON is not yet widely implemented but provides an excellent upgrade path for service providers and customers.
 
Most PONs are configured like this. The number of splitters and split levels varies with the vendor and the system. Split ratios are usually 1:32 or 1:64 but could be higher.

Understanding the FTTx Network

by www.fiber-mart.com
FTTx technology plays an important role in providing higher bandwidth for a global network. And FTTx (fiber to the x) architecture is a typical example of substituting copper by fiber in high data rate traffic. According to the different termination places, the common FTTx architectures include FTTH, FTTB, FTTP, FTTC, and FTTN. This article will introduce these architectures respectively.
 
What is FTTx Network?
FTTx also called as fiber to the x, is a collective term for any broadband network architecture using optical fiber to provide all or part of the local loop used for last mile telecommunications.
 
Different FTTx Architectures
FTTP: fiber-to-the-premises, is a loosely used term, which can encompass both FTTH and FTTB or sometimes is used a particular fiber network that includes both homes and businesses. It depends on how the context is used and a specific location of where the fiber terminates. FTTP can offer higher bandwidth than any other broadband services, so operators usually use this technology to provide triple-play services.
 
FTTH: as indicated by the name fiber-to-the-home, fiber from the central office reaches the boundary of the living space, such as a box on the outside wall of a home. Once at the subscriber’s living or working space, the signal may be conveyed throughout the space using any means, such as twisted pair, coaxial pair, wireless, power line communication, or optical fiber. Passive optical networks (PONs) and point-to-point Ethernet are architectures that deliver triple-play services over FTTH networks directly from an operator’s central office.
 
FTTB (fiber to the building) — Fiber terminates at the boundary of the building. A fiber cable in FTTB installation goes to a point on shared property and the other cabling provides the connection to single homes, offices or other spaces. FTTB applications often use active or passive optical networks to distribute signals over a shared fiber optic cable to individual households of offices.
 
FTTC( fiber-to-the-curb or -cabinet), is a telecommunication system where fiber optic cables run directly to a platform near homes or any business environment and serve several customers. Each of these customers has a connection to this platform via coaxial cable or twisted pair. The term “curb” is an abstraction and just as easily means a pole-mounted device or communications closet or shed. Typically any system terminating fiber within 1000 ft (300 m) of the customer premises equipment would be described as FTTC. A perfect deployment example of FTTC is a DLC/NGDLC (digital loop carrier) which provides phone service.
 
FTTN (fiber to the node) — Fiber terminates in a street cabinet, which may be miles away from the customer premises, with the final connections being copper. One of the main benefits of FTTN is the ability to deliver data over more efficient fiber optic lines, rather than other fiber optic lines with the greater speed restriction
 
Conclusion
The advent of the FTTx network is of great significance for people around the world. As it has a higher speed, costs less, and carries more capacity than twisted pair conductor or coaxial cables. 

WHAT IS FTTX OR FIBER TO THE X?

by www.fiber-mart.com
“Fiber to the X” sounds like something really big, like to the “Nth degree.” It is one of the reasons that around 20,000 professionals plan to meet up at CommunicAsia June 26 – 28, 2018 in Singapore to gather info and develop business around it. FTTX is a situation in which all available optical fiber topologies from a telecommunications or cable carrier point to its customers. This is based on (not outside) the location of the fiber termination point. FTTC and FTTN (curb and neighborhood) are similar because the fiber ends outside the building.
 
Whereas, FTTC and FTTN (curb and neighborhood) are a little different. The fiber, in these cases, ends outside a building, not inside the building. FTTH and FTTP (home and premises) mean the same. FTTE (enclosure) refers to a junction box on a floor or in a department in a bigger facility.
 
FTTX, FTTH and FTTP are a must-have because of individuals’ and organizations’ increasing appetite for network, network and more network. The number of voice, image and video files shared on networks is bigger than ever and will continue to increase.
 
FTTx offers a huge amount of bandwidth to meet today’s needs better than ever. It lines up well with the triple play of voice, video and data and now people expect a converged multi-play services environment with huge bandwidth requirements. Apps and services like Hulu, Pluto, Amazon Alexa, WhatsApp, GoDaddy (web hosting, ISP, and DID number provider) and Zoom.us as well as, in general VOIP, RF video, online gaming that enables video and voice while playing, cyber security, and smart everything are depend upon FTTx networks.

2019年4月28日星期日

What Is WDM?

by www.fiber-mart.com
WDM is a technique in fiber optic transmission that enables the use of multiple light wavelengths (or colors) to send data over the same medium. Two or more colors of light can travel on one fiber and several signals can be transmitted in an optical waveguide at differing wavelengths.
 
Early fiber optic transmission systems put information onto strands of glass through simple pulses of light. A light was flashed on and off to represent digital ones and zeros. The actual light could be of almost any wavelength—from roughly 670 nanometers to 1550 nanometers.
 
WDM is a technique in fiber optic transmission for using multiple light wavelengths to send data over the same medium.
 
During the 1980s, fiber optic data communications modems used low-cost LEDs to put near-infrared pulses onto low-cost fiber. As the need for information increased, so did the need for bandwidth. Early SONET systems used 1310 nanometer lasers to deliver 155 Mb/s data streams over very long distances.
 
But this capacity was quickly exhausted. Advances in optoelectronic components allowed the design of systems that simultaneously transmitted multiple wavelengths of light over a single fiber. Multiple high-bit rate data streams of 2.5 Gb/s, 10 Gb/s and, more recently, 40 Gb/s, 100 Gb/s, and 200 Gb/s could be multiplexed through divisions of several wavelengths. Thus, WDM was born.
 
There are two types of WDM today:
 
Coarse WDM (CWDM): WDM systems with fewer than eight active wavelengths per fiber. CWDM is defined by wavelengths. DWDM (see below) is defined in terms of frequencies. DWDM’s tighter wavelength spacing fits more channels onto a single fiber, but cost more to implement and operate.
 
CWDM is for short-range communications, so it employs wide-range frequencies with wavelengths spread far apart. Standardized channel spacing permits room for wavelength drift as lasers heat up and cool down during operation. CWDM is a compact and cost-effective option when spectral efficiency is not an important requirement.
 
Dense WDM (DWDM): DWDM is for systems with more than eight active wavelengths per fiber. DWDM dices spectrum finely, fitting 40-plus channels into the same frequency range used for two CWDM channels.
 
DWDM is designed for long-haul transmission, with wavelengths packed tightly together. Vendors have found various techniques for cramming 40, 88, 96, or 120 wavelengths of fixed spacing into a fiber. When boosted by Erbium Doped-Fiber Amplifiers (EDFAs)—a performance enhancer for high-speed communications—these systems can work over thousands of kilometers. For robust operation of a system with densely packed channels, high-precision filters are required to peel away a specific wavelength without interfering with neighboring wavelengths. DWDM systems must also use precision lasers that operate at a constant temperature to keep channels on target.
 
Ciena’s 6500 Packet-Optical Platform converges packet, Optical Transport Networks (OTNs), and flexible WaveLogic Photonics in a single platform to streamline operations and optimize footprint, power, and capacity. Built for efficient network scaling from the access to the backbone core, it offers the full gamut of CWDM and DWDM solutions, with DWDM solutions ranging from 10 Gb/s to beyond 200 Gb/s.
 
The 6500 has the following advantages:
 
Industry-leading 10G, 40G, 100G, and 200G coherent and control plane capabilities for scale and service differentiation
Hybrid OTN and packet-switching technologies for the most efficient use of network resources
Embedded and discrete software tools that increase programmability, visibility, and control of the optical network
Minimal equipment needed to adapt to a wide variety of requirements, reducing standardization and operational costs
The ability to tailor customer solutions via various chassis, power, and configuration options to maximize operational efficiencies

What You Need to Know When Using 10G over CWDM

by www.fiber-mart.com
Both Passive CWDM and DWDM have been viable solutions in the telecommunications industry, but now, 10G Ethernet is appearing to be the most preferred solution over CWDM, everyone is migrating to the use of 10G Ethernet. This encourages many engineers to figure out how they ought to adjust their new designs to support the transition from 10G to CWDM. If you're one of these designers who's attempting to navigate the transition, the following is what you need to know.
 
Bandwidth Exts are Easier
In past years, designers who want to increase or improve their bandwidth could achieve this easily over a single or duplex mode fiber. During this period, the 1G Ethernet and CWDM solutions were sufficient, and the only limiting element was the power budget of the optical transceiver or the attenuation of your fiber. That it was possible to transmit up to 200 kilometers and utilize just a 1G Ethernet when designers preferred cheap CWDM.
 
Now, many people are considering the 10G Ethernet solutions, and that's why it's necessary to understand how everything will differ when using 10G over CWDM. When intending to migrate to 10G, you need to know the fiber type. For the dispersion and attenuation calculation, every designer need to know the recommended parameters from ITU-T and understanding the vendor and product kind of the fiber could also help. Remember that the physical fiber will work better than the standards claim most of the time.
 
Chromatic dispersion is referred to as the time variance of a single pulse of a signal. To summarize, chromatic dispersion is "the spreading of a light pulse per unit source spectrum width in an optical fibre due to the various group velocities of the different wavelengths composing the source spectrum" or in layman's terms, "the signal is stretched on the fiber transmission path due the dispersion characteristics of the transporting fiber."
 
Chromatic dispersion always exists, but the higher the link speed is, the greater important it becomes. For instance, a wavelength of 1310nm have a 0 ps/nm chromatic dispersion and 5, 25 dB fiber attenuation. In comparison, a wavelength of 1610 nm have a 330 ps/nm chromatic dispersion and a 3,45 dB fiber attenuation.
 
CWDM Over DWDM 10G is Cost-Effective
Designers should bear it in mind that CWDM implementation is more cost effective than passive DWDM infrastructure. These solutions will be more expensive because DWDM lasers cost more. DWDM lasers are essentially DFB lasers which are cooled, however, they are recommended as they contain the longevity that are required in these solutions. If you would like transmit a signal over a large distance, you should think about large metro ring topologies.
 
Though 10GBASE DWDM is more expensive, it's become the first choice because users have started to consider the costs after dividing it over the quantity of customers served. Some customers are more cost-conscious and have lower bandwidth capacity requirements; so, the cheap CWDM infrastructure will make more sense.
 
Remember that the new 10GBASE DWDM services is usually added over the same fiber. This will enhance the support of the initial CWDM infrastructure capacity by 4 times. This is irresistible to many designers.

How to Use OADM in WDM Network ?

by www.fiber-mart.com
OADM is a cost-effective and easy to use passive fiber optic component, which can provide easy to build and grow connectivity environment for WDM network. The optical add-drop multiplexer is one of the key devices to implement such optical signal processing. Use of OADM makes it possible to freely add or drop signals with arbitrary wavelengths over multiplexed optical signals by assigning a wavelength to each destination. In this article, let us introduce how to use OADM in WDM Network.
 
Inside an OADM
A traditional OADM consists of three parts: an optical demultiplexer, an optical multiplexer and between them a method of reconfiguring the paths between the optical demultiplexer, the optical multiplexer and a set of ports for adding and dropping signals. The multiplexer is used to couple two or more wavelengths into the same fiber. Then the reconfiguration can be achieved by a fiber patch panel or by optical switches which direct the wavelengths to the optical multiplexer or to drop ports. The demultiplexer undoes what the multiplexer has done. It separates a multiplicity of wavelengths in fiber and directs them to many fibers.
 
Main Function and Principle of OADM
For an OADM, “Add” refers to the capability of the device to add one or more new wavelength channels to an existing multi-wavelength WDM signal while “drop” refers to drop or remove one or more channels, passing those signals to another network path. The OADM selectively removes (drops) a wavelength from a multiplicity of wavelengths in fiber, and thus from traffic on the particular channel. It then adds in the same direction of data flow the same wavelength, but with different data content. The main function of the OADM function is shown in the following picture. This function is especially used in WDM ring systems as well as in long-haul with drop-add features.
 
How to Connect OADM With WDM MUX/DEMUX
In most cases, OADM is deployed with CWDM or DWDM MUX/DEMUX. It is usually installed in a fiber optic link between two WDM MUX/DEMUXs. The following picture shows a CWDM network using a 1-channel dual fiber OADM between two CWDM MUX/DEMUXs. Signals over 1470 nm are required to be added to and dropped from the dual fiber link. On the OADM, there is usually one port for input and one port for output. The OADM can be regarded as a length of fiber cable in the fiber link. The point is the one or more strand of signals is added or dropped when the light goes through the OADM.
 
Summary
OADM is still evolving, and although these components are relatively small, they are immeasurable in the future. Optical Add-Drop Multiplexer (OADM) is used for multiplexing and routing different channels of fiber into or out of a single fiber. The CWDM OADM is designed to optically add/drop one or multiple CWDM channels into one or two fibers.

2019年4月25日星期四

8 Steps to a Successful Network Cable Infrastructure

by www.fiber-mart.com
n our last blog post we covered the use of balanced STP (Shielded Twisted Pair) and UTP (Unshielded Twisted Pair) to minimize the effects of RFI (Radio Frequency Interference) and EMI (Electromagnetic Interference), along with crosstalk that can take place between wire pairs carrying dissimilar data.
 
Because STP is not as common in today’s networked environment,we’ll reference this discussion on UTP only. We’ll also look at some of the basic issues with respect to the proper installation of UTP, such as Category5e, 6, 6e, and 7. This blog article builds on the information contained in our recent blog articles so be sure to have them handy if you need to review.
 
When we speak of installation with regards to UTP, we’re concerned with the potential for physical changes. Preserving the integrity of our cable(s) will give our network the stability and ongoing support it needs to maintain data rates of 1 Gbps (Cat5e) to 10 Gbps (Cat6, 6e, and 7).
 
The first place to begin in our effort to avoid problems is in how we install them.
 
 
Remove the cable from the spool or pullbox carefully to avoid twisting and kinking. Either one can change the outer dimension of the cable as well as how the conductors twist around one another within it. Kinks can flatten the cable, thus altering its electrical properties. This can adversely affect performance.
 
 
Feed cable trays, sleeves, and conduits with care to avoid damaging the outer sheath. Lack of care can also scrape the insulation from one or more conductors within the jacket causing potential short circuits.
 
 
Be sure not to pull Cat5e, 6, 6e, or 7 with more than 25 lb. of  pulling force for every 4-pair. To exceed this pull force has the potential to change the inter capacitance and inductive properties of the cable twists which can change the way it transports data. It also can snap conductors within it, in which case wire pairs may have to be substituted or a new cable installed.
 
 
Do not exceed a bend radius of 4 x the cable OD (outer dimension). For a  4-pair UTP cable, 10 x the cable OD for a 25-pair backbone cable. Tighter bends can and often will cause changes in the outer dimension of the cable thus causing it to change how it transports data.
 
 
Maintain the tight twist of a UTP cable right up to the point of termination at the jack or plug assembly. This will assist in your effort to maintain the rated specification of the cable.
 
 
When horizontally hanging UTP cable,maintain a maximum of 4 ft. between hangers. Cable sag should be maintained from 4 to 12 inches. When cable sag exceeds 12 inches, there’s a strong chance that the distance between hangers is greater than 4 in. If cable sag is less than 4 inches, it could indicate that the cable may be pulled too tightly.
 
 
When working in return air returns(plenum spaces), use plenum-rated cable because the insulation will not support a flame nor will it emit toxic fumes in the presence of one. Regular non-plenum UTP cable, however, is flammable and it will spread the fire when exposed to it. In addition, it will emit toxic fumes when it burns, and that can cause injury and death.
 
 
When binding cable bundles with wireties, do not pull them too tight as it will pinch the outer cable sheath thus causing potential problems with effective bandwidth and data transmission rates. We will continue to drill down into the installation and care of network cable in my next blog post. Thank you for taking the time to visit our blog.

How to Connect CAT5e and CAT6 Cable

by www.fiber-mart.com
Thus far in past blog articles we’ve focused on the different types of networked infrastructures, the need for UTP (Unshielded Twisted Pair) cable, the various do’s and don’ts associated with the handling and installation; and how UTP, as a balanced line cable, is able to reject RFI  (Radio Frequency Interference) and EMI (Electromagnetic Interference). In this blog article we’ll discuss the termination of UTP at the head end as well as the plugs and jacks at the edge of a network.
 
If you recall, in a past blog post, we discussed where the standards that fuel and control the implementation of network Ethernet cabling and all connected devices come from. If you recall, it is the Electronics Association/Telecommunications Industries Association, also known by its acronym, EIA/TIA. The standard itself that largely controls how devices are wired is the “Commercial Building Telecommunications Standard.”
 
The two primary UTP cable types that commonly are used in computer networks are CAT5e (Category 5e) and CAT6, both of which are balanced lines. They support 10/100 Mbps–up to 1 Gbps and 10 Gbps respectively.
 
If you are looking for cable for security purposes, such as access control and video surveillance, CAT5e will usually do the job. However, if you intend to use it for 4K and 8K, then perhaps CAT6 is a better choice, especially if you want to future-proof your installation. In addition, an important thing to remember is to match the jacks, plugs, patch panels, and other connected devices with others that are rated the same as the cable in use.
 
Making the CAT5e or CAT6 Connection
 
Whether it’s CAT5e or CAT6, there are 4 pairs of conductors that you need to contend with (see illustration). They are:
 
Pair 1: White-Blue/Blue
 
Pair 2: White-Orange/Orange
 
Pair 3: White-Green/Green
 
Pair 4: White-Brown/Brown
 
These four cable pairs, be it CAT5e or CAT6, connect to plugs and jacks according to two connection standards known as T568A and T568B. The latter also is referred to as the AT&T standard.
 
The primary difference between the two is in how positions 1, 2, 3, and 6 are wired (see illustration) with regards to Pairs2 and 3. Using the T568A standard, Pair 2 connects to positions 3 and 6 while Pair  3 connects to positions 1 and 2.Using the AT&T configuration, Pair 2 connects to positions 1 and 2 while Pair 3 uses positions 3 and 6.
 
Does it matter which standard you use? Not really, but once you start using a specific connector configuration on a job,you must continue using it throughout the project. With that said, if you’re adding to an existing installation, you must check the existing connections to determine which configuration that the installer used. Most of the time you will use T568A because it’s used by more techs than the T568B, even AT&T techs.
 
When making a connection using either configuration, remember to do so without unduly untwisting each wire pair. If you do, it will adversely affect the performance of the wire in general. Keep the integrity of the twist as close to the plug, jack, patch panel, etc., as possible to maintain the CAT5e or CAT6 performance.
 
There are four twisted pairs of conductors in a Category 5e or Category 6 UTP (Unshielded Twisted Pair) cable. Although there are other color code standards in place, this is the most common color code configuration in use.
 
There are two methods of connecting Category 5e and Category 6 cable to plugs, jacks, patch bays, and other devices. The T568A is the most commonly used configuration today.

SC Fiber Optic Cable Connector Overview

by www.fiber-mart.com
The SC (Subscriber Connector) style has numerous types of standards recognizing simplex and duplex connectors and adapters. Standards recognizing the SC are FDDI, Fibre Channel, broadband ISDN, ATM and Gigabit Ethernet.
 
As you can tell the SC fiber optic connector has a square style front face and is easily confused with it's smaller relative the LC connector. Let's take a look at some of the advantages of the SC connector.
 
Available as a simplex connector that can be converted to a duplex connector using a clip.
Recommended by a large number of standards.
Offers pull-proof feature.
Great packing density, design reduces the chance of the fiber face damage during connection.
Keyed, low loss, pull and wiggle proof.
Terminated using quick cure epoxy, cleave and crimp and hot melt. 
 
Typically what you'll find at a subscribers location is the bulk horizontal or backbone cable side ends it's run in the facilities telecommunications closet. Your SC connectors will then be managed in a fiber optic enclosure. Let's check out one of my favorites by Corning. 
 
Then the information technology manager, will manage his end using fiber optic patch jumpers that plug into an adapter panel that sits in the fiber optic enclosure. 
 
The SC interface is very commonly used when using media converters to convert copper to fiber, then fiber to copper. The big disadvantage of the SC interface is it does not feature an SFF (Small Form Factor) design.
 
The SFF design commonly uses the LC interface, so if you have an application where the backbone cable needs to be plugged directly into a switch the LC connector will be required. It's still recommended that you use a fiber enclosure, you could just get a fiber jumper with SC on one end and the LC on the other. 

Pulling Fiber Optic Cable - Tips and How To Advice

by www.fiber-mart.com
Pulling fiber optic cable takes a lot of preparation. Without the right tools and knowledge, you can have a big mess on your hands.We'll go over some of the common steps to get you ready to make the pull.
 
1) Measure twice cut once:
First and foremost, get the correct measurement. An easy way to do this would be to fish some pull string through your conduit. Make sure to follow the exact path the fiber will take, end to end. Once your string is all the way through, attach a heavier rope to the end, pull it all the way back and measure your string. Leave the rope in place, you will be using this to pull your fiber through later. (Tip: Always add at least 15ft to the final number. It may cost a little more, but can save you a lot of time and headache if you come up a few feet short. It is also a lot easier to work with the cable if you have some slack, vs a cable that barely reaches).
 
2) Plan your Run:
Buildings- Although it is not necessary to run the fiber through innerduct, many people prefer this to keep it clean and professional looking. If you prefer not to use innerduct, try to keep your pulls as straight as possible. Pulling diagonal is OK, but it will make for a neater appearance if your fiber is running parallel. Get it done right the first time. If someone is unhappy with the appearance, it will take much longer to correct, or re-pull the fiber. (Tip: Never pull around corners, even if you have a helper. You should always pull out the excess fiber to the corner, laying it down in a figure 8 pattern as your doing it. Then flip the whole bundle over and continue to pull on the other side).
 
Conduits- It is important to plan ahead, especially if your planning on pulling the fiber through underground conduit. Just like measuring the fiber, it's very important to get this done right the first time. A general rule of thumb is to use a 1.5" to 2" conduit for the fiber pull. If your running long distances, or using a thick armored fiber, you may want to increase the size to 4". It may also be a good idea to plan ahead and install a second conduit if you plan on future expansion. (Tip: Minimize the number of bends in your run. The fewer bends there are, the easier the pull will go. If you can't get around it, install junction boxes. Also make sure to protect the fiber by putting plastic bushings on the end of the conduit).
 
3) Which Jacket is Right?
Outdoor - Outdoor fiber is used for all outdoor applications (except direct burial). It is flooded with a water resistant gel, which means it can be run in buried conduit. But that also means there is a 50ft limit to being run indoors due to Fire and Safety codes. For direct burial applications, we suggest you use an armored fiber. If you need to suspend the fiber for arial applications, you can buy the fiber with a messenger attached, or buy it separately and and attach it yourself.
 
Indoor - For indoor applications, you need to use a Plenum rated fiber. Plenum fiber complies with all Fire and Safety codes.
 
Indoor/Outdoor - For applications you need to run the fiber indoors and outdoors, you should use an indoor/outdoor rated fiber. This fiber can be run in underground conduit, and doesn't have the 50ft limitation for indoor use. A great all around fiber.
 
4) Pulling the Fiber:
Communication is Key
Pulling fiber almost always requires at least 2 people, so communication is very important. Most fiber runs are a few hundred feet or more, so yelling back and forth isn't an option. What to do? Walkie Talkies can be a great way to keep in touch with the guy at the other end of the cable. Get some with wrist straps or a belt clip so you don't have to constantly pick it up off the ground.
 
Lube it Up
Make sure you properly lube the fiber during the entire run. You will want to start off with a generous coat on the pulling eye and mesh. It would be a good idea to stop from time to time and apply more lube to the fiber as you pull. Always use lubricant that is designed for cable pulling, not just anything off the shelf. If you use the wrong type of lube, it may damage the jacket of your fiber, or other cables around it. It can also clog up the conduit once it dries. Cable pulling lube is designed to resist freezing and clogging.
 
 Use the Right Rope
We recommend using a 1/4" to 1/2" thick pull rope, not pull string. You want to minimize the amount of stretching during your pull and string isn't very good at doing that. Stretching can make pulling your fiber very unstable.
 
Pulling Eye Removal
Never use a knife or blade to remove the pulling eye. This can damage the jacket of the fiber, or worse, the fiber itself. Always use a pair of electrician scissors.
 
Stay up to Code
Honesty is the best policy. The NEC requires that cables used in premises, both commercial and residential, be “listed for the purpose” by a Nationally Recognized Test Laboratory (NRTL, pronounced “nurtle”).Always obey all fire and building codes. Never try to cheat the system just to save a buck, especially when peoples lives are at risk. If plenum rated fiber is required, use plenum rated fiber. It's the right thing to do.
 
5) Pre-Terminated Fiber Optic Cable
The greatest thing to happen since sliced bread. Pre-terminated fiber optic cable assemblies save you time and headache. No need for expensive tools. No need for testing. Our pre-terminated fiber comes to you on a wooden spool, with the connectors already assembled on the fiber. We have the connectors staggered by 1/2" to make it easier to pull through conduit or innerduct. The pulling eye is very strong and wont break on you. Test results are included. It doesn't get any easier than this.

Everything you need to know about fiber optic cables

by www.fiber-mart.com
You’ve started a project to upgrade your network but not sure of what fiber cables you need. Should the cables be single-mode or multi-mode? Is there a specific length or speed needed? All of these questions are great to ask as you prepare your network project and think of future upgrades. Here is everything you need to know about fiber cables including the newest fiber type, OM5.
 
There are primarily two types of fiber optic cabling in the IT space.  Those two types of fiber optic cable are single-mode and multi-mode.  An optical fiber cable is constructed of a core (inner layer), cladding (layer around the core), and jacket (coating around the cladding).  Some layers of protective sheathing are added depending on the application and environment.
 
Single-mode fiber optic cables have a typical core size of 8.3 to 10 microns (in diameter) and a cladding size of 125 microns.  Single-mode cables are normally used in long distance applications with lasers for the optical transmission devices.  OS1 and OS2 are the standard types of single-mode fiber cables.  Both types of fiber cables are built to perform between 1310 nm and 1550 nm, but the OS2 types of cables have a better transmission performance especially over longer distances.
 
Multi-mode fiber optic cables have a typical core size of either 50 microns or 62.5 microns.  They have a cladding size of 125 microns.  Shorter cables distances, especially in data centers, are common uses for multi-mode cables.  Multimode cables are typically manufactured to certain specifications and are classified by Optical Mode categories.  These Optical Modes are known as OM1, OM2, OM3, OM4, and OM5.  OM1 fiber optic cables have a 62.5 micron core size.  All the other OM types listed below have 50 micron core sizes.
 
OM5 is the newest type of multi-mode fiber optic cables, and it is backwards compatible with OM4.  This type of fiber was formerly called Wideband Multi-mode Fiber.  OM5 is constructed to perform outside the normal operating bands of typical multimode cable.  It can support wavelength division multiplexing (WDM) between the wavelengths of 850 nm and 953 nm.  OM5 fiber cabling can transmit at least 4 wavelengths in the 850 nm to 950 nm range.
 
OM4 fiber optic cables are a fairly new type of fiber cables as well.  This color of fiber cables has been used for the past couple of years in Europe.  The reason for this was mainly to distinguish between aqua OM3 cables and aqua OM4 cables.  The new violet color of cables helps with this quick distinction.
 

2019年4月23日星期二

How to clean the Optical Transceiver

by www.fiber-mart.com
We have always emphasized that proper fiber cleaning of connector end-face is very important to ensure the performance of the whole fiber systems. In fact, optical transceiver module is no exception as the contamination of the optical port of a transceiver will also lead to network failure. However, many people overlook the importance of optical transceiver cleaning or do not clean it in a proper way. This is why I want to talk this topic today.
 
When to Clean?
As we know, the connector end-face of fiber jumper is always recommended to clean before connection. But the optical port of the optical transceiver should not need frequent cleaning unless there is a problem because they have less risk of being contaminated compared to jumper. In general, if you have cleaned your connectors, but still experience low-power output from an optical transceiver or a fault signal from your equipment, you should clean the optical port of the transceiver.
 
How to Clean
The best way to clean the optical port of a transceiver is to use the air duster (also called clean dry air) to blow away small dust particles. In addition, lint-free stick/swab is also required for dry cleaning. The detailed cleaning procedure is shown as below:
 
Remove the dust cap from the optical transceiver.
Use an air duster to remove any dirt or particles.
Insert a lint-free stick of the appropriate size (2.5 mm or 1.25 mm) and turn clockwise. Dry cleaning is recommended here. Thus, Don’t use alcohol-based cleaning sticks.
Repeat steps 2 and 3 if necessary.
 
Remove the lint-free stick and reinsert the dust cap to the transceiver. Always keep the dust cap inserted in the transceiver when not in use.
 
Place the transceiver on a clean and static-free area, such as an antistatic mat.
 
Optical ports of transceivers also require proper cleaning to ensure the fiber transmission performance. It is recommended to clean the transceiver port when there is an error on port. Dry cleaning is recommended to use with air duster and lint-free. Moreover, cross contamination should be avoided by always using cleaned jumper. 

What should to do Before Selecting Fiber Cables

by www.fiber-mart.com
Sorting through cables and connectivity options could be a frustrating exercise. It’s hard enough working through the categories and levels of copper networking cables, where most cables end with similar connector. What happens when you start looking at fiber cables? This is where things can definitely get confusing! This article tells you how to select the right kind of fiber cables.
 
Let’s move on off by saying that fiber optic cables can be used in a huge variety of applications, from small office LANs, to data centers, to inter-continental communication links. The information lines that connect between North America and Europe, for example, are constructed with fiber optic cable strung underneath the ocean. Our discussion in this article will focus mainly on the kinds of cables present in those small-scale networks closer to home, and in particular to pre-terminated cables which may be designed for installation, called “patch cords”, “pre-terms”, or any other similar nicknames like fiber patch cables. Prior to you buying, you should make clear the following parameters.
 
Multimode and Single mode
One of the first things to determine when selecting fiber optic cables is the “mode” of fiber that you’ll require. The mode of a fiber cable describes how light beams travel within the fiber cables themselves. It’s important because the two modes aren’t compatible with each other, which means that you can’t substitute one for that other.
 
There’s really not much variety with single mode patch cords, but there’s for multimode. You will find varieties described as OM1, OM2, OM3 and OM4 (OM means the “optical mode”). Basically, these varieties have different capabilities around speed, bandwidth, and distance, and the right type to make use of will be based mostly upon the hardware that is being used with them, and any other fiber the patch cords will be connecting to.
 
Fiber Optic Cable Jackets
Pre-term fiber can be used in a variety of installation environments, and as a result, may need different jacket materials. The standard jacket type is called OFNR, which means “Optical Fiber Non-conductive Riser”. This can be a long-winded way of saying, there’s no metal in it, so it won’t conduct stray electrical current, and it can be installed in a riser application (going in one floor up to the next, for instance). Patch cords are also available with OFNP, or plenum jackets, which are ideal for use in plenum environments for example drop-ceilings or raised floors. Many data centers and server rooms have requirements for plenum-rated cables, and also the local fire codes will invariably have the final say in what jacket type is required. The ultimate choice for jacket type is LSZH, which means “Low Smoke Zero Halogen”, that is a jacket produced from special compounds that provide off very little smoke with no toxic halogenic compounds when burned. Again, seek advice from the neighborhood fire code authority to be certain of the requirements from the installation before making the jacket selection.
 
Simplex and Duplex
Simplex and duplex have only the difference between one fiber or two, and between one connector at each end of the cable, or two connectors each and every end. Duplex patch cords are the most common type, because the method in which most fiber electronics work is they need two fibers to speak. One is used to transmit data signals, and the other receives them. However, sometimes, just one fiber is required, so simplex patch cords may be essential for certain applications. If you aren’t sure, you can always be on the safe side by ordering duplex patch cords, and just one of these two fibers.
 
Fiber Optic Cable Connectors
Remember what we should said at first about copper category cables? No matter what level of twisted pair you were coping with (Cat 5, 5e, etc), you always knew you would be dealing with an 8-position modular RJ-45 plug around the end from the cable. Well, with fiber patch cords, there is a few possibilities when it comes to connectors. The common connector types are FC, LC, SC, ST and MTRJ etc..
 
These are the most typical selections that you will find when choosing amongst patch cords. If you’re able to determine which of these characteristics you need, it is highly likely you will make the right choice when custom fiber optic cables with suitable parameters.

Applications of PLC Splitters

by www.fiber-mart.com
As one of the most important component of PON (Passive Optical Network) system. The market of fiber optic splitters has grown rapidly. The most commonly used type of fiber optic splitters are FBT (Fused Biconical Taper) coupler splitter and PLC (Planar Lightwave Circuit) splitters. But with the maturity and development of the splitter producing process, the cost of PLC splitter is close to FBT splitter’s. Thus, people are more prefered to use PLC splitters instead of FBT splitters because of the better performance of PLC splitters. In today’s market, there are many package type of PLC splitters which are designed for different applications. Today, we talk about something about the package type of PLC splitters.
 
If you are the newbie and first time to buy PLC splitters, you might be curious about the package type of the splitters. Actually, it is not as complex as you think. At present, there are six major package type of PLC splitters according to different applications, i.e. bare fiber splitter, module splitter, rack-mount splitter, fan-out & blockless splitter, Tray splitter and LGX splitter. Of course, these five types are the basic type and there are upgrade version on their foundation offered by different vendors. For example, the following shows us the PLC splitters of Fiberstore with different package types.
 
Bare fiber optical splitter
ABS splitters
Blockless fiber splitter
Fanout splitter
Tray splitter
Rack-mount splitter
LGX splitters
PLC splitter in mini plug-in type
The bare fiber splitter is a type of splitters without connectors. Its input and output are designed with bare fibers (generally use ribbon fiber to output). Bare fiber splitters are used for small spaces that can be easily placed in a formal joint boxes and splice closure. In order to facilitate welding, it does not need specially designed for space reserved.
 
Module splitter, also called cassette splitter, is designed with direct 2.0nm or 3.0nm fiber output. This type of splitter is usually used for patch panel use, such as network cabinet and optical distribution box. It does also need to splice and can better protect the fiber when using. The typical type of module splitter is with ABS box package.
 
Rack-mount splitter is splitter designed in 19 rack mount metal box. In general, it is with fiber optic adapter in the front panel. Rack-mount splitter is used in 19″ ODF (Optical Distribution Frame).
 
Blockless fiber splitter and Fan-out splitter are generally called Mini fiber splitter. The former is designed as direct 900μm buffered fiber output pigtail. The latter is designed with 900μm buffered fiber input and fan-out output which can support higher split ratio. They can both be used in splice closure, optical distribution box, as well as installing in tray and rack-mount splitter box to form the tray splitters or rack-mount splitters. Their advantage is that we have no need to splice.
 
In tray splitter, input fibers and output fibers are preinstalled on a tray which easily fit within ODF, the Cross Connection Cabinet and other optical fiber distribution equipment. The splitters are secured within the trays and the trays are tamper-proof to prevent unwanted entry.
 
LGX splitter is design in a LGX module which is used for LGX chassis application. It is also terminated with adapters and according to different requirements, LGX modules can be inserted into the chassis. In addition, LGX splitter can also installed in rack mount chassis.
 
There’s no one-size-fits-all solution. Thus, so many pacakge type of PLC splitters have been launched to the market to satisfy all kinds of application requirements.