Which Kind of Single-mode Fiber Should You Choose?

Fiber optic terminology often seem to be a bit like alphabet soup, but I’m sure you already knew that. What you may not know is how to decide on the best single-mode fiber for your particular fiber optic network. Each type of single-mode fiber has its own area of application and the evolution of these optical fiber specifications reflects the evolution of transmission system technology from the earliest installation of single-mode optical fiber until today. In this post, I may explain a bit more about the differences between the specifications of the G.65x series of single-mode optical fiber families.

As is know to all, multimode fiber is usually divided into OM1, OM2, OM3 and OM4. But the types of single-mode fiber is much more complex. There are mainly two specifications of single-mode optical fiber. One is the ITU-T G.65x series, and the other is IEC 60793-2-50 (published as BS EN 60793-2-50). This purpose of this article is to introduce ITU-T G.65x series single-mode fiber.

Name	Type
ITU-T G.652	ITU-T G.652.A, ITU-T G.652.B, ITU-T G.652.C, ITU-T G.652.D
ITU-T G.653	ITU-T G.653.A, ITU-T G.653.B
ITU-T G.654	ITU-T G.654.A, ITU-T G.654.B, ITU-T G.654.C
ITU-T G.655	ITU-T G.655.A, ITU-T G.655.B, ITU-T G.655.C, ITU-T G.655.D, ITU-T G.655.E
ITU-T G.656	ITU-T G.656
ITU-T G.657	ITU-T G.657.A, ITU-T G.657.B, ITU-T G.657.C, ITU-T G.657.D

G.652

The ITU-T G.652 fiber is also known as standard SMF (single-mode fiber) and is the most commonly deployed fiber. It comes in four variants (A, B, C, D). A and B have a water peak. C and D eliminate the water peak for full spectrum operation. The G.652.A and G.652.B fibers are designed to have a zero-dispersion wavelength near 1310 nm, therefore they are optimized for operation in the 1310-nm band. They can also operate in the 1550-nm band, but it is not optimized for this region due to the high dispersion. These optical fibers are usually used within LAN, MAN and access network systems. The more recent variants (G.652.C and G.652.D) feature a reduced water peak that allows them to be used in the wavelength region between 1310 nm and 1550 nm supporting Coarse Wavelength Division Multiplexed (CWDM) transmission.

G.653

G.653 fiber was developed to address this conflict between best bandwidth at one wavelength and lowest loss at another. It uses a more complex structure in the core region and a very small core area, and the wavelength of zero chromatic dispersion was shifted up to 1550 nm to coincide with the lowest losses in the fiber. Therefore, G.653 fiber is also called dispersion-shifted fiber (DSF). G.653 has a reduced core size, which is optimized for long-haul single-mode transmission systems using erbium-doped fiber amplifiers (EDFA). However, its high power concentration in the fiber core may generate nonlinear effects. One of the most troublesome, four-wave mixing (FWM), occurs in the CWDM system with zero chromatic dispersion, causing unacceptable crosstalk and interference between channels.

G.654

The G.654 specification uses a larger core size made from pure silica to achieve the same long-haul performance with low attenuation in the 1550-nm band. It usually also has high chromatic dispersion at 1550 nm, but is not designed to operate at 1310 nm at all. G.654 fiber can handle higher power levels between 1500 nm and 1600 nm, which is mainly designed for extended long-haul undersea applications.

G.655

G.655 is known as non-zero dispersion-shifted fiber (NZDSF). It has a small, controlled amount of chromatic dispersion in the C-band (1530-1560 nm), where amplifiers work best, and has a larger core area than G.653 fiber. NZDSF fiber overcomes problems associated with four-wave mixing and other nonlinear effects by moving the zero-dispersion wavelength outside the 1550-nm operating window. There are two types of NZDSF, known as (-D)NZDSF and (+D)NZDSF. They have respectively a negative and positive slope versus wavelength. Following picture depicts the dispersion properties of the four main single-mode fiber types. The typical chromatic dispersion of a G.652 compliant fiber is 17ps/nm/km. G.655 fibers were mainly used to support long-haul systems that use DWDM transmission.

G.656

As well as fibers that work well across a range of wavelengths, some are designed to work best at specific wavelengths. This is the G.656, which is also called Medium Dispersion Fiber (MDF). It is designed for local access and long haul fiber that performs well at 1460 nm and 1625 nm. This kind of fiber was developed to support long-haul systems that use CWDM and DWDM transmission over the specified wavelength range. And at the same time, it allow the easier deployment of CWDM in metropolitan areas, and increase the capacity of fiber in DWDM systems.

G.657

G.657 optical fibers are intended to be compatible with the G.652 optical fibers but have differing bend sensitivity performance. It is designed to allow fibers to bend, without affecting performance. This is achieved through an optical trench that reflects stray light back into the core, rather than it being lost in the cladding, enabling greater bending of the fiber. As we all know, in cable TV and FTTH industries, it is hard to control bend radius in the field. G.657 is the latest standard for FTTH applications, and, along with G.652 is the most commonly used in last drop fiber networks.

Choosing the right one for your project can be vital in terms of performance, cost and reliability of the optic fiber assemblies, such as fiber jumper or fiber optic cable. Different kind of single-mode fiber has different application. Since G.657 is compatible with the G.652, some planners and installers are usually likely to come across them. In fact, G657 has a larger bend radius than G.652, which is especially suitable for FTTH applications. And due to problems of G.643 being used in WDM system, it is now rarely deployed, being superseded by G.655. G.654 is mainly used in subsea application.

Originally published at http://www.fs.com/blog

3 Reasons Why You Should Use HP JD119B Compatible SFPs

As more and more companies are moving towards fiber optic networking, one question we often hear is "Will we be able to use our existing equipment with the new wiring?" In most cases, the answer to this is yes! If you're using HP networking equipment with SFP/SFP+ interfaces, you can simply buy some plug-and-play transceivers which change the network connectors to match your new fiber runs as long as the transceivers are compatible with the originally branded devices.

One common issue when using optical transceiver is that many vendors charge too much for their transceivers, assuming companies will simply pay without doing their homework. But if you're looking for 1000BASE-LX transceivers for your HP hardware, you can turn to FS.COM for their own brand of fully HP-compatible transceivers and get a lot more value with a lot less money.

Three Reasons To Turn To FS.COM For Your HP JD119B SFPs

1. 100% Compatibility

One thing a lot of people haven’t realized about optical networking equipment is that there are only a handful of factories in the world which are certified to produce it. Every store that sells top-grade SFP transceivers is getting them from the same few vendors. And FS.COM uses them too.

FS.COM HP compatible JD119B 1000Base-LX transceivers are fully MSA-compliant, so they adhere to all relevant standards for optical equipment. They also come pre-loaded with the compatible coding on the EPROM chip so that your HP hardware will recognize it as soon as it's plugged in. Not only the 1000Base-LX transceivers, all the other compatible transceivers from FS.COM are the same. For example, if you plug a Juniper Networks EX-SFP-10GE-LR compatible 10GBASE-LR SFP+ into the Juniper Networks switches, the switches will report them as "official" when checking the transceiver status.

2. Excellent Support

With most name-brand SFP transceivers, you get a minimal warranty. Usually it's a year at most, and often as low as 90 days. Despite how much you pay for transceivers from the major vendors, they simply don't offer much support to go with it.

But in FS.COM, you can get fully guarantees for their HP compatible SFPs. You get a true lifetime warranty, with parts replacement if needed, as well as unlimited technical assistance if you need any help. This greatly enhances the value of a product that's already a great value, and ensures your transceivers continue to function properly for the life of your network.

3. Prompt Shipment

Unlike many other vendors, FS.COM keeps a wide stock of our transceivers in-house and ready to ship. For hot products, we could deliver the same day while the market needs one week, and when the market needs two or three weeks, we only take one week, and the market one or two months, we half the month. In many cases, we can ship them to you same day.

Even if you're not looking to buy transceivers today, just keep that in mind. If there's ever an emergency, or a mistake when ordering new hardware, just contact us and we'll get you the transceivers you need as soon as possible.

But The Best Reason Is Huge Savings

Although the prices are very high for HP's own JD119B transceivers, they truly do not cost much to produce. They're priced according to the razor blade model, assuming that people with HP hardware are going to naturally buy HP SFPs as well. While FS.COM own HP compatible transceivers cost roughly one-tenth of the MSRP of HP's official transceivers. Even on sale from discount outlets, you'll still pay far more for the official version, but you won't actually get a better product, and you'll definitely get a worse warranty.

Whether you need HP compatible transceivers or any other brand-compatible transceivers, FS.COM can fulfill your requirements rapidly. As a vendor you can trust, FS.COM offers a wide range of transceivers suited for varied applications. Each of the optics is tested to ensure the 100% compatibility with major brands like Cisco, HP, Juniper, Nortel, Force10, D-link, 3Com, etc.

QSFP+ Interconnect Solution for 40 Gigabit Ethernet

The QSFP+ optical transceiver is the dominant transceiver form factor used for 40 Gigabit Ethernet applications. In the year of 2010, the IEEE standard 802.3ba released several 40-Gbps based solutions, including a 40GBASE-SR4 parallel optics solution for multimode fiber. Since then, several other 40G interfaces have been released, including 40GBASE-CSR4, which is similar to 40GBASE-SR4 but extends the distance capabilities.

As is know to all, two switches are connected by either transceiver modules or cables. For example, if you simply wanted to cable up two Nexus 3000s with 40GbE, the options are multi mode fiber or twinax copper. We’ll only cover the fiber throughout this post as that is where most of the questions are in recent years. So, since you are now using fiber, how do we connect these switches into the network? First, you need to insert the QSFP+ optic similar to how you would insert a fiber optic for standard 1G or 10G connectivity. For the Nexus 3000, only multi mode fiber is available, so the Cisco part number needed is QSFP-40G-CSR4. This is the equivalent of the GLC-LH-SMD or SFP-10G-SR, for 1G and 10G, respectively. The connector type for QSFP-40G-CSR4 is no longer LC, but is a MPO (multi-fiber push-on) connector.

It is worth noticing that cables for 40G Ethernet actually have 12 fiber strands internal to them to achieve 40GbE. Distance limitations are 100m using OM3 and 150m using OM4 fiber respectively. Because these cables are connected with MPO connectors, have 12 strands, and are ribbon cables for native 40GbE. They will not be able to leverage any of your existing fiber optic cable plant. So be prepared to home run these cable where needed throughout the data center.

However, you may not always need native 40GbE between two switches. Instead, you may opt to configure multiple 10GbE interfaces instead. In this case, the QSFP-40G-SR4 is still needed, but the cable selection is different with what was previously shown above and the ability to use current cable plants is possible. The cable required here would have an MPO connector on one end that would connect into the QSFP port and then “break out” into 4 individual fiber links on the other end. These breakout cables terminate with LC male connectors. I would like to call it MTP-LC harness cable. The application for this MTP-LC harness cable is to directly connect a QSFP+ port to (4) SFP+ ports. For most Data Center applications, the use of structured cabling is employed via MTP trunks and the use of patch panels.

This is great that they terminate with LC male connectors because this allows customers to leverage the current cable infrastructure assuming existing patch panels have LC interfaces and OM3/OM4 fiber is used throughout the data center. These breakout cables are also nice if you want to attach a northbound switch that only supports 10GbE interfaces. You can easily direct connect or jump through a panel in the data center to connect the Nexus 3000 via multiple 10GbE interfaces to a Nexus 7000 (or any other switch with 10GbE-only interfaces).

Accordingly, direct attach cables which are terminated with QSFP+ connector is an alternative in 40G connectivity. For instance, HP JG331A compatible QSFP+ to 4SFP+ direct attach copper cable is terminated with one QSFP+ connector on one end and four SFP+ connector on the other end.

40G QSFP+ cables can provide inexpensive and reliable 40G speed connections using either copper cables with distances reaching up to 30ft (10 meters length) or active optical cables reaching even 300ft (100 meters). Cost of local NOC connectivity is significantly reduced by avoiding the more costly fiber transceivers and optical cables.

How to Choose 10G Optical Transceivers

The IEEE 802.3ae committee ratified the 10 Gigabit Ethernet standard and along with the general specification, defined a number of fiber optic interfaces, such as 10GBASE-SR, 10GBASE-LR, 10GBASE-ER, 10GBASE-ZR, etc. These standard interfaces attempted to satisfy a number of different objectives including support for MMF and SMF compatibility. However, to select a matching transceiver for a given application and hardware is not that easy. The following stated parameters must be considered when choosing the 10G optical transceivers.

Transceiver “form-factor” / MSA Type

The transceiver has to mechanically and electrically fit into a given switch, router etc. Transceiver MSAs define mechanical form factors including electric interface as well as power consumption and cable connector types. XENPAK is the first MSA for 10 Gigabit Ethernet. The XENPAK MSA defines a fiber optic or wired transceiver module which conforms to the 10 Gigabit Ethernet standard of the IEEE 802.3 working group. Then X2 followed with smaller size. XFP specification was launched after X2 with more contact size. SFP and SFP+ are the newest and the most common form factors which enable 10G Ethernet.

Transport Media

Choose the right 10G optical transceivers according to the transport media, namely the fiber type. There are a number of 10 Gb/s media systems, with a few of the most widely used systems specified in the standard described here:

• 10GBASE-CX4 10 Gb/s Ethernet over short-range copper cable assemblies (15 m maximum).
• 10GBASE-T 10 Gb/s Ethernet over unshielded and shielded twisted-pair cables. Category 6A or better twisted-pair cables are required to reach the maximum distance specified.
• 10GBASE-SR 10 Gb/s Ethernet over short-range multimode fiber optic cables.
• 10GBASE-LR 10 Gb/s Ethernet over long-range single-mode fiber optic cables.

Connector Type

Choose the right transceivers which are compliant with the proper connectors. The connectors widely-used mainly have following types: Duplex LC connector, MPO connector, and MTP connector (a high performance MPO connector). For instance, HP 455883-B21 10GBASE-SR SFP+ transceiver module provided by Fiberstore is compliant with the Duplex LC connector.

Transmission Distance

When we choose the ideal 10G optical transceivers, we must consider the transmission distance and the reach requirements we need in reality. The most common types of transceivers divided by its transmission distance can reach up to 100m, 150m, 300m, 400m, 1km, 2km, 10km, 40km, etc. For example, Cisco Meraki MA-SFP-10GB-SR compatible 10GBASE-SR SFP+ transceiver supports link length of 300m over OM3 multi-mode fiber. While Cisco XFP10GLR-192SR-L compatible 10GBASE-LR XFP transceiver provides superior performance for SONET /SDH and Ethernet applications at up to 10km links.

Wavelength

The wavelength the transceivers operate with is an important factor in choosing the proper 10G optical transceivers. For instance, Fiberstore's 10G CWDM XFP is designed for single mode fiber and operates at a nominal wavelength of CWDM wavelength. There are fourteen center wavelengths available from 1350nm to 1610nm, with each step 20nm.

Fiberstore provides various types of 10G optical transceivers including single-mode and multi-mode with different channels and wavelengths. In order to achieve a fast and successful selection of the 10G optical transceivers, we should consider all the above-mentioned factors comprehensively.

Guide to High-Speed Copper Transceivers

The last few decades have seen the broad adoption of fiber optic transceivers used in optical communications for both telecommunication and data communications applications. However, would the copper connectivity withdraw from the market? Copper medium usually doesn’t require any transceivers, as they are part of the interface module. However, in order to cut down expenditures, some vendors use SFP copper transceiver with an RJ-45 female connector for Gigabit Ethernet connectivity over copper medium, or XFP copper transceiver for 10Gigabit Ethernet (10GbE) connectivity over CX4 copper. This article will give you a complete guide to these copper transceivers.

Supporting 10/100/1000 Mbps data-rate in excess of 100 meters (325 feet) reach over UTP Category5/5e cables, copper transceiver module is ideally suited for implementing small form-factor Network Interface Cards (NICs) and uplinks. As such, it is highly appropriate for use in high-density applications such as LAN 1000BASE-T, switch-to-switch interfaces, switched backplanes, blade servers, gaming devices, and router/server interfaces.

With the development of 1000BASE-T technology, 1000BASE-T and 100BASE-TX copper SFP transceiver over Category 5 copper cabling is an attractive option for network. The advantages are listed as follows:

• For 100m reach over Cat 5 UTP cable
• Hot-pluggable SFP footprint
• Supports RX_LOS as link indication function
• Fully metallic enclosure for low EMI
• Low power dissipation (1.05 W typical)
• Compact RJ-45 connector assembly
• Compliant with SFP MSA and IEEE Std 802.3-2002

Here are two good example of 1000BASE-T copper SFP transceivers, the Finisar FCLF-8521-3 compatible 1000BASE-T SFP copper transceiver and HP J8177C compatible 1000BASE-T SFP copper transceiver from FS.COM. Both of them are designed for 100m reach over Cat 5 UTP cable with RJ-45 interface and support max data rate of 1000Mbps.

As a kind of copper XFP transceiver, the XFP 10GBASE-CX4 module uses a CX4 connector to provide a connection to up to 15 meters over CX4 grade copper cable. Transparently to the user, the module transfers the 10GbE data stream over four full-duplex 3.125 Gbps channels over a single parallel copper cable. The product offers the ability to scale bandwidth in 10G increments, and directly with the industry standard MDI electrical socket.

CX4 is an extension of the four-channel 10 Gbps XAUI interface and is available in 70-pin MSA transponder modules, otherwise known as Xenpak, XPAK and X2. The 10GBASE-CX4 solution employs an Infiniband-style Twin-AX cable (click to see the Cisco 10G twinax). In this case, eight 100-ohm differential Twin-AX cables are bundled into a single outer shield. The center conductors are 24 AWG wire for compatibility with printed circuit board termination inside the connector housing. The limitation of the 10GBASE-CX4 solution is that it requires a 70-pin MSA socket and only supports the IEEE802.3ae 10GE data format.

The XFP format also offers the distinct feature of being data agnostic, which opens the market for the copper based solution to telecommunications applications as well. The 10 Gbps serial solution over copper adds the final link option to the XFP industry, offering everything from the ultra low-cost sub-20m 10 Gbps shelf-to-shelf and rack-to-rack links to 80 km or longer optical links.

Among the above-mentioned copper transceivers, what must be noticed is that copper SFP transceiver offers a flexible and simple method to be installed into SFP MSA compliant ports at any time with no interruption of the host equipment operation. It enables for seamless integration of fiber with copper LAN connections wherever SFP interface slots can be found. Such system is economical, it saves time, offers flexibility and eliminates the necessity for replacing entire devices once the customers have to change or upgrade fiber connections and you will benefit so much from it.