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.