Month: July 2016

Enhancing Network Capacity With CWDM Mux/Demux

In order to meet the never-ending demand for higher bandwidth and faster transmission rates, service providers and network managers are more inclined to seek help from fiber optics. However, as available fiber infrastructure is restricted and to add more fiber is no longer a feasible and economical option, it is hence vital to search for more cost-effective methods to enhance network capacity. Wavelength-divison multiplexing (WDM) is a technology which multiplexes multiple optical signals onto a single fiber by using different wavelengths or colors of light. This technology can greatly reduce the cost of increasing network capacity without having to move a single shovelful of dirt or hang a single new fiber.

CWDM Mux/Demux Overview

There are two types of WDM implementations: dense wavelength division multiplexing (DWDM) and coarse wavelength division multiplexing (CWDM). This article mainly offers CWDM Mux/Demux solutions for promoting network capacity.

CWDM Mux/Demux, short for coarse wavelength division multiplexing multiplexer/demultiplexer, has proved to be a flexible and economical solution which allows for expanding the existing fiber capacity effectively. The CWDM Mux/Demux enables operators to make full use of available fiber bandwidth in local loop and enterprise architectures. It can enhance capacity and increase bandwidth to the maximum over a single or dual fiber cable. Hence, by adopting CWDM Mux/Demux to the networking system, you are able to get other independent data links with less fiber cables required. CWDM Mux/Demux modules are wide from 2 channels to 18 channels in the form of 1RU 19’’ rack chassis.

CWDM Mux/Demux

The CWDM Mux/Demux has a long transmission distance coverage of multiple signals on a single fiber strand. It can support various types of signals such as 3Gbps/HD/SD, AES, DVB-ASI, Ethernet, etc. Furthermore, its ambient operating temperature is from -40℃ to 85℃, which means it is also suitable for outside plant applications. Besides, it requires no powering because of the thermally stable passive optics.

What Can CWDM Mux/Demux Achieve?

CWDM Mux/Demux functions to multiplex or demultiplex multiple wavelengths, which are used on a single fiber link. The difference lies in the wavelengths, which are used. In CWDM space, the 1310-band and the 1550-band are divided into smaller bands, each only 20nm wide. In the multiplex operation, the multiple wavelength bands are combined (muxed) onto a single fiber. In a demultiplex operation, the multiple wavelength bands are separated (demuxed) from a single fiber.

In a hybrid configuration (mux/demux), multiple transmit and receive signals can be combined onto a single fiber. Each signal is assigned a different wavelength. At each end, transmit signals are muxed, while receive signals are demuxed. For example, in a simple full-duplex link, the transmit is assigned the 1530nm wavelength, while the receive signal is assigned the 1550nm wavelength.

CWDM Mux/Demux Product Solution

A CWDM Mux/Demux with up to 18 channels has been introduced to cater for the ever-increasing demand for massive bandwidth and higher capacity. Just as the name indicates, a 18-channel CWDM Mux/Demux can combine up to 18 different wavelength signals from different optical fibers into a single optical fiber, or separates up to 18 different wavelength signals coming from a single optical fiber. FS.COM provides 18-CH CWDM Mux/Demux that is equipped with a monitor port, which is designed to ensure better CWDM network management.

This 18-CH CWDM Mux/Demux modules can multiplex and de-multiplex up to 18 CWDM sources over a single fiber with insertion loss below 4.9dB. It features a monitor port which ensures easy troubleshooting without downtime. Which efficiently contribute to expand the bandwidth of optical communication networks with lower loss and greater distance capacities.


In summary, CWDM Mux/Demux is a flexible and cost-effective solution that enables the expansion of existing fiber capacity and let operators make full of use of available fiber bandwidth in local loop and enterprise architectures. Fiberstore CWDM Mux/Demux is a universal device capable of multiplex multiple CWDM (1270~1610nm) up to 18 channels (2, 4, 5, 8, 9, 16, 18 channels are available) or optical signals into a fiber pair or single fiber. Together with our CWDM fiber SFP module or the wavelength converters, the bandwidth of the fiber can be utilized in a very cost-effective way.

User’s Guide To Third-Party Fiber Optic Transceivers Installation

Are you still hesitating to use third-party fiber optic transceivers? Maybe you haven’t noticed that the third-party ones are already predominant in the telecommunication market. Installing third-party fiber optic transceivers is relatively easy, providing you are using a transceiver that is MSA compliant and compatible with your brand of networking equipment. The following guide explains how to install third-party fiber optic transceivers:

1) Make sure you have the correct transceiver module for your device. Your device manual should contain a list of compatible transceiver models. The third-party transceiver module you purchase should also indicate which name brand manufacturer it is compatible with. For example, Fiberstore’s AFBR-79EEPZ QSFP+ transceiver is 100% compatible with Avago’s AFBR-79EEPZ. And their Cisco Linksys MGBT1 is 100% compatible with Cisco’s MGBT1.

2) Make sure you have the correct equipment and safety gear, such as a grounding device (e.g. ESD-preventative wrist strap), to prevent electrostatic discharge from damaging sensitive transceivers. If set down, fiber optic transceivers should be placed on a clean and static-free area, such as an antistatic mat.

3) Ensure that both the device’s transceiver ports and the transceiver’s plugs are clean and free of dust or oxidation. If the transceiver is new and won’t be used immediately, do not remove the dust plug. The dust plug at the end of a transceiver should only be removed at the time a fiber optic cable is inserted, and fiber optic cables should only be plugged into a transceiver after it is completely installed.

4) Properly orient the transceiver with the device slot. If your transceiver has a bail clasp (locking handle), pull it down until it clicks into a horizontal position. When installing a transceiver into a top slot, the bail clasp will typically be facing up when the transceiver is installed and locked into place. When installing transceivers into bottom slots, the bail clasp will typically be facing down when the transceiver is locked into place. Different devices can have different module socket configurations, so make sure you install the transceiver with the correct clasp-up or clasp-down orientation. For SFP and SFP+ transceivers, look for TX (transmit direction) and RX (receive direction) markings, or arrowheads, which will help you identify the proper orientation for the transceiver. Unnecessary removal and insertion should be avoided to prevent damaging both the transceiver and the device.


5) When you slide the transceiver into the device slot there should be an audible click to indicate that the transceiver is in place. Press the transceiver firmly in using your thumb. To ensure the transceiver is secure, lightly tug on it and try removing the module without releasing the bail clasp.


6) If installing more than one transceiver, repeat steps 1-5 until all transceivers are installed. After all transceiver modules have been inserted, it’s time to remove the dust plugs on any cable-ready modules and begin connecting fiber optic cables. It is recommended that you remove the dust plug on the fiber optic cables first, and inspect and clean the end-faces of the connecting cables. Then remove the dust plug on the transceiver just before the cable is plugged in. This will keep the sensitive components inside your third-party fiber optic transceiver module protected as long as possible.

Learning how to install fiber optic transceivers is very helpful even though you are not a professional telecom engineer. As long as you follow the six steps outlined above, you should be able to install most form-factors of third-party transceiver modules without any hitches. For XENPAK compatible transceivers, you will need a flathead screwdriver to tighten the installation screws in the transceiver’s faceplate into the faceplate of the connecting device.

Introduction to BiDi Optical Transceivers

In the past few decades, a new class of pluggable optical transceivers have been developed that send and receive optical signals end-to-end over a single fiber strand. This reduces by half the amount of fiber required for that same total data transmission. This factor-of-two improvement can lead to substantial cost savings especially in campus environments with large numbers of connectivity endpoints.

Bi-Directional transceivers, called BiDi’s for short, use two different wavelengths to achieve transmission in both directions on just one fiber. The modules are deployed in pairs, one for the upstream (“U”) direction and another for the downstream (“D”). The standard defining these parts is the IEEE 802.3ah Gigabit Ethernet 1000BASE-BXnn (nn= transmission reach in kilometers) specification for point-to-point Ethernet in the First Mile (EFM) applications.

BiDi transceivers

The value of the BiDi solution derives from the reduction in the use of fibers by a factor of two. There are many situations in real-world networks where this reduction is extremely important if not absolutely required. As mentioned above, the IEEE802.3ah specification defining BiDi’s mentions point-to-point Ethernet in the First Mile (EFM) applications. In addition, BiDi transceivers can be of great use in any situation where only limited fibers or limited conduit space is available. Other common applications include: digital video and Closed Circuit TeleVision (CCTV) applications and high-density switch-to-switch port interconnection.

BiDi Technology…how they work…

As mentioned above BiDi transceivers are deployed in matched pairs, one for the upstream (“U”) direction and another for the downstream (“D”), each part transmitting at a different wavelength. The figure below depicts the details of such a matched set of BiDi transceivers. In this example, the two wavelengths utilized by the BiDi pair are 1310nm and 1490nm. Typically the “Upstream” or “U” transceiver transmits at the shorter of the two wavelengths and the “Downstream” or “D” module the longer wavelength.

The key additional technology present in BiDi’s that is not present in standard 2-fiber transceivers is the “Diplexer”. The Diplexer acts simultaneously couples the locally transmitted wavelength onto the single fiber while “splitting” off the received wavelength so it is directed at the receiver.

Economic Case for BiDi’s

The value of the BiDi solution derives from the reduction in the use of fibers by a factor of two. There are many situations in real-world networks where this reduction is extremely important if not absolutely required. As mentioned above, the IEEE802.3ah specification defining BiDi’s mentions point-to-point Ethernet in the First Mile (EFM) applications. In addition, BiDi transceivers can be of great use in any situation where only limited fibers or limited conduit space is available. Other common applications include: digital video and Closed Circuit TeleVision (CCTV) applications and high-density switch-to-switch port interconnection.

The simplest economic case for BiDi’s is probably a campus environment requiring fiber connectivity to a large number of endpoints. For example, most universities campuses are spread over a fairly wide area and required high-speed (read: fiber) connectivity between campus core resources (e.g., databases, computing resources, common internet access, etc.) and a large number of classrooms, dorm rooms, and faculty and administrative offices. The following is a simple economic model to demonstrate the savings possible in such an environment using BiDi versus standard 2-fiber transceivers.

So, for a campus environment where average link length is greater than 800 feet, the BiDi solution is the right decision. In an real world example, a large university campus lighting 400 GbE fiber links with an average length of 1600 feet used BiDi’s to save $32,000 versus using 2-fiber transceivers.

FS.COM BiDi Offering

FS.COM offers BiDi transceivers in the SFP form-factor supporting 1GbE for all major switch brands like Cisco, HP, Juniper, Extreme, Brocade, etc. We offer a 1Gbps SFP BiDi’s to cover a wide range of distances including: 10km, 20km, 40km, 80km and 120km, all of which are ROHS compliant. To aid in turn-up and maintenance of BiDi links, all FS.COM BiDi transceivers support Digital Diagnostics Monitoring (DDM as defined in standard SFF-8472) allowing real-time monitoring of parameters of the fiber SFP, such as optical output power, optical input power, temperature, laser bias current, and transceiver supply voltage.

Selecting 10G SFP+ Optics Modules and Patch Cables

Nowadays, 10G connection in telecommunication network is gradually moving from the backbone to layer 2 and layer 3. Both technology and market of 10G optics modules are mature: the 10G optics modules have advanced from XENPAK which is the first generation of 10G transceiver to SFP+ which is now the most popular 10G optics. In addition, the price of 10G modules is getting lower. 10G modules are becoming affordable. Some genius guys even buy 10 SFP+ modules or SFP+ cable online to DIY private point to point 10G network. This article will offer basic information about 10G SFP+ optics modules and their connection instructions.

Basic of 10G SFP+ Optics

10G SFP+ transceiver has the same form factor of Gigabit SFP transceiver. Thus, many SFP+ modules can support 1/10G data rate to increase its flexibility during practical using. A SFP+ transceiver usually has two LC ports (as shown in the following picture). While 10G BiDi SFP+ transceiver, which transmitting and receiving signals from the same fiber optic cable, only has one LC port.


Apart from fiber optic transceivers, there are also various factory terminated copper-based or fiber optic based cables which are terminated with a SFP+ module on each end of the cable. There are mainly three types of these 10G cables: 10G SFP+ passive direct attached copper cable (like HP J9283B), 10G active direct attached copper cable and 10G SFP+ active optical cable. These 10G cables eliminate the used of additional patch cable and can be directly plugged into the SFP+ ports on switches. It is acceptable that these cables are an cost-effective and reliable solutions for 10G connections in short distance.

Optical Standards of 10G SFP+ Transceiver

According to IEEE standards, there are a variety 10GBASE SFP+ transceivers. For short distance transmission, 10GBASE-SR SFP+ and 10GBASE-LRM SFP+ can support transmission distance up to 300 meters and 220 meters over multimode fiber optic cables separately. 10GBASE-SR SFP+ modules is the most commonly used transceiver for short distance. It is suggested to work over wavelength of 850 nm.

There are a lot of 10G SFP+ transceivers that support long distance, like 10GBASE-LR SFP+, 10GBASE-ER SFP+, 10GBASE-ZR SFP+, CWDM SFP+, DWDM SFP+, BiDi SFP+, etc. These transceivers can support transmission distances ranging from 10 km to 120 km over single-mode fiber optic cables.

There is another special type of 10G SFP+ transceivers which has been mentioned in this post, which is known as dual-rate SFP+. For example, dual-rate 1000BASE-LX and 10GBASE-LR SFP+ transceiver can be adjusted to support both 1G and 10G data rate up to 10 km over wavelength of 1310 nm.


Fiber Patch Cable Selection Guide for 10G Transceivers

As 10G SFP+ DAC and AOC eliminate the using of additional patch cords. This part will introduce the selection guide for 10G SFP+ transceivers. During the selection of fiber optic patch cables for 10G transceivers, the transmission distance is the first element to be considered. Single-mode patch cable is used for long distance transmission and multimode is designed for short distance transmission. Then the ports on the transceiver for receiving and transmitting should be considered. As mentioned, most 10G SFP+ transceiver use duplex LC port, while BiDi SFP+ use simplex port. Thus, simplex LC patch cords or duplex LC patch cords are used according to the port type on the transceiver.


Although newer standards for higher speed, like 40Gbps and 100Gbps have already been launched, it can still be predicted that, 10G connections especially the SFP+ based optics and cables are bound to continue to dominate the market for the next 10 years or more.