How to Selecte CWDM SFP Transceivers

by www.fiber-mart.com

As an extension of wavelength division multiplexing (WDM), coarse wavelength division multiplexing (CWDM) is a technology that multiplexes a number of optical carrier signals onto a single optical fiber through the use of different wavelengths (i.e., colors) of laser light. A CWDM SFP (Small Form-factor Pluggable) transceiver is a hot-swappable input/output device that plugs into an SFP port or slot of a switch or router, linking the port with the fiber-optic network. It is a  kind of optical-electric/electric-optical converter. With the transmitter on one end, the CWDM SFP transceiver takes in and converts the electrical signal into light, after the optical fiber transmission in the fiber cable plant, the receiver end again converts the light signal into electrical signal. The following figure shows the CWDM SFP transceiver in the CWDM system. In the figure, TX represents “transmit”, RX represents “receive”. Being a kind of compact optical transceiver, CWDM SFP transceiver is widely used in optical communications for both telecommunication and data communication. It is designed for operations in Metro Access Rings and Point-to-Point networks using Synchronous Optical Network (SONET), SDH (Synchronous Digital Hierarchy), Gigabit Ethernet and Fibre Channel networking equipment.

 

Three Components of CWDM SFP Transceivers

The CWDM SFP transceiver consists of an un-cooled CWDM Distributed Feed Back (DFB) laser transmitter, a PIN photodiode integrated with a Trans-impedance Preamplifier (TIA) and a Microprogrammed Control Unit (MCU). The DFB laser used in the CWDM SFP transceiver transmitter is a 18 CWDM DFB wavelengths laser. It is well suited for high capacity reverse traffic. Obeying the standard diode equation for low frequency signals, The PIN photodiode has a 80km transmission distance. And the MCU is a high-speed, executive, input-output (I/O) processor and interrupt handler for the NRL Signal Processing Element (SPE).

 

Advantages of CWDM SFP transceivers

Using existing fiber connections efficiently through the adoption of active wavelength multiplexing, CWDM SFP transceivers have improved the designs of telecommunications devices and other technologies. Here are some advantages of CWDM SFP transceivers:

 

Scalability and Flexibility—CWDM SFP transceivers can support multiple channels. It means that more channels can be activated as demand increases. CWDM SFP transceivers have a wide variety of network configurations that range from the meshed-ring configurations to the multi-channel point-to-point. In point-to-point configurations, the two endpoints will connect directly through a fiber link, allowing users to add or delete as many as eight channels at a time.

 

Low Risks in Investment—Most CDWM SFP transceivers have a low failure rate, which is less likely to be the reason why the user’s solution fails. It helps enterprises increase the bandwidth of the Gigabit Ethernet optical infrastructure without adding any additional fiber strands and can also be used in conjunction with other SFP devices on the same platform. Thus the user will be able to re-invest the capital saved by avoiding prematurely failed devices.

 

Selecting a Right CWDM SFP Transceiver

There are many kinds of CWDM SFP transceivers in the market. Their wavelengths are available from 1270 nm to 1610 nm, with each step 20 nm. Different CDWM SFP transceivers have different color codes, distances, date rates and laser operating wavelengths. For example, the CWDM-SFP-1470, which is colored gray, is one of Cisco CWDM SFP. It is a CWDM SFP transceiver that rates for distances up to 80 km and a maximum bandwidth of 1Gbps, operating at 1470nm wavelength. Customers may choose a CWDM SFP transceiver in accordance with their actual needs.

 

Applied to the access layer of Metropolitan Area Network (MAN), CWDM is a low-cost WDM transmission technology. fiber-mart.com provides the aforesaid CWDM-SFP-1470 and other types of CWDM SFP transceivers, which are convenient and cost-effective solution for the adoption of Gigabit Ethernet and Fibre Channel in campus, data center, and metropolitan-area access networks.

Full CWDM Mux Demux and CWDM SFP Transceivers Solutions

by www.fiber-mart.com

CWDM systems have channels at wavelengths spaced 20 nanometers (nm) apart, compared with 0.4 nm spacing for DWDM. This allows the use of low-cost, uncooled lasers for CWDM. In a typical CWDM system, laser emissions occur on full eighteen channels at eighteen defined wavelengths: 1610 nm, 1590 nm, 1570 nm, 1550 nm, 1530 nm, 1510 nm, 1490 nm, 1470 nm, 1450 nm, 1430 nm, 1410 nm, 1390 nm, 1370 nm, 1350 nm, 1330 nm, 1310 nm, 1290 nm, 1270 nm. Besides, for CWDM systems an industry standard color coding scheme is used. The latches of the CWDM SFP transceivers match the colored port indicators on the passive units therefore guaranteeing simple setup. Following color codes and wavelength are valid for CWDM.

 

Full CWDM Channels (18 Channels) Mux Demux Solution

The WDM system uses a multiplexer at the transmitter to combine several wavelengths together, each one carry different signal with bite-rate up to 10G and a demultiplexer at the receiver to split them apart. Both mux and demux are passive, requiring no power supply. The 18 Channels CWDM mux demux covers all channels of 1270nm to 1610nm in 20nm increments. Without replacing any infrastructure, it totally support data rates up to 180 Gbps by being completely protocol transparent. The main fields of applications are the use in SDH (STM-1, STM-4, STM-16, STM- 64), IP (Fast Ethernet, Gigabit Ethernet, 10 Gigabit) ATM and storage (1G, 2G, 4G, 8G, 10G Fibre Channel) networks. Connectors, located on the front of the CWDM mux demux modules, are labeled and use the same color-coding that is used to indicate the wavelength of the individual CWDM SFP transceivers (shown in the figure below).

 

When fiber availability is limited, CWDM mux demux could increase the bandwidth on the existing fiber infrastructure. By using 18ch CWDM mux demux mentioned above and the CWDM SFP transceivers, up to 180 Gbps could be supported on a fiber pair.

 

Full CWDM SFP Transceivers Solution

CWDM SFP transceiver is based on the SFP form factor which is a MSA standard build. The max speed of this product is 1.25G and they are also available as 2.5G and of course the popular CWDM 10G SFP transceivers. The CWDM SFP transceiver has a specific laser which emits a “color” defined in the CWDM ITU grid. The CWDM ITU grid is defined from 1270 to 1610nm and has steps of 20nm. So the available wavelength is 1270nm, 1290nm, 1310nm, 1330nm, 1350nm, 1370nm, 1390nm, 1410nm, 1430nm, 1450nm, 1470nm, 1490nm, 1510nm, 1530nm, 1550nm, 1570nm, 1590nm and C. Besides, our CWDM SFP transceivers are similarly color-coded as the CWDM mux demux to help you match the right link connection (shown in the figure below).

 

We can make the CWDM SFP transceivers compatible with every brand (Cisco, HP, H3C, Juniper, Huawei, Brocade, Arista). A lot of brands have vendor locking and only with the proper coding. fiber-mart is specialized in this rebranding or recoding. We have many different switches and routers in our test lab to test the coding. We also use different Optical Spectrum Analyzers to ensure the CWDM SFP transceiver is emitting the right color and has the correct power budget. The CWDM SFP transceiver is used in combination with passive CWDM mux demux, and we can provide you a complete solution and advice on which equipment fits best in your project. Please give us your project details and we will provide the most efficient and economical solution.