As you know, wavelength-division multiplexing (WDM) is a technology which multiplexes a number of optical carrier signals onto a single optical fiber by using different wavelengths of laser light, this technology is widely used in fiber optic communications. This technique no only enables bidirectional communications over one strand of fiber, but also multiplication of capacity.
WDM systems are divided into different wavelength patterns, conventional/coarse (CWDM) and dense (DWDM). CWDM systems provide up to 8 channels in the 3rd transmission window (C-Band) of silica fibers around 1550nm. DWDM uses the same transmission window but with denser channel spacing. Channel plans vary, but a typical system would use 40 channels at 100 GHz spacing or 80 channels with 50 GHz spacing. Some technologies are capable of 12.5 GHz spacing (sometimes called ultra DWDM). Such spacings are today only achieved by free-space optics technology. New amplification options (Raman amplification) enable the extension of the usable wavelengths to the L-band, more or less doubling these numbers.
There are two basic types of WDM solutions – both are available for CWDM and DWDM implementations depending on customer requirements:
Transponder-Based Solutions: Allows connectivity to switches with standard 850 or 1310nm optical SFP transceivers. A WDM transponders are used to convert these signals using Optical-to-Electrical-to-Optical (O-E-O) conversion to WDM frequencies for transport across a single fiber. By converting each input to a different frequency, multiple signals can be carried over the same fiber.
SFP-Based Solutions: These eliminate the need for transponders by requiring switch equipment to utilize special WDM transceivers (also known as colored optic), reducing the overall cost. Coarse or Dense WDM SFPs are like any standard transceiver used in Fibre Channel switches, except that they transmit on a particular frequency within a WDM band. Each wavelength is then placed onto a single fiber through the use of a passive multiplexer. The WDM transceivers utilize a single strand of fiber to transmit network traffic on separate receive and transmit wavelengths (1310/1550 nm). This innovative technology allows you to effectively use the two strands for two independent connections or to double the capacity without running a second fiber cable.
The Trends Of Larger Demand Of WDM Transceivers
Optical transceiver modules are key components for WDM equipment for large capacity/long distance transmission across optical fiber. The market for WDM modules is expected to reach more than $770 million in revenues as carriers make the shift to a WDM-based transport infrastructure in order to support new high bandwidth services and their promised 100 Gbps backbones.
ROADM deployment is also creating larger addressable markets for WDM modules. After years of merely being talked about, these WDM boxes are now being deployed much more widely and finally allowing operators to capitalize on their ability to provide greater flexibility of network design, integration of SDH and OTN, fast service activation and high bandwidth efficiency.
The newly developed optical WDM transceiver module has the advanges of low cost, high performance, and compact size. Choosing Cisco CWDM 10G or 10g dwdm at FiberStore.com.
