Available in Coarse Wavelength Division Multiplexing (CWDM) as well as 100 GHz and 200 GHz Dense WDM (DWDM) channel plans, these modular filters allow operators to multiplex up to 40 optical channels over a common fiber pair. Each filter offers a unique set of optical attributes, including one- to eight-channel wavelength multiplexing/demultiplexing counts; and support for SONET/SDH network or C/DWDM interworking via an add/drop function for a 1310 nm wavelength or an unspecified 1550 nm/DWDM passband.

The Common Optical Filters accommodate channel growth without service interruption. In addition, the filters’ low network-to-express loss allows stacking, which is essential for scaling new
wavelengths. Most filters are equipped with an express port to pass through non-dropped/added WDM channels. Interconnecting the express ports of two filters forms an Optical Add/Drop
Multiplexer (OADM) with east/west fiber connections, which is essential for ring and other 1+1 protected networks. High filter isolation eliminates disruptive “shadow” wavelengths and allows channels that have been dropped at a node to be used elsewhere downstream.

The CWDM channel plan comprises eight ITU G.694.2-compliant CWDM wavelengths. The CWDM filters are designed to accommodate extreme temperature conditions
ranging from -40°C to +85°C. This capability can reduce both deployment and operating costs significantly and offer added flexibility in network design, since the filters can be positioned directly along the fiber route with less concern for environmental stability.

The 100 GHz DWDM wavelength channel plan provides for maximum capacity, with 40 ITU G.694.1-compliant wavelengths divided into five groups of eight channels. This plan is interoperable with the 200 GHz DWDM plan to provide an upgrade path for operators with an installed 200 GHz system.

The 200 GHz DWDM wavelength channel plan, for mediumdemand routes, consists of 16 ITU G.694.1-compliant wavelengths. Intended for networks that do not require 40-channel support, the 200 GHz DWDM filters provide a reduced-cost alternative to the 100 GHz plan while maintaining the advantages of DWDM transport, such as longer reaches through amplification and higher channel counts than CWDM.

For operators who want to equip only a few initial wavelengths but maintain the ability to deploy additional channels at some future point in time without disrupting existing services, the Common Optical Filters are supported by band-splitter modules. These band-splitters facilitate upgrade paths by dividing the 200 GHz DWDM channel plan into two groups of eight wavelength channels, and the 100 GHz DWDM channel plan into five groups of eight wavelength channels. Once deployed, channel upgrades require only the insertion of the appropriate DWDM filter.

In addition, DWDM modules are equipped with both MUX and DeMUX optical taps to allow non-intrusive in-service monitoring of the DWDM signal.

Ciena also offers wide-band optical filters equipped with ports that add and drop a spectrum of wavelengths rather than a single wavelength. Depending on the application, these wide-band ports can be used to integrate additional wavelength services on the same fiber.

The 1310 filter port is intended to serve as an add/drop port for legacy SONET/SDH services, which typically use a 1310 nm signal. The 1310 ports allow WDM services to be deployed on fiber already carrying 1310 nm traffic.

The 1550/DWDM and 1550/CWDM ports are dual-function ports that can carry either a single unspecified 1550 nm signal or an aggregated DWDM or CWDM signal. The 1550/CWDM port covers all supported CWDM channels and typically connects to downstream CWDM filters that further MUX/DeMUX the individual CWDM channels. This port can be used to support unspecified 1550 or DWDM services in the same manner as the 1550/DWDM port, since both spectrums fall within the CWDM operating range.

All the Common Optical Filters contain a read-only storage EEPROM that retains pertinent information about the module. The native element management interfaces, such as CLI, and network management platforms access and use this information to create and maintain inventory databases.

Ciena may make changes from time to time to the products or specifications contained herein without notice.