CWDM Channel Plan
CWDM channel plan – full list of channels for CWDM systems, color coding and how we use them in pairs for bidirectional CWDM systems explained in this article.
CWDM (Coarse Wavelength Division Multiplexing) is one of xWDM technologies that allow to achieve greater data throughput and defined by per ITU-T G.694.2 specification consists but is not restricted to 18 CWDM Channels divided by wavelengths (λ) evenly spaced 20 nm apart between each channel from 1271 nm to 1611 nm as shown in Double Fiber CWDM Channel plan table:
|Nominal central wavelengths (nm)||Latch color by wavelength||BIDI Pair||Side|
To use CWDM based modules a requirement is to use a MUX/DEMUX unit at each end – additional information can be found at https://edgeoptic.com/product/bidi-cwdm/ and https://edgeoptic.com/passive-xwdm-wireless-fronthaul-basics/.
Number of channels for data transmission are dependent on MUX/DEMUX unit used as there are two main types Single Fiber (BiDi) CWDM MUX and Double Fiber CWDM MUX (Each CWDM MUX/DEMUX unit channel count and used wavelengths can be customized).
Single Fiber (BiDi) CWDM MUX
Provides ability to organize up to 9 parallel and independent data streams over single fiber of single-mode optical fiber and are organized in pairs. First module of pair is applied in one end of and second module of the same pair to other end. For example, SCMD-9A 1310 nm module will be transmit to SCMD-9B 1331 nm module and vice versa. Below You will find Single Fiber CWDM Channel plan table:
Double Fiber CWDM MUX
Doubles the bandwidth as it consists of 18 channels sending and receiving information over two SMF (Single-Mode Fiber) lines (one for sending, one for receiving). On both ends same CWDM channel module transmits data to other side and receives data from other side.