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ntroduction to CCWDM Compact Coarse Wavelength Division Multiplexing

Time: 2019-02-28
        CCWDM, short for Compact Coarse Wavelength Division Multiplexing, is a wavelength division multiplexing technology based on Thin Film Filters (TFF). It operates on the same principle as CWDM modules, with the key difference lying in the cascading method of adjacent channels: CCWDM adopts free-space cascading via parallel light beams, whereas CWDM relies on fiber cascading. For CWDM, the filters of each channel are cascaded by optical fibers; in contrast, CCWDM has its collimators and filters soldered on a common substrate, with all channels cascaded through free space.
The left figure shows the fiber cascade and the right figure shows the free-space cascade
Figure 1: Left: Fiber Cascading; Right: Free-space Cascading
        As can be observed from Figure 1, the workflow of free-space cascading is as follows: optical signals carrying wavelengths of λ1, λ2…λn enter the free-space CCWDM device through the input optical fiber, and are then focused onto the first filter by the input lens. The optical signal with wavelength λ1 passes through the first filter and is coupled into the first output optical fiber via the first output lens, thus separating the λ1 signal. The remaining optical signals are reflected by the first filter to the next one for further separation. This process is repeated until all signals are separated. The coupling between wavelength channels is achieved through collimated light beams traveling in a zigzag path.
        Compared with CWDM modules, CCWDM packaged modules feature a significantly smaller form factor, along with lower insertion loss, and superior consistency. It can replace CWDM products in applications such as telecommunications networks, enterprise networks, PON networks and cable TV systems. Additionally, its low insertion loss minimizes signal attenuation during operation, further enhancing transmission reliability, thereby reducing the power requirements for signal transmitters.
        Moduletek's CCWDM modules boast mature manufacturing processes and stable, reliable performance. They support operation in ambient temperatures ranging from -40℃ to 85℃. Welcome to contact us for product inquiries and orders.
        If you have any questions about the above content, please contact us via email: sales@moduletek.com
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