CWDM Filters

A CWDM filter is a device which separates the signal of a single wavelength from many signals transmitted at different wavelengths. Optical signals are sent to the Common port, and separation takes place by transmitting a given wavelength to the Pass port and reflecting the rest of the spectrum to the Reflection fiber.

CWDM filters have higher channel isolation than solutions based on the FBT technology. They can be cascaded for new functionalities. Fibrain CWDM filters are characterized by a flat passband profile, low insertion losses and polarization losses. 

Example spectral profile of a CWDM filter:












  • High thermal stability of parameters
  • Low insertion and polarization losses
  • High channel isolation
  • Available with any type of fiber connectors
  • Delivered with test reports showing the whole spectral profile
  • ​Housing versions adapted to Customers' neeeds


  • CWDM systems
  • ADD/DROP solutions
  • Telecommunication networks
  • Optical amplifiers
  • CATV systems
Technical Data

1271-1611 nm band CWDM Add/Drop filters technical specifications 

Channel separation [nm]


Channel width [nm]

Λc +/- 6.5

Reflection bandwidth [nm]


Transmission bandwidth @-0.5 dB


Transmission band flatness [dB]

≤ 0.3

Transmission band attenuation [dB]

≤ 0.8

Reflection band attenuation [dB]

≤ 0.6

Adjacent channel isolation [dB]

≥ 30

Non-adjacent channel isolation [dB]

≥ 40

Reflection channel isolation [dB]

≥ 15

Directivity [dB]

> 55

Return loss  [dB]

> 50

PDL [dB]


Thermal band stability

0.003 nm/ 0C

Thermal attenuation stability

0.005 dB/ 0C

Input power [mW]

< 500 mW

Temperature operating range

from 0 to700C

Temperature storage range

from -40 to 850C

Notice: Parameters listed in the table refer to components without connector terminations

  • 250 μm output fibers: Ø34x5.5 mm
  • output fibers in 900 μm coating: Ø38x5.5 mm
  • output fibers in 0.9/2.0/3.0 mm coating: blackbox 90x20x10 mm