Product overview

The WLTF-FL-O series is a wavelength tunable filter with a built-in attenuator and power monitor. It allows continuous tuning from 1260 to 1340 nm, covering the most important wavelength region in the O-band. The flat-top transmission spectrum with high out-of-band suppression enables selectively characterize one wavelength from the 100GBASE-LR4, 400GBASE-LR8, and 100GBASE-CWDM4 wavelengths. Combined with FiberLabs’ O-band fiber amplifiers, the WLTF-FL-O is an ideal solution for transceiver testing.

Front view of WLTF-FL-O


  • Continuously tunable over the entire 100GBASE-LR4, 400GBASE-LR8, 100GBASE-CWDM4 wavelengths
  • Wide range of bandwidth selection (fixed bandwidth, specified by customer when placing order)
  • Flat-top transmission spectrum
  • High out-of-band suppression (> 40 dB)
  • Built-in attenuator and power monitor
  • External control (GP-IB and RS-232C)


  • Transceiver testing

Application of WLTF-FL-O for 100GBASE-LR4 transmitter testing

Transmission spectra examples

WLTF-FL-O-80-2.5 (FWHM: 2.5 nm)

Example 1: Tuned to 100GBASE-LR4 wavelengths Example 2: Tuned to 400GBASE-LR8 wavelengths

WLTF-FL-O-80-6.0 (FWHM: 6.0 nm)

Example 1: Tuned to 100GBASE-CWDM4 wavelengths