A temperature-tunable Fabry-Perot filter made of silicon has been developed and applied for simultaneous spectral filtering and wavelength monitoring of a directly modulated DFB laser. This novel device decreases the dispersion penalty of a cost-effective dense wavelength-division-multiplexing (DWDM) transmitter in a long-haul transmission link. Moreover, it allows the operating wavelength of the transmitter to be accurately monitored in real time.
Niemi, T., Uusimaa, M., Tammela, S., Heimala, P., Kajava, T., Kaivola, M., & Ludvigsen, H. (2001). Tunable silicon etalon for simultaneous spectral filtering and wavelength monitoring of a DWDM transmitter. IEEE Photonics Technology Letters, 13(1), 58-60. https://doi.org/10.1109/68.903220