Wavelength monitoring of tunable DWDM sources using a FP etalon and a FP laser diode

We propose here a high-resolution tunable wavelength monitoring technique that combines the advantages of stable temperature properties of a Fabry Perot (FP) etalon filter as well as fast tunability of the transparent properties of a FP laser diode. Significant relief to the required temperature stability, about :0.2C, is achieved, so wavelength resolution of 0.01 nm can easily be obtained for many channels.