Wavelength Locking a Fast-Switching Tunable Laser

We demonstrate wavelength locking in a widely-tunable fast-switching laser module that accesses 64 ITU channels with 50 GHz spacing and switches wavelength in under 50 ns. We use a Fabry-Perot etalon to produce the error signal that is used to stabilize the laser frequency against long-term drifts. We demonstrate locking while continuously switching with random channel shcedules of 1 mus packets. The locked frequency accuracy of +-3 GHz is a factor of 2 improvement over operation without locking. We also present the dynamics of the frequency drift due to temperature variation in the laser, and show the correlation between the frequency offsets while locking and the electrical power dissipated in the tuning sections.