Precompensation Techniques to Suppress the Thermally Induced Wavelength Drift in Tunable DBR Lasers

Wavelength drift caused by thermal transients is a major problem in optical routers which use semiconductor tunable lasers for packet switching. Wavelength drift is induced by the temperature variations in laser sections caused by switching of the tuning currents. A thermal model is used to analyze the optical frequency drifts due to the thermal characteristics of the laser chip and its mount. We investigate the impact of thermal effects on switching behavior of a three-section distributed Bragg reflector laser and show numerically that the wavelength drift can be counteracted by using precompensation of passive section currents. Results from numerical simulation show that the wavelength drifts can be suppressed by more than 80%.