Athermal Tuning for a Two-Section, All-Active DBR Laser With High-Order Grating

We incorporate thermal effects for injection currents ranging up to 150 mA in order to model the tuning behavior of a two-section, all-active distributed-Bragg-reflector (DBR), ridge-waveguide semiconductor laser utilized for a single-mode operation. In particular, we investigate wavelength tuning as a function of injected currents within the grating and phase/gain sections of the laser cavity and examine how any athermal lasing conditions may arise. The effect of thermal drift on the resonant wavelength due to a change in refractive index as well as thermal expansion of the laser cavity is included within a traveling wave analysis (TWA). From the TWA, the spatial distribution of gain along the active region of the laser is also derived in order to help describe the tuning behavior for a high-order (37th) grating previously optimized to minimize linewidth. A comparative analysis with a single mirrored, active-passive DBR laser is also included. Results show a good agreement with reported experimental data and compare well with the wavelength stability of other laser devices.