High reliability of high-power and widely tunable 1.55-μm distributed Bragg reflector lasers for WDM applications

Single-mode operation with output power up to 100 mW is reported for the first time for InGaAsP-InP DBR lasers. These devices exhibiting a record 17-nm tuning range, have been realized using a three-step MOVPE process. The output power variations under tuning are limited to about 1.5 dB, and the tuning range remains quasiconstant with the output power. Using a two-wavelength DBR laser array with Bragg wavelengths spaced by 15 nm, 61 channels regularly spaced by 0.5 nm are accessible by controlling only two currents. Moreover systematic investigations of accelerated aging of these components have been realized for the first time. For all the tests performed on both active and tuning sections, no spectral degradations are observed, and the tunability remains unchanged. To define the lifetime of a tunable laser, e.g., a DBR laser, we propose a new failure criterion based on both active operating current and wavelength degradations. Using this criterion, the lifetime at 60°C is estimated to be more than 7·10⁴ h, and is not limited by the wavelength degradation, but effectively by the operating current degradation