Long-term wavelength stability of 1.55-μm tunable distributed Bragg reflector lasers

To investigate physical mechanisms involved in long-term wavelength drift of tunable distributed Bragg reflector (DBR) laser, the evolution of the tuning characteristics as well as the Bragg section intensity modulation response of several DBR lasers have been simultaneously assessed by current injection in the Bragg section only. Current versus voltage I(V) characteristics under aging have also been recorded to compare the role of leakage current and nonradiative recombination defect evolution. The wavelength drift as well as the carrier lifetime of the tuning section varies following an exponential law A+Bexp(-t_A/τ) versus aging time t_A. The time constant τ is aging temperature and Bragg current dependant. The carrier lifetime decreases with time indicating a wavelength drift mainly due to nonradiative recombination defect increase. Modeling of the I_B(V) and λ_B(I_B) characteristics is presented, that fits nicely the experimental data. The exponential form of the wavelength drift is used to propose novel and adequate burning conditions of DBR lasers