A Widely Tunable Three-Section DBR Lasers for Multi-Species Gas Detection

We demonstrate a widely tunable distributed Bragg reflector (DBR) laser operating at 1.8-µm, in which the DBR section was butt-jointed InGaAsP (λ = 1.45 μm) material. Through current and temperature tuning, a widely tuning range of over 11 nm with a side mode suppression ratio (SMSR) higher than 30 dB is obtained. Utilizing this DBR laser, the water and methane detection experiment has been successfully implemented, which illustrates the potential capacity of such DBR laser as the light source used for multispecies gas sensing. The work also illustrates that the butt-joint active-passive integration technology developed for the InGaAsP quantum-wells (QWs) can be successfully applied in the InGaAs QWs.