Broadening of gain spectrum using InGaAs/InAlGaAs multiple width quantum wells at 1550 nm

Summary form only given. We have investigated multiple width quantum well (MWQW) InGaAs/InAlGaAs material as a means of broadening the gain spectrum when compared with wafer structures with conventional identical width quantum wells (IWQW). MWQW semiconductor laser material consists of quantum wells of different widths in the same active region, emitting light at different wavelengths. We have measured broadening of gain spectra using MWQW material in comparison to IWQW material, which can be advantageous in producing colliding pulse mode-locked (CPM) lasers. In general, for mode-locked lasers, gain broadening should lead to shorter pulse width and we have observed more longitudinal modes in operation using MWQW than IWQW devices, implying shorter pulses at high repetition rates (>100 GHz).