Optical characterization of an asymmetric quantum well structure for broadband laser array application

Distributed feedback (DFB) lasers based on AlGaInAs asymmetric quantum wells (AQWs) have been designed and fabricated. The active region comprises of three 6.4nm and six 5nm wells, with +1.3448% compressive strain in quantum wells and 0:7379% tensile strain in barriers. Material quality was characterized by photoluminescence (PL) and photorefletance (PR) investigation. Broadband characteristic was confirmed by a 98 nm wide room temperature PL spectrum centering at 1520 nm. The details of transition energies and their associated quantized energy levels in both types of wells were studied by PR measurement and the results were compared with numerical simulation results and PL spectra. DFB lasers worked in the wavelength range from 1502.8 to 1535.2 nm. Although channels at longer wavelength failed due to process defect in grating, numerical simulation and laser performance analyses indicated that the modal gain of the channel at 1532.2nm was supported by wide wells.