Strain related degradation of highly tensile-strained multi-quantum well laser diodes

Incorporating strain in AlGaInAs multi-quantum well (MQW) active region is one of the key factors for achieving high performance laser diode for optical communication system. However, incorporating strain in thin film material may degrade the lattice or interface quality, which not only makes the crystal growth process challenging but also lead to gradual degradation behavior of optical device. In this work, four 1.3 um AlGaInAs laser diode epitaxial layers with different MQW strain compensation or growth parameter were fabricated by MOCVD. They were processed into ridge waveguide (RWG) laser diodes and burn-in test was carried out. By comparing the degradation behavior of the devices from the four wafers, it was concluded that strain compensation was the most important factor for achieving high reliability optical devices.