Monolithically integrated multi-wavelength MQW-DBR laser diodes fabricated by selective metalorganic vapor phase epitaxy

Abstract

Selective metalorganic vapor phase epitaxy (MOVPE) was used to grow InGaAsP/InP layers for fabricating multi-wavelength laser diodes. Multiple quantum well (MQW) active and passive waveguides were simultaneously grown by one step selective growth. The selectively grown layer thickness increases with the mask stripe width. This growth enhancement can be used to control the lasing wavelength of distributed Bragg reflector (DBR) laser diodes, because the effective refractive index of the MQW passive waveguide at the DBR region can be controlled by the mask stripe width. This simple technique was used to fabricate multi-wavelength MQW-DBR laser diodes. In the selective growth, the MQW structure was grown under 150 Torr to obtain large bandgap energy shift for the MQW passive waveguides compared to the active waveguide, which was effective for wide wavelength tuning range. On the contrary, a bulk InGaAsP guide layer was grown under 35 Torr to prevent too much composition shift and maintain high crystalline quality of the MQW passive waveguide. For 10 consecutive laser diodes, a wavelength span of over 20 nm with accurate wavelength control was achieved.