Monolithically-Integrated Dual-Wavelength Laser Diodes for Optical Pickups

Abstract

780 nm-band AlGaAs and 650 nm-band AlGaInP laser diodes are monolithically integrated on a GaAs substrate as the light source in DVD/CD optical pickups. In order to reduce internal losses for improved characteristics and to ensure better flexibility of device design, real-refractive index-guided self-aligned (RISA) structure is employed for both 780 nm and 650 nm-band LDs. As a result, low noise characteristics due to self-sustained pulsation in the both wavelength bands have been achieved. A dual-wavelength laser with a high power ( > 100 mW) 780 nm-band LD has also been developed for recording of CD-R/RW disks.