Abstract

High-power AlGaInP diode lasers in the 600-nm wavelength band are being developed for many applications. To date, most commercial devices are double heterostructure lasers, usually narrow, index guided stripes intended for optical recording, laser printing, and holographic scanners, with λ ~ 670 nm, and power ~5–20 mW. For pumping chromium-doped solid-state laser materials, however, higher power diodes are required. This is particularly difficult, because the high thresholds and poor thermal conductivity of AlGaInP lasers make heating a serious problem for high-power operation. Using quantum well structures, however, substantial performance improvements have been achieved. For example, using a strained 70-Å single quantum well with graded-index optical confinement, powers exceeding 400 mW (cw) and 4 W (pulsed) at λ = 670 nm have been obtained. That is possible because of the diode’s low threshold current density of <400 A/cm². Thin GaInP quantum wells and quaternary AlGaInP active regions have also led to shorter wavelength lasers. For cw operation of thin MQW structures, for example, wavelengths of 630 nm are now possible. This overlaps the He-Ne laser and also lies closer to the peak of the broad 600-nm absorption of chromium in solid-state hosts.

© 1991 Optical Society of America