Tadashi Takeoka

High-Power 780 nm AlGaAs Narrow-Stripe Window Structure Lasers with Window Grown on Facets

A novel window structure referred to as window grown on facets (WGF) is applied to a 10%-95% coated narrow-stripe laser with a wavelength of 780 nm. An aspect ratio of 2 in the beam divergence without a decrease in the differential quantum efficiency is obtained by optimizing the narrow-stripe structure. Highly reliable operation under 70 mW CW at 60°C is attained beyond 4000 hours.

Reliable red-emitting laser diodes grown by solid source molecular beam epitaxy

Abstract We achieved over 1000 h stable continuous wave (CW) operation of AlGaInP laser diodes (LDs) with output power of 30 mW at 50°C by using all solid source molecular beam epitaxy (MBE). In this paper the essential points for reliability are described. If sufficient outgassing of source materials was performed, secondary ion mass spectrometry (SIMS) signals of hydrogen and oxygen from the as-grown layers became small. Reduction of these impurities dramatically increased photoluminescence (PL) intensity and decreased the threshold currents of LDs. Growth condition dependence of device performance was also investigated. Whilst the acceptable ranges of V/III ratio and phosphorus cracking temperature needed to obtain reliable operation were extensive, the suitable growth temperature range was limited.

Dependence of window effects on Al content of a window layer in high‐power AlGaAs window structure lasers with window grown on facets

In high‐power AlGaAs window structure lasers with a window grown on facets (WGF) structure, dependence of window effects on Al content of the window layer is examined. When the Al content of the window layer is more than that of the cladding layer, the window effects are found. But, in other cases, the window effects do not occur. A calculation of a carrier leakage from the active layer to the window layer is performed. From the result, we deduce that the reduction of the window effects is caused by the carrier leakage. In the WGF laser with the confirmed window effects, a maximum output power of 350 mW is achieved and highly reliable operation under 100 mW at 50 °C beyond 10000 h is attained.