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Short wavelength and highly efficient AlGaInP quantum-well laser diode is promising as a red light source for small laser display application. Two kinds of the laser diodes are presented in this paper. A narrow ridge laser diode was designed for single lateral mode. In addition, a broad area laser diode was optimized for the higher power operation. To suppress a carrier leakage from an active layer, AlInP cladding layers were adopted to both of the lasers. Evaluation tests of the fabricated lasers were performed under CW operation. The wavelength of the narrow ridge laser was 636.0 nm under the condition of 25°C and 100 mW. Single lateral mode oscillation and the high wall plug efficiency of 29% were obtained. The beam divergences were 16° and 8° in fast and slow axes, respectively. The broad area laser showed lasing wavelength of 636.9 nm at 25°C for 200 mW output. The wall plug efficiency was 30% under this condition. Both of the lasers showed both high luminance and high wall plug efficiency. These lasers are suitable for small laser display applications.

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Area-selective disordering of an InGaAs strained quantum well was performed by rapid thermal annealing with thick and thin SiO2 caps. The lasing wavelength difference as large as 23 nm was obtained between Fabry-Perot lasers in 300 nm and 30 nm capped areas. We present fabrication of lasers integrated with disordered passive waveguides and demonstrate significant reduction of the passive waveguide loss from roughly 40 cm-1 to 3 cm-1.

In wavelength region of red color, luminous efficacy rapidly increases as wavelength shortens. In that sense, red laser diode (LD) with shorter wavelength is required for display applications. Experimental results for short wavelength limitation in AlGaInP LDs are shown and discussed in this paper. Broad area LDs with 625, 630, and 638 nm are successfully fabricated. Operation current versus output power (P-I) characteristics and its temperature dependence of 625 nm LD are inferior to that of 630 and 638 nm ones. The main reason might be carrier leakage, and the results indicate that additional countermeasures to carrier leakage should be adopted to realize a 625 nm LD with the same temperature characteristics as 630 and 638 nm LDs. Conversion efficiencies from input electrical power to luminous flux output of the LDs are also studied. 625 nm LD has low efficiency, though brightness of 625 nm light is 1.7 times of 638nm one with the same output power. And 630 nm LD shows better conversion efficiency at high luminous flux region than 638 nm one, though the P-I characteristics of 630 nm is worse than that of 638 nm one. The tendency is inverted at low flux region, indicating that the lasing wavelength of red LD for laser display should be chosen carefully.

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