Abstract

A semiconductor laser device is capable of producing an increased optical output power with improved optical characteristics without being subjected to mode distortions in the output beam, while retaining advantageous features inherent to a semiconductor laser device of a buried heterostructure. The semiconductor laser device comprises an optical confinement region which is constituted by at least first, second, third and fourth semiconductor layers successively laminated on a predetemined semiconductor substrate. The second semiconductor layer has a relatively small refractive index and a relatively wide band gap as compared with those of the third semiconductor layer, while the first and the fourth semiconductor layers which are of the conductivity types opposite to each other have relatively small refractive indexes as compared with the second and the third semiconductor layers. The band gaps of the fourth and the second semiconductor layers are relatively large as compared with that of the third semiconductor layer. Difference in the band gap at least between the second and the third semiconductor layers is not smaller than 0.15 eV.

Other References

• Kressel et al., "Low-Threshold LOC GaAs Injection Lasers", Applied Physics Letters, vol. 18, No. 2, Jan. 15, 1971, pp. 43-45
• Tsukada, "GaAs-Ga_1-x Al_x As Buried-Heterostructure Injection Lasers", Journal of Applied Physics, vol. 45, No. 11, Nov. 1974, pp. 4899-4906
• Pawlik et Doppel-"Doppal-Hetero-Strukturkaser fur Optische Nachrichtenubertragung", Siemens Forsch.-u. Entwickl.-Ber. Bd. 2(1973), pp. 210-217
• Thompson et al., "(GaAl)As Lasers With a Heterostructure for Optical Confinement and Additional Heterojunctions for Extreme Carrier Confinement", IEEE Journal of Quantum Electronics, vol. QE-9, No. 2, Feb. 1973, pp. 311-318
• Casey et al., "GaAs-Al_x Ga_1-x As Heterostructure Laser with Separate Optical and Carrier Confinement", J. Appl. Phys., vol. 45, No. 1, Jan. 1974, pp. 322-333
• Cho et al., "Continuous Room-Temperature Operation of GaAs-Al_x Ga_1-x As Double-Heterostructure Lasers . . . ", App. Phys. Lett., vol. 28, No. 9, 1 May 1976, pp. 501-503
• Thompson et al., "Narrow-Beam Five-Layer (GaAl)As/GaAs Heterostructure Lasers . . . ", J. of Appl. Phys., vol. 47, No. 4, Apr. 1976, pp. 1501-1514
• Kajimura et al., "Leaky-Mode Buried-Heterostructure AlGaAs Injection Lasers", App. Phys. Lett., vol. 30, No. 11, June 1977, pp. 590-591