| 摘要 |
1,263,835. Semi-conductor diode lasers; heterojunction structures. STANDARD TELEPHONES & CABLES Ltd. 15 Oct., 1970, No. 49051/70. Headings H1C and H1K. A heterostructure GaAs-GaAlAs injection laser has a layer of GaAs 10 containing the PN junction sandwiched between two layers of GaAlAs the GaAlAs layers each forming an inner GaAlAs layer 11, 12 which is backed by an outer GaAlAs layer 13, 14 having a greater mole percentage of AlAs than the inner layers. The GaAlAs layers may be backed by further GaAs layers 16, 17 which have a lower electrical and thermal resistivity than the GaAlAs layers and one of which is in contact with a heat sink. One of the GaAs layers and one of the inner GaAlAs layers 11, 12 may be omitted, Figs. 2, 4 (not shown). The doping of the inner layers 11, 12 is made relatively low to decrease optical losses therein and in order to compensate for the increase in resistivity due to this low doping the outer layers 13, 14 are highly doped to decrease their resistivity.
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