Semiconductor laser device
AssigneeHitachi, Ltd.
InventorsToshiaki Tanaka, Takashi Kajimura, Toshihiro Kawano, Yuichi Ono
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Abstract
A high-power low-noise semiconductor laser device required for light sources for an erasable optical disc is a self-sustained pulsating semiconductor laser device in which an MQW structure is used for an active layer, and thus a kink output power and a light output power by which the self-pulsation is enabled are increased to 10 mW or more and noise is reduced. Another semiconductor laser device of a self-pulsation type has impurities that are doped in the active layer to reduce the self-pulsating frequency to obtain a low-noise characteristic even if higher optical feedback occurs. 259
Claims27
In a semi-conductor laser device of a double heterostructure, an active layer comprising one selected from the group consisting of a single quantum well structure, a structure including a single quantum well layer and, an optical guiding layer of a multi-quantum well structure formed on each side of the single quantum well layer, and a multi-quantum well structure, and the device performing a self-sustained pulsation.
A semiconductor laser device of a double heterostructure comprising an active layer formed on a semiconductor substrate, a first and a second cladding layer, the second cladding layer being disposed on the opposite side of the active layer from the semiconductor substrate and having a ridge stripe extending in the direction of extension of a laser cavity, a current-blocking and absorbing layer provided on the second cladding layer on each of both the sides of the ridge stripe, the effective transverse refractive index difference of the active layer being 8.times.10.sup.-4 -5.times.10.sup.-3, n- and p-type impurities being together doped in the active layer, and a pair of electrodes being electrically connected to the corresponding first and second cladding layers, whereby self-pulsation is performed.
Dependencies are inferred from the claim text.