Sharp Kabushiki Kaisha Corporation

Ken Ohbayashi

Mitsuhiro Matsumoto

Masanori Watanabe

Kazuaki Sasaki

Kei Yamamoto

Hiroaki Ikeda

Takahiro Suyama

Osamu Yamamoto

Yoshie Fujishiro

Osumu Yamamoto

In a semiconductor laser device having an oscillation wavelength larger than 760 nm and smaller than 800 nm, at least a lower clad layer, a lower guide layer, an active region, an upper guide layer and an upper clad layer are supported by a GaAs substrate, the active region having a quantum well structure in which one or more well layers and barrier layers are stacked. The one or more well layers and the barrier layers are formed of any one of InGaP, InGaAsP and GaAsP, and the upper and/or lower guide layer is formed of AlGaAs (0.20&#x3c;z&#x2266;1).

Semiconductor laser device and optical disk unit using the same

A 780 nm band semiconductor laser device has an InGaAsP well layer, phosphorous composition of which is 0.51 smaller than 0.55 to prevent spinodal decomposition in growing InGaAsP. A compressive strain of 0.65% less than 1% and more than 0.25% is introduced into the well layer to reduce threshold current thereof. Thus, the 0.78-&#x3bc;m band semiconductor laser device having the InGaAsP well layer stably operates for a long time even in outputting a high optical power of 100 mW or more. A tensile strain of 1.2% is also introduced into barrier layers within the active region so as to compensate the stress due to the compressive strain of the well layer. As a result, the reliability of the semiconductor laser device is further increased during a high output operation.

Semiconductor laser device and optical disc drive

A semiconductor laser device according to the present invention includes: a semiconductor substrate having a first conductivity type; and a semiconductor multilayer structure provided on the semiconductor substrate, the semiconductor multilayer structure including an active layer. The semiconductor multilayer structure includes: a lower cladding layer provided below the active layer, the lower cladding layer having the first conductivity type; an upper cladding structure provided above the active layer, the upper cladding structure having a second conductivity type; and a cap layer provided above the upper cladding structure. A ridge is formed in the upper cladding structure, and a width of a lower face of the cap layer is larger than a width of an upper face of the ridge.

Semiconductor laser and a method for producing the same

A semiconductor laser device includes: a semiconductor substrate of a first conductivity type; a layered structure including at least a first cladding layer of the first conductivity type, an active layer, and a second cladding layer of a second conductivity type. The layered structure is provided on the semiconductor substrate. The semiconductor laser device also includes: a current blocking structure, having a striped concave portion therein, formed on the layered structure; and a third cladding layer of the second conductivity type provided so as to cover the striped concave portion and the current blocking structure. The current blocking structure includes at least a saturable absorbing layer having a forbidden band width which is substantially equal to a forbidden band width of the active layer.

Semiconductor laser device and method for producing the same

A semiconductor laser device according to the present invention includes: a semiconductor substrate having a first conductivity type; and a semiconductor multilayer structure provided on the semiconductor substrate, the semiconductor multilayer structure including an active layer. The semiconductor multilayer structure includes: a lower cladding layer provided below the active layer, the lower cladding layer having the first conductivity type, an upper cladding structure provided above the active layer, the upper cladding structure having a second conductivity type; and a cap layer provided above the upper cladding structure. A ridge is formed in the upper cladding structure, and a width of a lower face of the cap layer is larger than a width of an upper face of the ridge.

A semiconductor laser element includes: a semiconductor laminated structure for emitting a laser light, including an active layer interposed between a first cladding layer of a first-conductivity type and a second cladding layer of a second-conductivity type, the first cladding layer and the semiconductor layer having lower refractive indices than that of the active layer; and a current light confining means including a stripe-shaped semiconductor layer of the second-conductivity type formed on a surface of the second cladding layer on a side opposite to the active layer, for confining a laser driving current and the laser light in a region of the active layer corresponding to the stripe-shaped semiconductor layer, wherein the refractive index of the first cladding layer is larger than that of the second cladding layer in the semiconductor laminated structure, and the semiconductor laminated structure includes at least one semiconductor layer of the first-conductivity type having a lower refractive index than that of the first cladding layer, disposed between the first cladding layer and the active layer.

Semiconductor laser element and method for adjusting self-induced

A method for producing a semiconductor laser device includes the steps of: forming window layers on either one of a top surface of an internal structure or a reverse surface of a substrate and on light-emitting end facets of the internal structure; forming a reflection film on the light-emitting end facets; removing the window layer formed on either one of the top surface or the reverse surface by using an etchant which hardly etches the reflection film; and forming electrodes on the surface from which the window layer is removed by etching and on the other surface. Another method for producing a semiconductor laser device includes the steps of: forming window layers on light-emitting end facets of the bars; inserting the bars into an apparatus having openings for forming electrodes and a supporting portion for preventing a positional shift between the bars and the openings, and forming the electrodes on the top surfaces and the reverse surfaces of the bars; and cutting the bars into the chips.

Growing community of inventors

Nara-ken, Japan

Ken Ohbayashi