Abstract: A GaAs based semiconductor laser having a combination of cladding layers including a ridge structure part, and a remaining part which overlays the active layers of the laser, and an etch stop layer sandwiched between the ridge structure part and the remaining part. The remaining part preferably overlies the entire surface of laser active layers and has a thickness “D” which satisfies 1.1×W>D?0.5×W wherein W is the width of a spot size having a strength of 1/e2 as measured at the laser front facet in a direction perpendicular to the active layers, wherein “e” is the base of the natural logarithm. The semiconductor laser solves the kink phenomenon to obtain an excellent linear relationship between the optical output power and the injected current.

Abstract: A wavelength conversion module according to the present invention includes an external resonator, a semiconductor laser module and a wavelength conversion device for converting a wavelength of light output from the semiconductor laser module into a shorter wavelength. This wavelength conversion device includes at least one of a nonlinear crystal for generating SFG (Sum-frequency Generation) light and a nonlinear crystal for generating SHG (Second Harmonic Generation) light. Each of the SFG generating element and the SHG generating element of the wavelength conversion device may have a periodically-poled ridge-waveguide structure or a periodically-poled proton-exchanged-waveguide structure.

Abstract: A semiconductor laser module is provided for emitting pumping laser light which excels in temporal stability. The semiconductor laser module comprises a semiconductor laser device which has a layered structure formed on a GaAs substrate, wherein the layered structure has an active layer in a quantum well structure, formed of semiconductor materials including Ga and As, and a member having a light feedback function. The two components are optically coupled. A well layer in the active layer of the semiconductor laser device is a thick layer having a thickness of 10 nm or more. The active layer is doped with Si, and an n-type cladding layer underlying the active layer is also doped with Si.

Abstract: The semiconductor laser element comprises, from bottom to top, the p-AlxGa1?xAs upper clad layer, p-AlyGa1?yAs resistance control layer, and p-GaAs cap layer (where x>y>0.2). A portion of only the resistance control layer and cap layer is selectively etched. The etchant used for this etching is a mixture of organic acid and hydrogen peroxide based mixture, has such a composition such that the ratio of dissolution rate of the upper clad layer to the cap layer is between 10 and 20, and pH is between 7.4 and 7.6.

Abstract: A semiconductor laser device emitting a laser beam having stable emitting wavelength and a multimode spectrum is provided. The semiconductor laser device is a Fabry-Perot type semiconductor laser device having a layer structure including an active layer of a quantum well structure, and emitting a laser beam having wavelength stabilized by an action of return light and having a multimode spectrum, wherein each well layer satisfies relation: ?/d?1.3×10?3 nm?1 where ? and d(nm) are an optical confinement factor and a thickness of a well layer, respectively.

Abstract: The semiconductor laser device has the lower clad layer, active layer, upper clad layer, contact layer, the insulating film, and the positive electrode sequentially formed on the semiconductor substrate. The upper clad layer, the contact layer and the insulating film form the ridge. The positive electrode covers the upper and side faces of the ridge. The thickness of the positive electrode on the upper and side faces of the ridge is preferably substantially the same and it is not less than 150 nm.

Abstract: A semiconductor laser module is provided for emitting pumping laser light which excels in temporal stability. The semiconductor laser module comprises a semiconductor laser device which has a layered structure formed on a GaAs substrate, wherein the layered structure has an active layer in a quantum well structure, formed of semiconductor materials including Ga and As, and a member having a light feedback function. The two components are optically coupled. A well layer in the active layer of the semiconductor laser device is a thick layer having a thickness of 10 nm or more. The active layer is doped with Si, and an n-type cladding layer underlying the active layer is also doped with Si.

Abstract: A semiconductor laser device emitting a laser beam having stable emitting wavelength and a multimode spectrum is provided.

Abstract: A GaAs based semiconductor laser having a combination of cladding layers including a ridge structure part, and a remaining part which overlays the active layers of the laser, and an etch stop layer sandwiched between the ridge structure part and the remaining part. The remaining part preferably overlies the entire surface of laser active layers and has a thickness “D” which satisfies 1.1×W>D≧0.5×W wherein W is the width of a spot size having a strength of 1/e2 as measured at the laser front facet in a direction perpendicular to the active layers, wherein “e” is the base of the natural logarithm. The semiconductor laser solves the kink phenomenon to obtain an excellent linear relationship between the optical output power and the injected current.

Abstract: The semiconductor laser device has the lower clad layer, active layer, upper clad layer, contact layer, the insulating film, and the positive electrode sequentially formed on the semiconductor substrate. The upper clad layer, the contact layer and the insulating film form the ridge. The positive electrode covers the upper and side faces of the ridge. The thickness of the positive electrode on the upper and side faces of the ridge is preferably substantially the same and it is not less than 150 nm.

Abstract: A semiconductor laser diode has a GaAs substrate and a resonant cavity formed on the GaAs substrate. The resonant cavity includes a QW structure having a GaInAsN well layer and a AlGaAs or GaInAsP barrier layers. Specific combination of the indium content and the nitrogen content in the well layer alone or in combination with the specific composition of the barrier layers provides a long-term operation at a higher output power.

Abstract: A semiconductor laser module in which an exciting laser beam output is always allowed to be in a multi-mode and the variation of optical output does not occur. In the semiconductor laser module, a semiconductor laser device, light coupling means and an optical fiber are disposed, and further, a light feedback (return) portion where a laser beam of a specific wavelength is reflected is formed, and the reflection spectrum at the light feedback portion has a shape similar to a rectangular one.

Abstract: A exemplary method of fabricating a semiconductor laser device includes forming an electrode on each of a top surface and a bottom surface of a laminated structure comprised of semiconductor materials, then cleaving the laminated structure to form facets of a cavity, and next epitaxially growing a compound semiconductor on the facets of the cavity. Works involved in the cleavage and the epitaxial crystal growth are performed in a low oxygen and moisture concentration atmosphere, so that the occurrence of COD is suppressed in the fabricated semiconductor laser device.

Abstract: A semiconductor laser diode including: a resonator structure including a first facet having a reflection film and a second facet having an antireflection film; and an active region including a linear section a uniform width extending from the first facet along a direction of the resonator and a flared section extending from the linear section toward the second facet, the flared section having a tapered width increasing toward the second facet, wherein the relation of d<&lgr;0/{2·(2·n0·&Dgr;n)0.5} holds. The semiconductor laser diode which emits in a stabled fundamental mode can be realized by satisfying the above relation for increasing the effect for suppressing the spatial hole-burning phenomenon.

Abstract: A GaAs based semiconductor laser has a combination of cladding layers including a ridge structure part, and a remaining part which overlays the active layers of the laser, and an etch stop layer sandwiched between the ridge structure part and the remaining part. The remaining part preferably overlies the entire surface of laser active layers and has a thickness “D” which satisfies 1.1×W>D≧0.5×W wherein W is the width of a spot size having a strength of {fraction (1/e2)} as measured at the laser front facet in a direction perpendicular to the active layers, wherein “e” is the base of the natural logarithm. The semiconductor laser solves the kink phenomenon to obtain an excellent linear relationship between the optical output power and the injected current.

Abstract: The semiconductor laser element comprises, from bottom to top, the p-AlxGa1−xAs upper clad layer, p-AlyGa1−yAs resistance control layer, and p-GaAs cap layer (where x>y>0.2). A portion of only the resistance control layer and cap layer is selectively etched. The etchant used for this etching is a mixture of organic acid and hydrogen peroxide based mixture, has such a composition such that the ratio of dissolution rate of the upper clad layer to the cap layer is between 10 and 20, and pH is between 7.4 and 7.6.

Abstract: A GaAs based semiconductor laser has a combination of cladding layers including a ridge structure part and a remaining part sandwiching therebetween an etch stop layer. The remaining part overlies the entire surface of laser active layers and has a thickness “D” which satisfies D≧W×0.5 wherein W is the width of a spot size having a strength of 1/e2 for a near field pattern in the active layer in a direction perpendicular to the active layer, wherein “e” is the bottom of the natural logarithm.

Abstract: The semiconductor laser element comprises, from bottom to top, the p-AlxGa1-xAs upper clad layer, p-AlyGa1-yAs resistance control layer, and p-GaAs cap layer (where x>y>0.2). A portion of only the resistance control layer and cap layer is selectively etched. The etchant used for this etching is a mixture of organic acid and hydrogen peroxide based mixture, has such a composition such that the ratio of dissolution rate of the upper clad layer to the cap layer is between 10 and 20, and pH is between 7.4 and 7.6.

Abstract: A semiconductor laser diode has a GaAs substrate and a resonant cavity formed on the GaAs substrate. The resonant cavity includes a QW structure having a GaInAsN well layer and a AlGaAs or GaInAsP barrier layers. Specific combination of the indium content and the nitrogen content in the well layer alone or in combination with the specific composition of the barrier layers provides a long-term operation at a higher output power.

Abstract: The semiconductor laser device has a lower clad layer, an active layer, an upper clad layer, a forward mesa forming layer, a contact layer and an insulating film, sequentially formed on the semiconductor substrate. The upper clad layer, the forward mesa forming layer, the contact layer and the insulating film form a ridge. The etching speed of the forward mesa forming layer is higher than that of the upper clad layer and lower than that of the contact layer. Because of such etching speeds, the ridge having a forward mesa structure is formed.