A semiconductor laser comprising a single mode laser cavity having a stack of semiconducting layers defining a transversal p-n junction is provided. A plurality of electrodes are coupled to corresponding sections of the laser cavity along the longitudinal light propagation direction, each corresponding section defining one of an amplification section or a modulation section. One or more DC sources are coupled to the electrodes associated with the amplification sections to forward-bias the p-n junction above transparency, so as to provide gain in the associated amplification sections. One or more modulation signal sources are coupled to the electrodes associated with the modulation sections, and apply a modulation signal across the p-n junction below transparency, the modulation signal providing a modulation of an output optical frequency of the semiconductor laser. Each modulation section is operated in photovoltaic mode.

An optical device has a gallium and nitrogen containing substrate including a surface region and a strain control region, the strain control region being configured to maintain a quantum well region within a predetermined strain state. The device also has a plurality of quantum well regions overlying the strain control region.

A semiconductor laser device includes a first cladding including gallium nitride (GaN) on a substrate, a light waveguide on the first cladding, a first contact pattern, a first SCH pattern, a first active pattern, a second SCH pattern, a second cladding and a second contact pattern sequentially stacked on the light waveguide, and first and second electrodes on the first and second contact patterns, respectively.

A semiconductor device includes a substrate comprising a layer made of Ge and a semiconductor multilayer structure grown on the layer made of Ge. The semiconductor multilayer structure includes at least one first layer comprising a material selected from a group consisting of Al.sub.xGa.sub.1-xAs, Al.sub.xGa.sub.1-x-yIn.sub.yAs, Al.sub.xGa.sub.1-x-yIn.sub.yAs.sub.1-zP.sub.z, Al.sub.xGa.sub.1-x-yIn.sub.yAs.sub.1-zN.sub.z, and Al.sub.xGa.sub.1-x-yIn.sub.yAs.sub.1-z-cN.sub.zP.sub.c, Al.sub.xGa.sub.1-x-yIn.sub.yAs.sub.1-z-cN.sub.zSb.sub.c, and Al.sub.xGa.sub.1-x-yIn.sub.yAs.sub.1-z-cP.sub.zSb.sub.c, wherein for any material a sum of the contents of all group-III elements equals 1 and a sum of the contents of all group-V elements equals 1. The semiconductor multilayer structure also includes at least one second layer comprising a material selected from a group consisting of GaInAsNSb, GaInAsN, AlGaInAsNSb, AlGaInAsN, GaAs, GaInAs, GaInAsSb, GaInNSb, GaInP, GaInPNSb, GaInPSb, GaInPN, AlInP, AlInPNSb, AlInPN, AlInPSb, AlGaInP, AlGaInPNSb, AlGaInPN, AlGaInPSb, GaInAsP, GaInAsPNSb, GaInAsPN, GaInAsPSb, GaAsP, GaAsPNSb, GaAsPN, GaAsPSb, AlGaInAs and AlGaAs.

An AlGaInPAs-based semiconductor laser device includes a substrate, an n-type clad layer, an n-type guide layer, an active layer, a p-type guide layer composed of AlGaInP containing Mg as a dopant, a p-type clad layer composed of AlInP containing Mg as a dopant, and a p-type cap layer composed of GaAs. Further, the semiconductor laser device has, between the p-type guide layer and the p-type clad layer, a Mg-atomic concentration peak which suppresses inflow of electrons, moving from the n-type clad layer to the active layer, into the p-type guide layer or the p-type clad layer.

A gallium and nitrogen containing laser diode device. The device has a gallium and nitrogen containing substrate material comprising a surface region. The surface region is configured on either a non-polar crystal orientation or a semi-polar crystal orientation. The device has a recessed region formed within a second region of the substrate material, the second region being between a first region and a third region. The recessed region is configured to block a plurality of defects from migrating from the first region to the third region. The device has an epitaxially formed gallium and nitrogen containing region formed overlying the third region. The epitaxially formed gallium and nitrogen containing region is substantially free from defects migrating from the first region and an active region formed overlying the third region.

A plurality of dies includes a gallium and nitrogen containing substrate having a surface region and an epitaxial material formed overlying the surface region. The epitaxial material includes an n-type cladding region, an active region having at least one active layer overlying the n-type cladding region, and a p-type cladding region overlying the active region. The epitaxial material is patterned to form the plurality of dies on the surface region, the dies corresponding to a laser device. Each of the plurality of dies includes a release region composed of a material with a smaller bandgap than an adjacent epitaxial material. A lateral width of the release region is narrower than a lateral width of immediately adjacent layers above and below the release region to form undercut regions bounding each side of the release region. Each die also includes a passivation region extending along sidewalls of the active region.

Gallium and nitrogen containing optical devices operable as laser diodes and methods of forming the same are disclosed. The devices include a gallium and nitrogen containing substrate member, which may be semipolar or non-polar. The devices include a chip formed from the gallium and nitrogen substrate member. The chip has a width and a length, a dimension of less than 150 microns characterizing the width of the chip. The devices have a cavity oriented substantially parallel to the length of the chip.

The grating layer of a surface emitting laser is divided into a first grating region and a second grating region along a horizontal direction. The second grating region is located at a middle area of the grating layer, while the first grating region is located in an outer peripheral area of the grating layer. Each of the first and second grating regions comprises a plurality of micro-grating structures. The grating period of the micro-grating structures in the first grating region is in accordance with the following mathematical formula: $.Math.=m\frac{\lambda }{2*n_{\mathrm{eff}}};$
in addition, the grating period of the micro-grating structures in the second grating region is in accordance with the following mathematical formula: $.Math.=o\frac{\lambda }{2*n_{\mathrm{eff}}}.$
Wherein, Λ is the length of grating period, λ is the wavelength of the laser light, n.sub.eff is the equivalent refractive index of semiconductor waveguide, m=1, and o=2. The first grating region is a first-order grating region, and the second grating region is a second-order grating region, so as to form a hybrid grating structure in the grating layer. The surface emitting laser emits laser light perpendicularly from a light-emitting surface defined by the second grating region.

An optical semiconductor device of the present disclosure comprises: a ridge structure formed on a first-conductivity-type semiconductor substrate; a buried layer buried on both side surfaces of the ridge structure; a second-conductivity-type second cladding layer and a second-conductivity-type contact layer laminated on the top of the ridge structure and the surface of the buried layer; a stripe-shaped mesa structure formed of a mesa reaching from the second-conductivity-type contact layer to the first-conductivity-type semiconductor substrate; a heat dissipation layer formed on the surface of the second-conductivity-type contact layer; a mesa protective film covering both side surfaces of the mesa structure and both end portions of the surface of the second-conductivity-type contact layer; and a second-conductivity-type-side electrode electrically connected to the second-conductivity-type contact layer.