Abstract: A the vertical-cavity surface-emitting laser includes a stripe-shaped active medium (10) having an emission maximum at a first wavelength (?1), wherein a first reflector (18) is arranged below the stripe-shaped active medium (10) and a second reflector (20) is arranged above the stripe-shaped active medium (10), with the first reflector (18) facing the second reflector (20), wherein the first reflector (18) and a second reflector (20) have a reflectivity maximum in the region of the first wavelength (?1), wherein a third reflector (12) and a fourth reflector (13) are each arranged on a side above or next to the stripe-shaped active medium (10), wherein the third reflector (12) faces the fourth reflector (13), and wherein the third reflector (12) and the fourth reflector (13) have a reflectivity maximum in the region of a second wavelength (?2), wherein the first wavelength (?1)) is greater than the second wavelength (?2).

Abstract: A surface emitting semiconductor laser includes: a semiconductor substrate; a lower reflector that is formed on the semiconductor substrate and includes a semiconductor multilayer of a first conduction type; an upper reflector that is formed above the semiconductor substrate and includes a semiconductor multilayer of a second conduction type; an active region interposed between the lower reflector and the upper reflector; a current confining layer that is interposed between the lower reflector and the upper reflector and has a conductive region having an anisotropic shape in a plane perpendicular to an optical axis; and an electrode that is formed on the upper reflector and has an opening via which a laser beam is emitted, the opening having different edge shapes in directions of the anisotropic shape.

Abstract: The present invention relates to a method of manufacturing the light emitting component of a VECSEL and the corresponding VECSEL. In the method a layer stack (2) is epitaxially grown on a semiconductor substrate (1). The layer stack comprises an active region (4), an upper distributed Bragg reflector (5) and a n- or p-doped current injection layer (13) arranged between the active region (4) and the semiconductor substrate (1). A mechanical support (6) or submount is bonded to an upper side of the layer stack (2) and the semiconductor substrate (1) is subsequently removed. A metallization layer (7) is optionally deposited on the lower side of the layer stack (2) and an optically transparent substrate (8) is bonded to this lower side. The proposed method allows the manufacturing of such a component in a standard manner and results in a VECSEL with a homogenous current injection and high efficiency of heat dissipation.

Abstract: A Fiber Bragg grating is sliced into small segments (such as 1 mm in length), the sliced fiber Bragg grating segments are used as external cavities for lasers to stabilize their center wavelength. In one embodiment, a semiconductor laser has an anti-reflection coating on the front facet and a high reflectivity coating on the back facet, a sliced fiber Bragg grating is used as a partial reflection mirror to form a lasing cavity. Since the sliced fiber Bragg grating has a very small wavelength drift with temperature change, the semiconductor laser has a stable center wavelength output. In the other embodiment, a solid state laser has an anti-reflection coating on the front facet and a high reflectivity coating on the back facet, a sliced fiber Bragg grating is used as a partial reflection mirror to form a lasing cavity. The solid state laser has a stable center wavelength output.

Abstract: A semiconductor chip has at least two DFB etched facet laser cavities with one set of facets with AR coatings and a second set of etched facets with HR coatings that have a different relative position with respect to the gratings. This creates a difference in the phase between each of the etched facets and the gratings which changes the operational characteristics of the two laser cavities such that at least one of the lasers provides acceptable performance. As a result, the two cavity arrangement greatly improves the yield of the fabricated chips.

Abstract: A fiber laser light source is provided with a laser resonator including a pair of fiber gratings optically connected to a fiber in a state that the fiber is interposed between the paired fiber gratings. The reflection center wavelength of a laser-exit side fiber grating, out of the paired fiber gratings, lies in a wavelength range where the reflectance of a fiber grating, out of the paired fiber gratings, closer to the pump laser light source is not smaller than 80% but not larger than 98%.

Abstract: A laser diode includes a substrate having a lattice constant of GaAs or between GaAs and GaP, a first cladding layer of AlGaInP formed on the substrate, an active layer of GaInAsP formed on the first cladding layer, an etching stopper layer of GaInP formed on the active layer, a pair of current-blocking regions of AlGaInP formed on the etching stopper layer so as to define a strip region therebetween, an optical waveguide layer of AlGaInP formed on the pair of current-blocking regions so as to cover the etching stopper layer in the stripe region, and a second cladding layer of AlGaInP formed on the optical waveguide layer, wherein the current-blocking regions having an Al content substantially identical with an Al content of the second cladding layer.

Abstract: A semiconductor laser includes an active layer, a first GaAs layer formed on the active layer, the first GaAs layer including a plurality of recessed portions periodically arranged, each of the recessed portions including a bottom surface of a (100) crystal surface and a slope including a (111) A crystal surface at least in parts, the recessed portion being disposed in contact with each other or with a minimal gap between each of adjacent ones of the recessed portions, the width of the bottom surface being greater than the minimal gaps, an InGaP layer formed on the recessed portion, and a second GaAs layer formed on the InGaAs layer over the recessed portion.

Abstract: The present invention provides a fabrication method of coaxial line laser diodes and a coaxial lighting optical fiber which disperses and guides uniform emission of light from a coaxial line laser diode. The line coaxial laser diode can be extended at a greater length to generate more spontaneous emission photons which are emitted from an elongated tubular active layer. The active layer has a uniform built-in electric field to distribute uniform current therein to get higher quantum efficiency. The length of the coaxial laser diode can be increased through a VLSED method. A longer laser ingot can be produced and cut to a large number of coaxial laser diodes. This method can reduce the waste of cutting in the wafer process and get larger lighting areas. Both the coaxial line laser diode and the coaxial lighting optical fiber can be coupled to form a high efficiency white-emitting luminescence device.

Abstract: A polarization pinned vertical cavity surface emitting laser (VCSEL). A VCSEL designed to be polarization pinned includes an upper mirror. An active region is connected on the upper mirror. A lower mirror is connected to the active region. A grating layer is deposited to the upper mirror. The grating layer includes a low index of refraction layer formed by deposition on the upper mirror. The grating layer further includes a high index of refraction layer formed by deposition on the low index of refraction layer. A grating is formed into the grating layer.

Abstract: A semiconductor light emitting device includes a pump light source, a gain structure, and an out-coupling mirror. The gain structure is comprised of InGaN layers that have resonant excitation absorption at the pump wavelength. Light from the pump light source causes the gain structure to emit light, which is reflected by the out-coupling mirror back to the gain structure. A distributed Bragg reflector causes internal reflection within the gain structure. The out-coupling mirror permits light having sufficient energy to pass therethrough for use external to the device. A frequency doubling structure may be disposed between the gain structure and the out-coupling mirror. Output wavelengths in the deep-UV spectrum may be achieved.

Abstract: A laser-induced optical wiring apparatus includes a substrate, first and second light-reflecting members provided on the substrate separately from each other, an optical waveguide provided on the substrate for optically coupling the first and second light-reflecting members to form an optical resonator, a first optical gain member provided across the optical waveguide and forming a laser oscillator along with the first and second light-reflecting members, and a second optical gain member provided across the optical waveguide separately from the first optical gain member, and forming another laser oscillator along with the first and second light-reflecting members.

Abstract: A wavelength tunable laser according to the present invention includes a first facet and a second facet opposite the first facet, a reflective region provided adjacent to the second facet, and a gain region provided between the first facet and the reflective region. The reflective region has a plurality of reflection peak wavelengths that periodically vary at a predetermined wavelength interval. The first facet and the reflective region constitute a laser cavity. Furthermore, the gain region includes an active layer where light is generated, a diffraction grating layer having a diffraction grating whose grating pitch varies in a light propagation direction, a refractive-index control layer provided between the active layer and the diffraction grating layer, a first electrode for injecting current into the active layer, and a plurality of second electrodes arranged in the light propagation direction to inject current into the refractive-index control layer.

Abstract: An optoelectronic component includes an optical pump device including a first radiation-generating layer and a first radiation exit area at a top side of the pump device, wherein electromagnetic radiation generated during operation of the pump device is coupled out from the pump device through the first radiation exit area transversely and at least in part non-perpendicularly with respect to the first radiation-generating layer, and a surface emitting semiconductor laser chip including a reflective layer sequence including a Bragg mirror, and a second radiation-generating layer, wherein the surface emitting semiconductor laser chip is fixed to the top side of the pump device, and the reflective layer sequence is arranged between the first radiation exit area and the second radiation-generating layer.

Abstract: It is an object of the invention to provide a VCSEL having both a high beam quality or a low M2-factor, respectively, and a reduced mirror thickness which improves the heat dissipation due to the reduced thickness and the production cost. It is suggested to employ a Bragg-reflector in combination with a metal reflector terminating the distal side of the Bragg-reflector as seen from the laser cavity, wherein the metal reflector layer is localised at the centre around the optical axis.

Abstract: Non-rigidly coupled, overlapping, non-feedback optical systems for spatial filtering of Fourier transform optical patterns and image shape characterization comprises a first optical subsystem that includes a lens for focusing a polarized, coherent beam to a focal point, an image input device that spatially modulates phase positioned between the lens and the focal point, and a spatial filter at the Fourier transform pattern, and a second optical subsystem overlapping the first optical subsystem includes a projection lens and a detector. The second optical subsystem is optically coupled to the first optical subsystem.

Abstract: A vertical cavity surface emitting laser (VCSEL) includes a semiconductor substrate, a lower reflecting mirror formed on the semiconductor substrate, and a mesa structure. The mesa structure includes an active layer, a selective oxidization layer that includes a current confined structure, and an upper reflecting mirror. A lower electrode is connected to the semiconductor substrate, and an upper electrode is connected to the upper reflecting mirror. The VCSEL emits laser light perpendicularly to the plane of the semiconductor substrate when an electric current flows between the upper electrode and the lower electrode. The semiconductor substrate is inclined with respect to (100) plane. The active layer includes a quantum well layer having a compressive strain with respect to the substrate, and a spacer layer. The spacer layer has either a compressive strain or a tensile strain with respect to the semiconductor substrate.

Abstract: A semiconductor surface emitting optical amplifier chip utilizes a zigzag optical path within an optical amplifier chip. The zigzag optical path couples two or more gain elements. Each individual gain element has a circular aperture and includes a gain region and at least one distributed Bragg reflector. In one implementation the optical amplifier chip includes at least two gain elements that are spaced apart and have a fill factor no greater than 0.5. As a result the total optical gain may be increased. The optical amplifier chip may be operated as a superluminescent LED. Alternately, the optical amplifier chip may be used with external optical elements to form an extended cavity laser. Individual gain elements may be operated in a reverse biased mode to support gain-switching or mode-locking.

Abstract: A method of manufacturing a nitride semiconductor light emitting element includes: forming a stacked layer body of a nitride semiconductor having a second conductive-type layer, a light emitting layer, and a first conductive-type layer stacked on a growth substrate in this order; forming a first Bragg reflector made of a dielectric multilayer film above the first conductive-type layer; forming a first electrode over the first Bragg reflector with the first electrode being electrically connected to the first conductive-type layer; bonding the stacked layer body to a supporting substrate via the first Bragg reflector and the first electrode; removing the growth substrate from the stacked layer body to expose the second conductive-type layer; and forming over the exposed second conductive-type layer a second electrode and a second Bragg reflector made of a dielectric multilayer film so that the second Bragg reflector faces the first Bragg reflector across the stacked layer body.

Abstract: An optical semiconductor device includes a semiconductor laser, a first optical waveguide, an optical coupler for branching light guided from the semiconductor laser through the first optical waveguide into two lights, two second optical waveguides, diffraction gratings provided individually on the two second optical waveguides, and an optical detector for detecting light guided through one of the two diffraction gratings, and the components are provided on the same substrate. The optical semiconductor device is configured such that reflection returning lights from the diffraction gratings side to the semiconductor laser side interfere with each other and thereby extinguish each other at the optical coupler and the phases of the reflection returning lights from the diffraction gratings side are displaced from each other by ? at the optical coupler portion.

Abstract: A polymer film laser is provided that comprises a plurality of extruded polymer layers. The plurality of extruded polymer layers comprises a plurality of alternating dielectric layers of a first polymer material having a first refractive index and a second polymer material having second refractive index different than the first refractive index.

Abstract: Two-dimensional photonic crystal surface-emitting laser comprising a two-dimensional photonic crystal, having media different in refractive index arrayed in a two-dimensional cycle, disposed in the vicinity of an active layer that emits light by the injection of carriers, wherein the two-dimensional photonic crystal consists of square lattices having equal lattice constants in perpendicular directions, and a basic lattice consisting of a square with one medium as a vertex has an asymmetric refractive index distribution with respect to either one of the two diagonals of the basic lattice to thereby emit light in a constant polarizing direction.

Abstract: In a surface emitting laser element, on an inclined substrate, a resonator structural body including an active layer, and a lower semiconductor DBR and an upper semiconductor DBR sandwiching the resonator structural body are stacked. A shape of a current passing-through region in an oxide confinement structure of the upper semiconductor DBR is symmetrical to an axis passing through a center of the current passing-through region parallel to an X axis and symmetrical to an axis passing through the center of the current passing-through region parallel to a Y axis, and a thickness of an oxidized layer surrounding the current passing-through region is greater in the +Y direction than in the +X and ?X directions. An opening width of a light outputting section in the X axis direction is smaller than another opening width of the light outputting section in the Y axis direction.

Abstract: An optoelectronic device is provided. A light source emitter and a light source receiver are integrated in the device. The light source emitter is a Zn-diffused vertical cavity surface-emitting laser (VCSEL). The light source receiver is a uni-traveling-carrier photodiode (UTC-PD). With the VCSEL, a 10 Gb/s eye is opened under a small voltage and a small signal amplitude. With the UTC-PD, the 10 Gb/s eye is passed even under zero-bias. Thus, the optoelectronic device has a high speed and power consumption is saved.

Abstract: A method of manufacturing a laser diode array capable of inhibiting electric cross talk is provided. The method of manufacturing a laser diode array includes a processing step of forming a peel layer containing an oxidizable material and a vertical resonator structure over a first substrate sequentially from the first substrate side by crystal growth, and then selectively etching the peel layer and the vertical resonator structure to the first substrate, thereby processing into a columnar shape, a peeling step of oxidizing the peel layer from a side face, and then peeling the vertical resonator structure of columnar shape from the first substrate, and a rearrangement step of jointing a plurality of vertical resonator structures of columnar shape obtained by the peeling step to a surface of a metal layer of a second substrate formed with the metal layer on the surface.

Abstract: Provided are a hybrid laser diode for single mode operation, and a method for manufacturing the hybrid laser diode. The hybrid laser diode includes a silicon layer, an active pattern disposed on the silicon layer, and a bonding layer disposed between the silicon layer and the active pattern. Here, the bonding layer includes diffraction patterns constituting a Bragg grating.

Abstract: The present invention provides a surface-emission type semiconductor laser wherein an effective length of a cavity is reduced, thereby enabling to realize a higher-speed direct modulation. In the surface-emission type semiconductor laser according to the present invention, when supposing the optical path length (L) of a resonator part relative to a lasing wavelength ?0 to be given as 0.9×?0?L?1.1×?0, and denoting the refractive indexes of a high refractive index layer and a low refractive index layer of a dielectric DBR by nH1 and nL1; the average refractive index within an optical path length ?0/4 in the semiconductor in contact with the dielectric DBR by nS1; and the refractive indexes of the high refractive index layer and the low refractive index layer of a semiconductor DBR by nH2 and nL2, respective materials to be used are selected so as to satisfy the following conditions (1) and (2): nH1>f(nS1)nL12+g(nS1)nL1+h(nS1),??(1) where f(nS1)=0.0266 nS12?0.2407 nS1+0.6347; g(nS1)=?0.0508 nS12+0.

Abstract: An organic semiconductor laser, which is produced integrally with an electrically operable inorganic LED (1), and also the method for producing said laser.

Abstract: Light sources are disclosed. A disclosed light source includes a III-V based pump light source (170) that includes nitrogen and emits light at a first wavelength. The light source further includes a vertical cavity surface emitting laser (VCSEL) that converts at least a portion of the first wavelength light (174) emitted by the pump light source (170) to at least a partially coherent light at a second wavelength (176). The VCSEL includes first and second mirrors (120, 160) that form an optical cavity for light at the second wavelength. The first mirror (120) is substantially reflective at the second wavelength and includes a first multilayer stack. The second mirror (160) is substantially transmissive at the first wavelength and partially reflective and partially transmissive and the second wavelength. The second mirror includes a second multilayer stack.

Abstract: A method for introducing light into a waveguide formed on the upper surface of a microelectronics substrate, by means of a distributed feedback laser device formed by the association of an SOI-type structure having a portion forming said waveguide, of a stack of III-V semiconductor gain materials partially covering the waveguide, and of an optical grating, wherein the grating step is selected so that the optical power of the laser beam circulates in a loop from the III-V stack to the waveguide.

Abstract: A digital image projector includes a light assembly configured to project light along a light path from at least one laser array light source, the projected light having an overlapping far field illumination in a far field illumination portion of the light path; a temporally varying optical phase shifting device configured to be in the light path; an optical integrator configured to be in the light path; a spatial light modulator located downstream of the temporally varying optical phase shifting device and the optical integrator in the light path, the spatial light modulator configured to be located in the far field illumination portion of the light path; and projection optics located downstream of the spatial light modulator in the light path, the projection optics configured to direct substantially speckle free light from the spatial light modulator toward a display surface.

Abstract: Narrow surface corrugated gratings for integrated optical components and their method of manufacture. An embodiment includes a grating having a width narrower than a width of the waveguide on which the grating is formed. In accordance with certain embodiments of the present invention, masked photolithography is employed to form narrowed gratings having a desired grating strength. In an embodiment, an optical cavity of a laser is formed with a reflector grating having a width narrower than a width of the waveguide. In another embodiment an integrated optical communication system includes one or more narrow surface corrugated gratings.

Abstract: Disclosed is a distributed feedback semiconductor laser diode device capable of operating at a high output ratio of forward/backward optical power while ensuring satisfactory stability of single-mode oscillation. The distributed feedback semiconductor laser diode device is configured to include a diffraction grating formed in an optical waveguide thereof. In a partial region of the optical waveguide, there is formed an alternately repetitive pattern of a grating part possessing a distributive refractivity characteristic and a no-grating space part possessing a uniform refractivity characteristic. The no-grating space part possessing a uniform refractivity characteristic has an optical path length that is half an integral multiple of a wavelength of laser oscillation, and the grating part possessing a distributive refractivity characteristic includes at least five grating periods.

Abstract: There are provided a process for producing a semiconductor device and a semiconductor device which allow conductivity distribution to be formed without making refractive index distributed even in a material system of a semiconductor difficult to be subjected to ion implantation. The process for producing a semiconductor device includes the steps of forming a semiconductor layer containing a dopant; forming a concave and convex structure on the semiconductor layer by partially removing the semiconductor layer; and forming a conductivity distribution reflecting the concave and convex structure in the semiconductor layer by performing heat treatment on the semiconductor layer in which the concave and convex structure has been formed at a temperature at which a material forming the semiconductor layer causes mass transport and filling up a hole of a concave portion of the concave and convex structure with the material forming the semiconductor layer.

Abstract: The present invention relates to a method that involves providing a stack of a first substrate and a InGaN seed layer formed on the first substrate, growing an InGaN layer on the InGaN seed layer to obtain an InGaN-on-substrate structure, forming a first mirror layer overlaying the exposed surface of the grown InGaN layer, attaching a second substrate to the exposed surface of the mirror layer, detaching the first substrate from the InGaN seed layer and grown InGaN layer to expose a surface of the InGaN seed layer opposite the first mirror layer, and forming a second mirror layer overlaying the opposing surface of the InGaN seed layer.

Abstract: An integrated photonic circuit includes waveguides (12-19) and other photonic components. The photonic circuit has a first part (1) and a second part (2), the first part and the second part being connected to a mirror in the form of a half 2×2 multimode interferometer (MMI) (32), which comprises solely one half MMI (31) in a longitudinal direction, the half MMI (32) having two ports (33, 34) and being arranged to reflect half of the light that is incident on one of the ports to one port and transmit half of the incident light to the second port, and the free surface (35) of the half MMI (32) having been treated with a highly reflective material.

Abstract: A semiconductor laser includes a first optical confinement layer, a plurality of first quantum wires and buried semiconductor regions disposed on a first area, a plurality of second quantum wires and buried semiconductor regions disposed on a second area, an active layer disposed on a third area, and a second optical confinement layer. The plurality of first quantum wires and the buried semiconductor regions constitute a first distributed Bragg reflector, and the plurality of second quantum wires and the buried semiconductor regions constitute a second distributed Bragg reflector. The third area is disposed between the first area and the second area. The buried semiconductor regions have a refractive index different from the average refractive index of the first quantum wires and the average refractive index of the second quantum wires. These distributed Bragg reflectors form a DBR laser having a cavity length defined by the length of the active layer.

Abstract: A vertical cavity surface emitting laser diode (VCSEL) is disclosed, which reduces the light scattering by the step formed at the interface between the dielectric DBR and the semiconductor that reflects the mesa shape of the tunnel junction. The dielectric DBR of the invention includes a plurality of first films with relatively smaller refractive index and a plurality of second films with relatively larger refractive index. These first and second films are alternately stacked to each other to cause the periodic structure of the refractive indices. The VCSEL of the invention, different from the conventional device, provides the dielectric film with relatively larger refractive index that directly comes in contact with the semiconductor to set the node of the optical standing wave at the interface between the dielectric DBR and the semiconductor.

Abstract: A surface-emitting semiconductor laser is described, with a semiconductor chip (1), which has a substrate (2), a DBR-mirror (3) applied to the substrate (2) and an epitaxial layer sequence (4) applied to the DBR mirror (3), said layer sequence comprising a radiation-emitting active layer (5), and with an external resonator mirror (9) arranged outside the semiconductor chip (1). The DBR mirror (3) and the substrate (2) are partially transmissive for the radiation (6) emitted by the active layer (5) and the back (14) of the substrate (2) remote from the active layer (5) is reflective to the emitted radiation (6).

Abstract: A tunable distributed feedback semiconductor laser includes a substrate; an optical waveguide structure disposed on a main surface of the substrate and including an active layer and a diffraction grating, the optical waveguide structure being divided into a first DFB portion, a wavelength-tuning region, and a second DFB portion in that order; a first electrode for injecting carriers into the active layer in the first DFB portion; a second electrode for injecting carriers into the active layer in the second DFB portion; and a third electrode for supplying a wavelength tuning signal to the wavelength-tuning region. The diffraction grating extends over the first DFB portion, the wavelength-tuning region, and the second DFB portion. An optical confinement factor of the wavelength-tuning region is smaller than that of the first and second DFB portions.

Abstract: High-power, phased-locked, laser arrays as disclosed herein utilize a system of optical elements that may be external to the laser oscillator array. Such an external optical system may achieve mutually coherent operation of all the emitters in a laser array, and coherent combination of the output of all the lasers in the array into a single beam. Such an “external gain harness” system may include: an optical lens/mirror system that mixes the output of all the emitters in the array; a holographic optical element that combines the output of all the lasers in the array, and an output coupler that selects a single path for the combined output and also selects a common operating frequency for all the coupled gain regions.

Abstract: Various methods and apparatuses are described in which an array of optical gain mediums capable of lasing are contained in a single integral unit. The array may contain four or more optical gain mediums capable of lasing. Each optical gain medium capable of lasing supplies a separate optical signal containing a band of wavelengths different than the other optical gain mediums capable of lasing in the array to a first multiplexer/demultiplexer. A connection for an output fiber exists to route an optical signal to and from a passive optical network.

Abstract: A vertical-cavity, surface-emission-type laser diode includes an optical cavity formed of an active region sandwiched by upper and lower reflectors, wherein the lower reflector is formed of a distributed Bragg reflector and a non-optical recombination elimination layer is provided between an active layer in the active region and the lower reflector.

Abstract: When configuring a surface emitting laser by a semiconductor material not capable of largely extracting a refractive-index difference, the surface emitting laser using a photonic crystal capable of forming a waveguide is provided.

Abstract: An objective of the present invention is to provide a surface emitting laser capable of selectively generating a laser oscillation in the fundamental mode and thereby emitting a single-wavelength laser light. In a surface emitting laser including an active layer and a two-dimensional photonic crystal provided on one side of the active layer, a reflector 45 or 46 is provided at least at a portion of the circumference of the two-dimensional photonic crystal. The reflector has a reflectance distribution in which the reflectance has a maximum value at a position where the amplitude envelope of the fundamental mode of an internal resonance light created within the two-dimensional photonic crystal. This design strengthens the fundamental mode while suppressing the second mode, thus enabling the laser oscillation in the fundamental mode to be selectively obtained, so that a single-wavelength laser light can be emitted.

Abstract: A semiconductor diffraction grating device includes a semiconductor substrate having a principal surface, a semiconductor core layer and a semiconductor cladding layer provided on the principal surface, and a chirped grating structure provided between the semiconductor core layer and the semiconductor cladding layer. The chirped grating structure includes a first region, a second region, and a third region arranged in that order in a predetermined axis direction, the first, second, and third regions including a plurality of projections constituting a chirped grating. The plurality of projections are provided at placement positions arranged with a predetermined pitch in the predetermined axis direction. The coupling coefficient ? of the chirped grating monotonically increases in the predetermined axis direction to a predetermined value in the first region, remains flat in the second region, and monotonically decreases in the predetermined axis direction from the predetermined value in the third region.

Abstract: Provided is a multiple distributed feedback laser device which includes a first distributed feedback region, a modulation region, a second distributed feedback region, and an amplification region. An active layer is disposed on the substrate of the first distributed feedback region, the modulation region, the second distributed feedback region, and the amplification region. A first diffraction grating is disposed in the first distributed feedback region to be coupled to the active layer in the first distributed feedback region. A second diffraction grating is disposed in the second distributed feedback region to be coupled to the active layer in the second distributed feedback region. The multiple distributed feedback laser device further includes a first micro heater configured to supply heat to the first diffraction grating and a second micro heater configured to supply heat to the second diffraction grating.

Abstract: A structure including a Si1-xGex substrate and a distributed Bragg reflector layer disposed directly onto the substrate. The distributed Bragg reflector layer includes a repeating pattern that includes at least one aluminum nitride layer and a second layer having the general formula AlyGa1-yN. Another aspect of the present invention is various devices including this structure. Another aspect of the present invention is directed to a method of forming such a structure comprising providing a Si1-xGex substrate and depositing a distributed Bragg reflector layer directly onto the substrate. Another aspect of the present invention is directed to a photodetector or photovoltaic cell device, including a Si1-xGex substrate device, a group III-nitride device and contacts to provide a conductive path for a current generated across at least one of the Si1-xGex substrate device and the group III-nitride device upon incident light.

Abstract: A tunable laser includes a substrate comprising a silicon material and a gain medium coupled to the substrate. The gain medium includes a compound semiconductor material. The tunable laser also includes a waveguide disposed in the substrate and optically coupled to the gain medium, a first wavelength selective element characterized by a first reflectance spectrum and disposed in the substrate, and a second wavelength selective element characterized by a second reflectance spectrum and disposed in the substrate. The tunable laser further includes an optical coupler disposed in the substrate and joining the first wavelength selective element, the second wavelength selective element, and the waveguide and an output mirror.

Abstract: The present disclosure provides an approach to more efficiently amplify signals by matching either the gain materials or the pump profile with the signal profile for a higher-order mode (HOM) signal. By doing so, more efficient energy extraction is achieved.