Abstract: A surface-emitting semiconductor laser device that includes an edge-emitting laser formed in layers of semiconductor material disposed on a semiconductor substrate, a polymer material disposed on the substrate laterally adjacent the layers in which the edge-emitting laser is formed, a diffractive or refractive lens formed on an upper surface of the polymer material, a side reflector formed on an angled side reflector facet of the polymer material generally facing an exit end facet of the laser, and a lower reflector disposed on the substrate beneath the polymer material. Laser light passes out of the exit end facet and propagates through the polymer material before being reflected by the side reflector toward the lower reflector. The laser light is then re-reflected by the lower reflector towards the lens, which directs the laser light out the device in a direction that is generally normal to the upper surface of the substrate.

Abstract: An 830 nm broad area semiconductor laser having a distributed Bragg reflector (DBR) structure. The semiconductor laser supports multiple horizontal transverse modes of oscillation extending within a plane perpendicular to a crystal growth direction of the laser, in a direction perpendicular to the length of the resonator of the laser. The resonator includes a diffraction grating in the vicinity of the emitting facet of the laser. The width of the diffraction grating in a plane perpendicular to the growth direction and perpendicular to the length of the resonator is different at first and second locations along the length of the resonator. The width of the diffraction grating along a direction which is perpendicular to the length of the resonator increases with increasing distance from the front facet of the semiconductor laser.

Abstract: A VCSEL includes a grating layer configured with a non-periodic, sub-wavelength grating, in which the non-periodic, sub-wavelength grating includes at least one first section configured to have a relatively low reflection coefficient and at least one second section configured to have a relatively high reflection coefficient to cause light to be reflected in a predetermined, non-Gaussian, spatial mode across the sub-wavelength grating. The VCSEL also includes a reflective layer and a light emitting layer disposed between the grating layer and the reflector, in which the sub-wavelength grating and the reflector form a resonant cavity.

Abstract: The present invention provides a QCL device with an electrically controlled refractive index through the Stark effect. By changing the electric field in the active area, the energy spacing between the lasing energy levels may be changed and, hence, the effective refractive index in the spectral region near the laser wavelength may be controlled.

Abstract: A semiconductor device is provided that has a VCSEL and a protection diode integrated therein and that has an additional intrinsic layer. The inclusion of the additional intrinsic layer increases the width of the depletion region of the protection diode, which reduces the amount of capacitance that is introduced by the protection diode. Reducing the amount of capacitance that is introduced by the protection diode allows the VCSEL to operate at higher speeds.

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 an optical modulator optically coupled to the gain medium, a phase modulator optically coupled to the optical modulator, and a waveguide disposed in the substrate and optically coupled to the gain medium. The tunable laser further includes a first wavelength selective element characterized by a first reflectance spectrum and disposed in the substrate, a second wavelength selective element characterized by a second reflectance spectrum and disposed in the substrate, 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: A semiconductor laser module includes a semiconductor laser unit and a light selecting unit. The semiconductor laser unit includes a semiconductor laser substrate and a plurality of distributed reflector semiconductor laser devices formed on the semiconductor laser substrate in an array. Each of the distributed reflector semiconductor laser devices is configured to emit a laser light of a different wavelength from an output facet. The light selecting unit includes a light selecting device substrate and a light selecting device formed on the light selecting device substrate. The light selecting device is configured to selectively output a laser light emitted from a distributed reflector semiconductor laser device. The semiconductor laser unit and the light selecting unit are attached to each other in such a manner that the light selecting device is optically coupled to the distributed reflector semiconductor laser devices.

Abstract: The illustrated embodiments provide a system and a method of manufacture for a complex-coupled distributed feedback laser diode. The improved laser diode has a complex-coupled metal grating to enforce the laser to emit in a longitudinal single-frequency and suppress dynamical instabilities. In addition, the improved device uses a transparent conductive cladding layer over the metal grating and makes therefore the need for re-growth redundant.

Abstract: A surface emitting laser array element is disclosed that includes a lower distributed bragg reflector (DBR) that is formed on a substrate, an active layer that is formed on the lower DBR, and an upper DBR that is formed on the active layer. A mesa and a dummy mesa that is arranged at a periphery of the mesa are created by removing a portion of the upper DBR. The mesa forms a surface emitting laser, and a wiring is connected to an electrode that is formed on an upper face of the mesa. The wiring includes a portion that is arranged over an upper face of the dummy mesa, a side face of the dummy mesa, and a bottom face at a peripheral region of the dummy mesa extending along a longitudinal direction of the wiring.

Abstract: An imaging panel includes a light source, a reflective image-forming array, and a freeform-prism eyepiece. The light source includes a light emitter and a waveguide having a grating. The waveguide is configured to confine the light from the light emitter and to release the light through the grating. The reflective image-forming array is configured to form a display image using light from the light source and to reflect the display image back through the waveguide. The freeform-prism eyepiece configured to receive the display image and to present the display image for viewing, together with an external image transmitted through the eyepiece.

Abstract: An external cavity laser array system may be used in a WDM optical system, such as a WDM-PON, for transmitting optical signals at multiple channel wavelengths. The system generally includes a plurality of laser emitters (e.g., gain chips) optically coupled to and separated from respective exit reflectors (e.g., tunable narrow-band reflectors), thereby forming an array of external cavity lasers with extended lasing cavities. The exit reflectors may be distributed Bragg reflectors (DBRs) located in the waveguides in an arrayed waveguide grating (AWG). The laser emitters emit a range of wavelengths including multiple channel wavelengths and the DBRs reflect a subset of channel wavelengths including at least a channel wavelength associated with the laser emitter such that lasing occurs at the subset of channel wavelengths. The AWG then filters the emitted laser light at the associated channel wavelengths.

Abstract: A laser diode with which separation of a current narrowing layer is able to be prevented is provided. The laser diode includes a mesa that has a first multilayer film reflector, an active layer, and a second multilayer film reflector in this order, and has a current narrowing layer for narrowing a current injected into the active layer and a buffer layer adjacent to the current narrowing layer. The current narrowing layer is formed by oxidizing a first oxidized layer containing Al. The buffer layer is formed by oxidizing a second oxidized layer whose material and a thickness are selected so that an oxidation rate is higher than that of the first multilayer film reflector and the second multilayer film reflector and is lower than that of the first oxidized layer. A thickness of the buffer layer is 10 nm or more.

Abstract: A multiwavelength optical device includes a substrate; a first mirror section including a plurality of first mirror layers stacked on the substrate; an active layer stacked on the first mirror section, the active layer including a light emission portion; a second mirror section including a plurality of second mirror layers stacked on the active layer; a first electrode disposed between the active layer and the second mirror section; and a second electrode disposed between the first mirror section and the active layer.

Abstract: A surface emitting laser device includes a substrate and plural semiconductor layers laminated on the substrate, the plural semiconductor layers including a first semiconductor multi-layer film including aluminum (Al), an active layer, and a second semiconductor multi-layer film, a light emitting section having a mesa structure being formed on the first semiconductor multi-layer film. When viewed in a direction orthogonal to a surface of the substrate, an outer shape of the first semiconductor multi-layer film is a macroscopically smooth shape without an angular corner, and a side surface of the first semiconductor multi-layer film is coated with a passivation film and a protection film.

Abstract: To provide a small and lightweight organic laser device which can be manufactured in a reproductive manner and from which laser light with a desired wavelength can be obtained. A first substrate provided with a light-emitting element having a light-emitting layer between a pair of electrodes and a second substrate provided with a laser medium including a laser dye face each other and one of the pair of electrodes, which is placed between the light-emitting layer and the laser medium, has a light transmitting property. With such a structure, a laser device with which a laser medium and a light source are integrated can be provided.

Abstract: A surface emitting laser is formed of a composition in which bandgap energy of layers from immediately above a current confinement layer to a second conductivity type contact layer is reduced towards the second conductivity type contact layer in a stacking direction, and a composition in which bandgap energy of layers from immediately below the current confinement layer to a first conductivity type contact layer is reduced towards the first conductivity type contact layer in a stacking direction while bypassing a quantum well layer or a quantum dot of an active layer, and includes a second conductivity type cladding layer including a material for reducing the mobility of carriers.

Abstract: Method for suppressing side modes during use of a tunable laser of MGY type, having an amplification section, a phase section and a reflector section having a Y-branched waveguide, with a first a second branch, where the laser operation point is defined by feeding a respective current through the phase section, the first and the second branch, where possible combinations of these currents span a three-dimensional space, in which elongated volumes define combinations of currents for which the laser is operated in the same mode and where two-dimensional sections, defined by holding the current through the phase section constant and varying the currents through the branches, through a certain of the volumes constitute modeflats.

Abstract: Enhanced reflectivity High-Contrast Gratings are described which operate in different medium. An HCG is described with a deep/buried metallization layer separated at a distance of least three to four grating thicknesses from the grating. Reflective bandwidth of the HCG is substantially increased, such as by a factor or five, by inclusion of the deep/buried metallization layer. An HCG is described which provides high reflectivity, even when embedded into materials of a moderate to high index of refraction, such as semiconductor material. Vertical cavity surface emitting laser embodiments are described which utilize these reflectivity enhancements, and preferably utilize HCG reflectors for top and/or bottom mirrors.

Abstract: A semiconductor laser includes a light emission end facet; a first optical waveguide extending in a predetermined optical-axis direction, the first optical waveguide being optically coupled to the light emission end facet; a ring resonator having a plurality of periodic transmittance peak wavelengths, the ring resonator being optically coupled to the first optical waveguide; a plurality of gain waveguides that generate light by injection of current; an optical coupler portion that optically couples the first optical waveguide to each of the plurality of gain waveguides; and a plurality of second optical waveguides including diffraction gratings, the plurality of second optical waveguides being respectively optically coupled to the plurality of gain waveguides. Also, each of the diffraction gratings in the plurality of second optical waveguides has a different reflection band.

Abstract: A semiconductor device is provided that has a VCSEL and a protection diode integrated therein and that has an additional intrinsic layer. The inclusion of the additional intrinsic layer increases the width of the depletion region of the protection diode, which reduces the amount of capacitance that is introduced by the protection diode. Reducing the amount of capacitance that is introduced by the protection diode allows the VCSEL to operate at higher speeds.

Abstract: Methods for fabricating an optical device that exhibits improved conduction and reflectivity, and minimized absorption. Steps include forming a plurality of mirror periods designed to reflect an optical field having peaks and nulls. The formation of a portion of the plurality of minor periods includes forming a first layer having a thickness of less than one-quarter wavelength of the optical field; forming a first compositional ramp on the first layer; and forming a second layer on the compositional ramp, the second layer having a different index of refraction than the first layer and having a thickness such that the nulls of the optical field occur within the second layer and not within the compositional ramp, and wherein forming the second layer further comprises heavily doping the second layer at a location of the nulls of the optical field.

Abstract: A semiconductor laser device includes a first semiconductor stack portion that includes a grating layer and an active layer provided on the grating layer. The grating layer has a first region and second region; a diffraction grating provided in the first region; a semiconductor ridge structure portion provided on the first semiconductor stack portion and extending in a first direction; and a pair of first trenches provided along both side faces of the semiconductor ridge structure portion with the first region of the grating layer being located between the trenches. The first trenches penetrate through the grating layer. The first region of the grating layer has an end extending in a second direction intersecting with the first direction. The end of the first region of the grating layer reaches a trench.

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: In one example embodiment, a DFB laser includes a substrate, an active region positioned above the substrate, and a grating layer positioned above the active region. The grating layer includes a portion that serves as a primary etch stop layer. The DFB laser also includes a secondary etch stop layer located either above or below the grating layer, and a spacer layer interposed between the grating layer and the active region.

Abstract: Included are: an active layer provided between an upper multilayer film reflecting mirror and a lower multilayer film reflecting mirror formed on a GaAs substrate and formed of a periodic structure of a low-refractive-index layer formed of AlxGa1-xAs (0.8?x?1) and a high-refractive-index layer formed of AlyGa1-yAs (0?y?x), at least one of the low-refractive-index layer and the high-refractive-index layer being of n-type; and a lower electrode provided between the lower multilayer film reflecting mirror and the active layer and configured to inject an electric current into the active layer.

Abstract: A semiconductor optical amplifier includes a semiconductor substrate; an optical waveguide that includes an active layer formed on the semiconductor substrate; and a wavelength selective reflection film that is formed on an end face where signal light is incident on the optical waveguide the wavelength selective reflection film allows transmission of the signal light, and reflects light of any wavelength other than the signal light.

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 laser device includes a substrate, a lower cladding layer on the substrate, an active layer on the lower cladding layer and having a disordered portion spaced from an end face of a resonator of the laser device, an upper cladding layer located on the active layer, and a diffraction grating located in a portion of a layer lying above or below the active layer, with respect to the substrate. The disordered portion intersects a boundary between a diffraction grating section, in which the diffraction grating is located, and a bulk section, in which no diffraction grating is located.

Abstract: A semiconductor laser includes: a first portion, made from a silicon-containing material, including an optical waveguide, a first diffraction grating including a phase shift, and a second diffraction grating; a second portion including a light-emitting layer made from a material different from that of the first portion; a laser region including the first diffraction grating, and the optical waveguide and the light-emitting layer provided in a position corresponding to the first diffraction grating; and a mirror region including the second diffraction grating, and the optical waveguide and the light-emitting layer provided in a position corresponding to the second diffraction grating.

Abstract: The objective of the invention is to provide a photonic crystal device which enables efficient confinement of carriers while preventing the deterioration of device characteristics. Specifically a photonic crystal device has a photonic crystal in which media with different refractive indexes are regularly arranged, wherein an active region (11) includes an active layer (12) and carrier confinement layers (13, 14) provided on the top and bottom of the active layer (12) respectively for confining carriers. The photonic crystal is formed by a buried growth layer (15) with a larger bandgap than that of the active region (11).

Abstract: A Bragg grating has a local reflection strength which varies with position along the length of the grating so as to generate a non-uniform wavelength reflection spectrum, enabling compensation for a non-uniform gain profile of the gain section of a tunable laser. In another aspect, a Bragg comb grating is modulated by an envelope function which can also compensate for a non-uniform gain profile. The comb grating may be a phase change grating, with the envelope function shape being controlled by the length between phase changes and/or size of the phase changes.

Abstract: It is an object of the present invention to improve the confinement of the carriers within a VCSEL. As a general concept of the invention, it is proposed to integrate a phototransistor layer structure into the layer stack of the VCSEL.

Abstract: A wavelength tunable filter and a wavelength tunable laser module are a codirectional coupler type whose characteristics do not vary significantly with a process error. They are structured so as to include a semiconductor substrate which has a first optical waveguide and a second optical waveguide. The first and the second optical waveguides are extended from a first side of the semiconductor substrate to an opposing second side thereof. The first optical waveguide includes a first core layer, which has a planar layout having periodic convexes and concaves, and a pair of electrodes, which vertically sandwich the first core layer. The second optical waveguide includes a second core layer, which has a lower refractive index than the first core layer. Further, a layer having the same composition and film thickness as the second core layer is placed under the first core layer.

Abstract: A diode laser having aluminum-containing layers and a Bragg grating for stabilizing the emission wavelength achieves an improved output/efficiency. The growth process is divided into two steps for introducing the Bragg grating, wherein a continuous aluminum-free layer and an aluminum-free mask layer are continuously deposited after the first growth process such that the aluminum-containing layer is completely covered by the continuous aluminum-free layer. Structuring is performed outside the reactor without unwanted oxidation of the aluminum-containing semiconductor layer. Subsequently, the pre-structured semiconductor surface is further etched inside the reactor and the structuring is impressed into the aluminum-containing layer.

Abstract: A multi-wavelength laser array of a plurality of emitters in a diode bar or stack where each beam is deflected by a different angle to be incident upon a uniform volume holographic grating with a portion of the beam being deflected as a feedback portion while a further portion provides a wavelength tuned output unique to each emitter. The arrangement of a uniform volume holographic grating with deflectors such as phaseplates eliminates the need to use expensive wavelength chirped gratings.

Abstract: A laser structure is provided in which an influence caused by a concave-convex structure on laser characteristics is reduced when the Epitaxial Lateral Overgrowth (ELO) technique is applied to a photonic-crystal surface emitting laser. The laser structure includes a first layer, a second layer, a mask structure, a fourth layer, and a photonic crystal. An optical film thickness of the mask structure is not an integer multiple of a half of an oscillation wavelength ?, and reflectivity taken when laser light enters a multilayer structure including the first layer, the second layer, the mask structure, and the fourth layer from the fourth layer side is lower than reflectivity at an interface between the second layer and the first layer.

Abstract: A multi-wavelength distributed Bragg reflector (DBR) semiconductor laser is provided where DBR heating elements are positioned over the waveguide in the DBR section and define an interleaved temperature profile that generates multiple distinct reflection peaks corresponding to distinct temperature dependent Bragg wavelengths associated with the temperature profile. Neighboring pairs of heating elements of the DBR heating elements positioned over the waveguide in the DBR section are spaced along the direction of the axis of optical propagation by a distance that is equal to or greater than the laser chip thickness b to minimize the impact of thermal crosstalk between distinct temperature regions of the interleaved temperature profile.

Abstract: In accordance with one embodiment of the present disclosure, a DBR laser diode is provided where the wavelength selective grating of the laser diode is characterized by an aperiodically shifted grating phase ? and a Bragg wavelength ?B. The aperiodically shifted grating phase ? is substantially symmetric or substantially ?-shifted symmetric relative to a midpoint CL or shifted midpoint CL* of the DBR section. The phase ? of the wavelength selective grating is characterized by aperiodic phase jumps of magnitude ?J1, J2, . . . and segment lengths l0, 1, . . . . The phase jumps of the wavelength selective grating are arranged substantially symmetrically about a midpoint CL or shifted midpoint CL* of the DBR section along the optical axis of the DBR laser diode. At least two phase jumps reside on each side of the midpoint CL or shifted midpoint CL* of the DBR section.

Abstract: An optical image modulator and a method of manufacturing the same. The optical image modulator includes a substrate, an N electrode contact layer formed on the substrate, a lower distributed Bragg reflection (DBR) layer, a quantum well layer, an upper DBR layer, and a P electrode contact layer sequentially stacked on the N electrode contact layer, a P electrode formed on the P electrode contact layer, and an N electrode formed on the N electrode contact layer. The N electrode is a frame that surrounds the lower DBR layer.

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 semiconductor optical amplifier includes a semiconductor substrate; an optical waveguide that includes an active layer formed on the semiconductor substrate; and a wavelength selective reflection film that is formed on an end face where signal light is incident on the optical waveguide the wavelength selective reflection film allows transmission of the signal light, and reflects light of any wavelength other than the signal light.

Abstract: A semiconductor laser that includes a single mode semiconductor laser coupled to a flared power amplifier is provided, the device including an internal or an external optical element that reinforces the curved wave front of the flared section of the device through phase-matching. By reinforcing the curved wave front via phase-matching, the device is less susceptible to thermal and gain-index coupled perturbations, even at high output powers, resulting in higher beam quality. Exemplary phase-matching optical elements include a grating integrated into the flared amplifier section; an intra-cavity, externally positioned binary optical element; and an intra-cavity, externally positioned cylindrically curved optical element.

Abstract: In one general embodiment, a thin film structure includes a substrate; a first corrosion barrier layer above the substrate; a reflective layer above the first corrosion barrier layer, wherein the reflective layer comprises at least one repeating set of sub-layers, wherein one of the sub-layers of each set of sub-layers being of a corrodible material; and a second corrosion barrier layer above the reflective layer. In another general embodiment, a system includes an optical element having a thin film structure as recited above; and an image capture or spectrometer device. In a further general embodiment, a laser according to one embodiment includes a light source and the thin film structure as recited above.

Abstract: A surface emitting laser element includes a light emission part having a mesa structure. The light emission part includes a lower reflector; a resonator structure including an active layer; and an upper reflector. The lower reflector, the resonator structure and the upper reflector are laminated on a substrate. A peripheral part of a top surface of the mesa structure is covered by a dielectric layer that has a tapered surface such that a thickness decreases in a direction toward an outermost part, a taper angle of the tapered surface with respect to a surface of the substrate is smaller than a slope angle of a side wall of the mesa structure with respect to the surface of the substrate, and an end part of the dielectric layer coincides with an end part of the upper reflector.

Abstract: A three-terminal VCSEL is provided that has a reduced fall time that allows the VCSEL to be operated at higher speeds. Methods of operating the three-terminal VCSEL are also provided. The VCSEL can be operated at higher speeds without decreasing the optical output of the VCSEL when it is in the logical HIGH state.

Abstract: A surface-emission laser diode includes a GaAs substrate, a cavity region, and upper and lower reflectors provided at a top part and a bottom part of the cavity region, the upper reflector and/or the lower reflector including a semiconductor Bragg reflector, at least a part of the semiconductor distributed Bragg reflector includes a semiconductor layer containing Al, Ga and As as major components, there being provided, between the active layer and the semiconductor layer that contains Al, Ga and As as major components, a semiconductor layer containing Al, In and P as major components adjacent to the semiconductor layer that contains Al, Ga and As as major components, with an interface formed coincident to a location of a node of electric strength distribution.

Abstract: The present invention discloses a manufacturing method of vertical cavity surface emitting laser. The method includes following steps: providing a substrate; forming an epitaxial layer stack including an aluminum-rich layer; forming an ion-doping mask including a ring-shaped opening; doping ions in the epitaxial layer stack through the ring-shaped opening and forming a ring-shaped ion-doped region over the aluminum-rich layer; forming an etching mask on the ion-doping mask for covering the ring-shaped opening of the ion-doping mask; etching the epitaxial layer stack through the etching mask and ion-doping mask for forming an island platform; oxidizing the aluminum-rich layer for forming a ring-shaped oxidized region. In addition, the present invention also discloses a vertical cavity surface emitting laser manufactured by the above mentioned method.

Abstract: An embodiment of the invention relates to a device comprising a laser and a waveguide stripe or netlike hexagonal stripe structure, which allows propagation of multitude of the lateral modes in the waveguide stripe or stripe structure, wherein the waveguide stripe has at least one corrugated edge section along its longitudinal axis to provide preferable amplification of the fundamental lateral mode or in-phase supermode and to obtain high brightness of the emitted radiation.

Abstract: A semiconductor optical integrated device includes a substrate having a main surface with a first and second regions arranged along a waveguiding direction; a gain region including a first cladding layer, an active layer, and a second cladding layer arranged on the first region of the main surface; and a wavelength control region including a third cladding layer, an optical waveguide layer, and a fourth cladding layer arranged on the second region of the main surface and including a heater arranged along the optical waveguide layer. The substrate includes a through hole extending from a back surface of the substrate in the thickness direction and reaching the first region. A metal member is arranged in the through hole. The metal member extends from the back surface of the substrate in the thickness direction and is in contact with the first cladding layer.

Abstract: Planar lenses and reflectors are described comprising subwavelength high-contrast gratings (HCG) having high index of refraction grating elements spaced apart from one another in straight and/or curved segments and surrounded by low index material. The high-contrast grating is configured to receive an incident wave which excites multiple modes within the high-contrast grating and is focused for reflection and/or transmission by said high contrast grating. The width of the high contrast grating bars vary along a distribution direction of the grating bars which is perpendicular to the length of the grating bars and/or varies along the length of one or more grating bars to focus said reflection and/or transmission. The HCG is configured to provide double focusing, whose use is exemplified within a vertical cavity surface emitting laser (VCSEL) structure using focusing HCG structures for both the top and bottom mirrors.