Abstract: Provided are a frequency tunable terahertz transceiver and a method of manufacturing a dual wavelength laser. The frequency tunable terahertz transceiver includes: a dual wavelength laser including two distributed feedback lasers that are manufactured in one substrate and output optical signals of respectively different wavelengths; and an optical device receiving the outputted optical signals to generate a terahertz wave.

Abstract: A method for manufacturing an optically pumped surface-emitting semiconductor laser device, wherein a surface-emitting semiconductor laser layer sequence having a quantum confinement structure is applied onto a common substrate. The surface-emitting semiconductor laser layer sequence outside an intended laser region is removed and a region is exposed. An edge-emitting semiconductor layer sequence is applied onto the exposed region over the common substrate, wherein the exposed region is exposed via the removing step, and the exposed region is suitable for transmitting pump radiation into the quantum confinement structure. A current injection path is then formed in the edge-emitting semiconductor layer sequence.

Abstract: Distributed feedback-laser diodes are provided. The distributed feedback-laser diode may include a substrate, a lower cladding layer having a grating on the substrate, an active layer disposed on the lower cladding layer, a first upper cladding layer disposed on the active layer, a phase-shift region extending in a first direction on the first upper cladding layer, and a ridge waveguide layer extending in a second direction crossing the first direction on the phase-shift region.

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: 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: 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 high-efficiency laser diode is provided. Since a ?/4 phase-shifted distributed feedback (DFB) laser diode has a great coupling coefficient, mode stability is poor due to spatial hole burning when multiplication of the coupling coefficient by length of a resonator is equal to or greater than 2. In the inventive concept, a region capable of controlling spatial hole burning is inserted into a semiconductor laser diode structure. Thus, an ultrahigh-speed pulse laser diode having a repetition rate in the band ranging from 100 GHz to 300 GHz is obtained. In addition, a single-mode laser diode with improved energy use efficiency is implemented by changing the configuration of a laser diode.

Abstract: Techniques, devices and systems for optical communications based on wavelength division multiplexing (WDM) that use tunable multi-wavelength laser transmitter modules.

Abstract: A semiconductor laser that has a reflective surface. The reflective surface redirects the light of an edge emitting laser diode to emit from the top or bottom surface of the diode. The laser may include a gain layer and a feedback layer located within a semiconductive die. The gain and feedback layers generate a laser beam that travels parallel to the surface of the die. The reflective surface reflects the laser beam 90 degrees so that the beam emits the die from the top or bottom surface. The reflective surface can be formed by etching a vicinally oriented III-V semiconductive die so that the reflective surface extends along a (111)A crystalline plane of the die.

Abstract: An opto-electronic oscillator circuit, including: an opto-electronic circuit loop including an optical modulator that receives a first electrical signal and produces an optical output signal coupled with an optical resonator, a photodetector circuit optically coupled with the optical resonator, and a phase shifter coupled with the photodetector circuit for producing a phase shifted output signal that is fed back as the first electrical signal; an optical loop comprising the optical coupling of the optical resonator with the photodetector; and an electrical feedback circuit loop for coupling the first electrical signal with the photodetector circuit.

Abstract: A nitride semiconductor laser element includes a laminate. The laminate includes on a substrate a first conductivity type nitride semiconductor layer, an active layer, and a second conductivity type nitride semiconductor layer, and constitutes a cavity resonator. The laminate includes an element region, an exposed region and an island layer. The element region is a region in which the laser element is formed. The exposed region is a region in which at least the first conductivity type nitride semiconductor layer is exposed on both sides of the element region in the cavity direction, and which is provided continuously in a cavity resonating direction of the laser element. The island layer is separated from the element region by the exposed region, and that is disposed in a corner of the nitride semiconductor laser element.

Abstract: Methods and apparatus for improved single-mode selection in a quantum cascade laser. In one example, a distributed feedback grating incorporates both index-coupling and loss-coupling components. The loss-coupling component facilitates selection of one mode from two possible emission modes by periodically incorporating a thin layer of “lossy” semiconductor material on top of the active region to introduce a sufficiently large loss difference between the two modes. The lossy layer is doped to a level sufficient to induce considerable free-carrier absorption losses for one of the two modes while allowing sufficient gain for the other of the two modes. In alternative implementations, the highly-doped layer may be replaced by other low-dimensional structures such as quantum wells, quantum wires, and quantum dots with significant engineered intraband absorption to selectively increase the free-carrier absorption losses for one of multiple possible modes so as to facilitate single-mode operation.

Abstract: A wavelength tunable laser includes a DFB portion including a first optical waveguide provided with a first grating; a DBR portion including a second optical waveguide that is optically coupled to the first optical waveguide and is provided with a plurality of second gratings continuously arranged in a waveguide direction; and a phase shift portion including a third optical waveguide that is optically coupled to the first and second optical waveguides. Each of the second gratings has a grating formation area in which a grating is formed, and a grating phase shift area which shifts the phase of the grating adjacent thereto in the second grating.

Abstract: A photonic crystal surface emitting laser array reduces the occurrence of reflected feedback light while also reducing input of leaking light. The photonic crystal surface emitting laser array includes a plurality of first photonic crystal regions that cause laser oscillation, a second photonic crystal region that causes light diffraction to occur in an out-of-plane direction, and a light absorber that is provided above the second photonic crystal region and that absorbs light having a wavelength ?. A radiation coefficient of each first photonic crystal region is smaller than a radiation coefficient of the second photonic crystal region.

Abstract: A laser capable of emitting multiple laser beams is provided. A two-dimensional photonic crystal laser according to the present invention has a laminated structure including an active layer, a first photonic crystal layer having a periodic distribution of refractive index with a first period, and a second photonic crystal layer having a periodic distribution of refractive index with a second period that differs from the first period. This two-dimensional photonic crystal laser can emit a main beam traveling in a direction perpendicular to the two-dimensional photonic crystals and side beams each traveling in a direction inclined with respect to the main beam. These beams can be used, for example, in a recording/reproducing device by means of an optical disk, the main beam being used for recording/reproducing information and the side beams for following up the track.

Abstract: An integrated circuit die has a transistor circuitry section for implementing information handling operations. Optical circuitry is within the single semiconductor die. The optical circuitry includes a laser transmitter and is operably coupled to the transistor circuitry section. The transistor circuitry section originates information. The optical circuitry transmits the information in a laser beam through a wave guide to the edge of the integrated circuit die.

Abstract: Provided is a manufacturing method for an organic electroluminescence display apparatus in which processing uniformity is kept during partial removal processing of an electrode layer or an organic compound layer. The organic electroluminescence display apparatus includes: a substrate; and a light-emitting device including an organic compound layer including an emission layer sandwiched between electrodes formed on the substrate, in which: two or more of the light-emitting devices are provided, and the light-emitting devices are stacked in a direction perpendicular to the substrate; at least one of the electrodes and the organic compound layers in the two or more light-emitting devices includes openings; and the openings are positioned so as not to overlap with one another in the direction perpendicular to the substrate.

Abstract: Various embodiments of an optical switch device are provided. In one embodiment, the optical switch device includes a substrate. A photonic crystal, having a dielectric material, is applied on the substrate. An optical gain layer, having an optical gain material, is disposed above the photonic crystal. The photonic crystal is formed with a second-order distributed feedback structure to emit laser light perpendicular to a plane of the photonic crystal and a first-order distributed feedback structure adapted for reflecting light in the plane of the photonic crystal back into the second-order distributed feedback structure. The first-order distributed feedback structure at least one of fully surrounds the second-order distributed feedback structure and is arranged on two opposing edges of the second-order distributed feedback structure.

Abstract: Provided are an optical device including a multilayer reflector having a layer whose optical thickness is not ?/4, and a vertical cavity surface emitting laser using the optical device. A resonance frequency shift or a reduction in reflectivity which is caused by a deviation from an optical thickness of ?/4 can be suppressed to improve characteristics and yield. The optical device for generating light of a wavelength ? includes a reflector and an active layer. The reflector is a semiconductor multilayer reflector including a first layer and a second layer which are alternatively laminated and have different refractive indices. The first layer has an optical thickness smaller than ?/4. The second layer has an optical thickness larger than ?/4. The interface between the first layer and the second layer is located at neither a node nor an antinode of an optical intensity distribution within the reflector.

Abstract: A dual output laser source provided on a substrate outputs light from a first and second output. A portion of the light generated by the laser is supplied to a first modulator via the first output. A second portion of the light generated by the laser is supplied to a second modulator via the second output. The first modulator is provided on the substrate and generates a first modulated signal. The second modulator is also provided on the substrate and generates a second modulated signal. Each output of the laser is used to provide continuous wave light sources to components on photonic integrated circuit.

Abstract: Provided is a laser apparatus including: a DFB fiber laser 40 including, as an amplitude medium, a rare earth doped silica optical fiber codoped with a high concentration of aluminum; an optical feedback path 50 formed by a ring-shaped optical fiber; and an optical coupler 70 a) feeding back a part of an output of the DFB fiber laser 40 to the DFB fiber laser 40 via the optical feedback path 50, and b) outputting, to outside, another part of the output of the DFB fiber laser 40, where the optical fiber forming the optical feedback path 50 is longer than a length at which a relaxation oscillation noise in the output to the outside becomes ?110 dB/Hz.

Abstract: A large diameter optical waveguide, grating, and laser includes a waveguide having at least one core surrounded by a cladding, the core propagating light in substantially a few transverse spatial modes; and having an outer waveguide dimension of said waveguide being greater than about 0.3 mm. At least one Bragg grating may be impressed in the waveguide. The waveguide may be axially compressed which causes the length of the waveguide to decrease without buckling. The waveguide may be used for any application where a waveguide needs to be compression tuned. Also, the waveguide exhibits lower mode coupling from the core to the cladding and allows for higher optical power to be used when writing gratings without damaging the waveguide. The waveguide may resemble a short “block” or a longer “cane” type, depending on the application and dimensions used.

Abstract: Provided are a dual mode semiconductor laser and a terahertz wave apparatus using the same. The dual mode semiconductor laser includes a distributed feedback laser structure section including a first diffraction grating on a substrate and a distributed Bragg reflector laser structure section including a second diffraction grating on the substrate. A first wavelength oscillated by the distributed feedback laser structure section and a second wavelength oscillated by the distributed Bragg reflector laser structure section are different from each other, and the distributed feedback laser structure section and the distributed Bragg reflector laser structure section share the same gain medium with each other.

Abstract: A gain-coupled distributed feedback (DFB) semiconductor laser includes a grating formed by grooves through at least a part of an active region of a laser cavity. The DFB laser may be configured with a substantially pure gain-coupled grating and may be configured to provide facet power asymmetry. The grating may include at least a first-order grating section and a second-order grating section. A lasing wavelength may be obtained at the Bragg wavelength of the second-order grating section by substantially eliminating index coupling in the grating. The first-order grating section may act as a reflector for the lasing wavelength, thereby producing asymmetric power distribution in the laser cavity.

Abstract: Displays such as LCD panels are illuminated using frequency-doubled vertical extended cavity surface emitting lasers (VECSELs) as efficient light sources. Visible light from the VECSELs are directed to an illuminating panel using optical fibers and/or optical gratings to provide substantially uniform illumination of the illuminating panel. Visible light from the illuminating panel, which can be provided at a particular number of primary wavelengths by the VECSELs, is then used to illuminate the display.

Abstract: A DFB quantum cascade laser element that can reliably CW-oscillate a single-mode light even at room temperature or a temperature in proximity thereof is provided. In a quantum cascade laser element 1, a top-grating approach for which a diffraction grating 7 is formed on a laminate 3 is adopted, and thus in comparison with a buried-grating approach, deterioration in temperature characteristics of the laser element and decline in the yield and reproducibility are suppressed. In addition, since the thickness of a cladding layer 5 located between an active layer 4 and the diffraction grating 7 is within a range of 42±10% of the oscillation wavelength, weakening of light seeping from the active layer 4 to the diffraction grating 7 or an increase in light leakage is prevented. Consequently, by the quantum cascade laser element 1, a single-mode light can be reliably CW-oscillated even at room temperature or a temperature in proximity thereof.

Abstract: Provided is a laser module. The laser module comprises: a substrate; an gain unit oscillating a laser light on the substrate; an external resonance reflecting unit total-reflecting the laser light at an external of the substrate adjacent to one side of the gain unit; and an inner resonance reflecting unit reflecting the laser light to the external resonance reflecting unit at the substrate between the modulating unit and gain unit and outputting the laser light to the modulating unit.

Abstract: An optical device includes an optical fiber having a core including multicomponent phosphate glasses, and a cladding surrounding the core, and a first fiber Bragg grating formed in a first portion of the core of the optical fiber and having an index modulation amplitude greater than 2×10?5.

Abstract: Objects are achieved by an optical semiconductor device comprising: a structure 61 including a substrate 50, a diffraction grating 52a, an active layer 54 and a refractive index control layer 60; and an laser element 100 including an electrode 92a for the active layer, an electrode 92b for the refractive index control layer and an electrode 92c for switching, wherein a pre-bias current is previously supplied from the electrode 92a for the active layer to the active layer 54 in a state where a switching current is not supplied from the electrode 92c for switching to the active layer 54, and then while a current Idrive for activation is supplied from the electrode 92a for the active layer to the active layer 54, the laser element 100 is turned on by supplying the switching current Isw from the electrode 92c for switching to a part of the active layer 54, as well as turning off the laser element 100 by halting the supply of the switching current Isw.

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 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: A semiconductor laser outputs a laser light from an output facet of a waveguide having an index waveguide structure, via a lens system. The waveguide includes, in order from a rear facet opposite to the output facet, a first narrow portion, a wide portion that is wider than the first narrow portion, a second narrow portion narrower than the wide portion, a first tapered portion formed between the first narrow portion and the wide portion, which expands toward the wide portion, and a second tapered portion formed between the wide portion and the second narrow portion, which narrows toward the second narrow portion. Each of the first narrow portion, the wide portion, and the second narrow potion has a uniform width.

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 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: 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: A tunable diode laser system with external resonator in Littrow or Littman configuration has an optical lattice on which the light beam from a laser diode is diffracted, a support element to hold the lattice or to hold a mirror, which reflects the light diffracted by the lattice, and an actuator to change the position of the lattice or the mirror. The tunable diode laser system enables a reliable mode-hop-free tuning and furthermore is easy and economical to realize by having the support element include a carrier, on which the lattice or the mirror is arranged, and a base body, while the actuator acts on the carrier and rests against the base body. The carrier is connected to the base body via linkages, such that a linear deflection of the actuator is transformed into a rotation of the carrier in the plane of the light beam, while the center of rotation lies outside the base body.

Abstract: Provided is a high-output surface-emitting laser capable of reducing effects on reflectance of an upper reflection mirror in a single transverse mode. The surface-emitting laser includes plural semiconductor layers, laminated on a substrate, which includes a lower semiconductor multilayer reflection mirror, an active layer, and an upper semiconductor multilayer reflection mirror, wherein the lower or upper semiconductor multilayer reflection mirror includes a first semiconductor layer having a two-dimensional photonic crystal structure comprised of a high and low refractive index portions which are arranged in a direction parallel to the substrate, and wherein a second semiconductor layer laminated on the first semiconductor layer includes a microhole which reaches the low refractive index portion, the cross section of the microhole in the direction parallel to the substrate being smaller than the cross section of the low refractive index portion formed in the first semiconductor 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 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: It is an object of the present invention to realize a low cost laser light source capable of emitting several mW optical power while the operation current is reduced. In particular, the present invention concerns a 1.3 ?m wavelength band laser device suitable for several to several ten km short distance fiber optic transmission and also a less power consuming optical communication module in which such a laser is preferably mounted. As a laser structure which eliminates the necessity of adding an optical isolator by providing improved immunity to reflected light while lowering the operation current for less power consumption and not lowering the response speed, a short cavity laser which operates in multiple longitudinal modes is introduced. Especially, an angled mirror structure is formed at the laser's emitting edge to change the optical output direction so that the light is emitted from the top or bottom of the substrate.

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: In one example, a DFB laser includes a substrate, an active region, and a grating. The active region is formed above the substrate and is designed to emit light having a gain peak wavelength. The grating is formed above the active region and is designed to provide optical feedback for light having a lasing peak wavelength. The gain peak wavelength is longer than the lasing peak wavelength and a difference between the gain peak wavelength and the lasing peak wavelength at room temperature is between 10 nm and 50 nm.

Abstract: A surface-emitting photonic device including a structure disposed therein to enhance a performance thereof. The structure includes a two dimensionally periodic second order distributed feedback device (DFB) to emit diffraction limited outcoupled laser light having a predetermined wavelength along a propagation direction that is substantially normal to a plane of the DFB, and a first order distributed Bragg reflector (DBR) coplanar with, adjacent to and surrounding the DFB, a geometry of the DBR being selected such that a bandgap of the DBR is maximized and centered around the predetermined wavelength of the emitted light, a substrate, and either an optical gain layer, or a semi-conductor quantum well laser disposed within the substrate.

Abstract: A laser is disclosed including a gain section having a distributed feedback grating imposed thereon. An absorption section is embedded in the gain section such that the first and second portions of the distributed feedback grating extend on either side of the electro-absorption section. A controller imposes a substantially DC bias signal on the first and second gain electrodes and imposes a modulation signal encoding digital data on the modulation electrode to generate a frequency modulated signal. In some embodiments, the first and second portions are biased above the lasing threshold and the absorption section is modulated below the lasing threshold to modulate loss in the absorption section.

Abstract: In the surface emitting laser, low threshold electric current and high-power output are achieved while maintaining single mode characteristics. The surface emitting laser comprises a layered structure formed on a GaAs substrate 10 is comprised of: a semiconductor lower DBR mirror 12, a cladding layer 14, a n-type contact layer 16, an active layer 18, an electric current constricting layer 20, a p-type cladding layer 22, a p-type contact layer 24, a phase adjusting layer 36 and a dielectric upper DBR mirror 28. The surface emitting laser should be formed such that the diameter X (?m) of the opening diameter of the previously mentioned electric current constricting layer 20 and diameter Y (?m) of the phase adjusting layer satisfy the following relation: X+1.9??Y?X+5.0? (wherein ? indicates oscillation wavelength (?m) of the surface emitting laser).

Abstract: To provide an oscillation device having a long oscillation wavelength in which wavelength variable width is relatively broad and wavelength sweep rate is relatively high. An oscillation device includes a gain medium having a gain with respect to an electromagnetic wave to be oscillated, cavity structures for resonating the electromagnetic wave, and energy injection means and for injecting pumping energy into the gain medium. The gain medium is sandwiched between a first negative permittivity medium and a second magnetic permittivity medium each of which real part of permittivity with respect to the electromagnetic wave is negative. Electric field application means is provided for at least one of the first negative permittivity medium and the second negative permittivity medium to apply an electric field for changing a depletion region formed at a boundary part with the gain medium.

Abstract: The invention relates to fabrication of VCSELs. It provides a method for fabricating a VCSEL that contains a micro/nano-structured mode selective lateral layer, where the micro/nano-structured layer is obtained by well controlled local etching. The invention enables control of the micro/nano-structured layer thickness with very high precision. In particular, the invention relates to a method for fabricating a VCSEL with a micro/nano-structured mode selective layer for controlling the VCSELs transverse electromagnetic modes.

Abstract: Using sampled Bragg grating structure, the present invention proposes a distributed feedback (DFB) semiconductor laser based on reconstruction-equivalent-chirp technology. Namely, the Bragg grating in the said DFB semiconductor laser cavity is a sampled Bragg grating, in which there is an equivalent grating corresponding to the original ordinary DFB grating as feedback for lasing. The laser wavelength of the said semiconductor laser located within the operation bandwidth of the said equivalent grating. The said equivalent grating is designed and fabricated using REC technology and has equivalent chirps, one equivalent phase shift or multiple equivalent phase shifts. The said sampled Bragg grating has multiple ghost gratings and the wavelength spacing between neighboring ghost gratings is inversely proportional to the sampling period and the effective refractive index of the said semiconductor laser.

Abstract: A CS optical pulse train generation method, which is able to change the half width of an optical pulse constituting a CS optical pulse train, and which is compact and has low power consumption. A distributed Bragg reflector semiconductor laser utilized in this method is one which is constituted comprising an optical modulation region, a gain region, a phase control region, and a distributed Bragg reflector region. Current is injected into the gain region by way of a p-side electrode and a n-side common electrode by a constant current source, forming the population inversion required for laser oscillation. Optical modulation required to manifest mode locking is carried out in the optical modulation region. A diffraction grating is formed in the distributed Bragg reflector region.