Abstract: An electrostatic discharge (ESD) protected semiconductor device. The semiconductor device is formed as a monolithic structure. The monolithic structure includes a vertical cavity surface emitting laser (VCSEL) and a protection diode. The protection diode cathode is electrically coupled to the VCSEL anode and the protection diode anode is electrically coupled to the VCSEL cathode so as to provide ESD protection to the VCSEL.

Abstract: A detuned duo-cavity laser-modulator device and method are provided which include lower, middle and upper reflectors, a gain region and an absorber region integrated into a semiconductor die. The middle reflector is disposed between the lower and upper reflectors. Together, the lower and middle reflectors define a first resonant cavity, while the upper and middle reflectors define a second resonant cavity. A gain region is disposed within a laser cavity of the resonant cavities to generate an optical carrier wave, while an absorber region is disposed within a modulator cavity of the resonant cavities to modulate a signal on the optical carrier wave. The laser and modulator cavities are detuned resonant cavities, with the detuning of the laser and modulator cavities being selected to minimized change in reflection from the modulator cavity to the laser cavity when the absorber region modulates the signal on the optical carrier wave.

Abstract: A diffraction based overlay metrology system produces the overlay error independent of effects caused by local process variations. Generally, overlay patterns include process variations that provide spectral contributions, along with the overlay shift, to the measured overlay error. The contributions from process variations are removed from the determined overlay error. In one embodiment, the local process variations are removed by measuring the overlay pattern before and after the top diffraction gratings are formed. A plurality of differential spectra from the measurement locations of the completed overlay pattern can then be used with a plurality of ratios of differential spectra from measurement locations of the incomplete overlay pattern can then be used to determine the overlay error by either direct calculation or by fitting techniques. In another embodiment, the local process variations are removed with no premeasurement but with careful construction of the overlay patterns.

Abstract: A distributed Bragg reflector (DBR) includes a base substrate and a gain medium formed on the base substrate. A waveguide positioned above the base substrate in optical communication with the gain medium and defines a gap extending between the base substrate and the waveguide along a substantial portion of the length thereof. The waveguide may have a grating formed therein. A heating element is in thermal contact with the waveguide and electrically coupled to a controller configured to adjust optical properties of the waveguide by controlling power supplied to the heating element.

Abstract: An optoelectronic package having passive optical components that are configured to reduce the amount of optical back reflection that reaches an optoelectronic device housed within the optoelectronic package. In one example, the optoelectronic package includes an optoelectronic device, a wave plate, and a linear polarizer. The optoelectronic device is configured to emit an optical signal along an optical path. The wave plate is positioned in the optical path of the optoelectronic device. The linear polarizer is positioned in the optical path of the optoelectronic device between the optoelectronic device and the wave plate.

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 liquid crystal display includes a liquid crystal panel assembly with a plurality of pixels, a printed circuit board disposed under the liquid crystal panel assembly, and a plurality of laser diodes disposed on the printed circuit board. The laser diodes are disposed to correspond to substantially respective pixels of the liquid crystal panel assembly. In another embodiment, the liquid crystal display includes a light-guiding layer formed on the laser diodes.

Abstract: In a horizontal cavity surface emitted laser, there is provided a device structure that is capable of obtaining a circular narrow-divergence emitted beam that is high in the optical coupling efficiency with a fiber. As a first means, there is provided a horizontal cavity surface emitting laser having a structure in which the plane mirror that is inclined by 45° and the bottom lens of the oval configuration are integrally structured. As a second means, there is provided a horizontal cavity surface emitting laser in which the mirror having the columnar front surface configuration inclined by 45° and the bottom lens of the columnar front surface configuration are integrally structured. Since the horizontal component and the vertical component of the laser beam can be shaped, independently, through the above means. As a result, it is possible to obtain the circular narrow-divergence emitted beam.

Abstract: A semiconductor laser device includes a semiconductor laser portion, a window layer structure portion, a first inter-element portion, and a pre-placed optical element portion on an InP substrate. The semiconductor laser portion includes an InGaAsP layer and an InP layer located on the InGaAsP layer. The window layer structure portion of a double heterojunction structure has the same optical axis direction as the semiconductor laser portion and is located apart from the semiconductor laser portion. The first inter-element portion has a 100-?m or less thickness in an optical axis direction, is in contact with an end face on a side of the window layer structure portion adjacent to the semiconductor laser portion and includes an InGaAsP layer and an InP layer of the same layer configuration as the semiconductor laser portion.

Abstract: A semiconductor laser includes an optical waveguide formed on a semiconductor substrate and capable of generating gain by current injection, and a diffraction grating having a phase shift and provided along the optical waveguide over the overall length of the optical waveguide on the semiconductor substrate. The semiconductor laser is configured such that a Bragg wavelength in a region in the proximity of each of the opposite ends of the optical waveguide is longer than a Bragg wavelength in a region in the proximity of the phase shift in a state in which current injection is not performed for the optical waveguide.

Abstract: The invention is an organic laser apparatus including an organic compound that radiates laser light when current is injected. In an organic compound layer employed for the laser apparatus of the invention, a laminated structure and film thickness of each layer are determined in consideration of wavelength so as to radiate laser light. The organic compound layer collectively means each thin film containing mainly an organic compound formed between a pair of electrodes. The organic compound layer is formed so as to be sandwiched between a pair of electrodes and, preferably, formed by a plurality of layers each having a different carrier transport property and a different light emission wavelength. In addition, it is preferable to form a so-called resonator structure, in which a reflector is provided between the pair of electrodes.

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: An optical waveguide propagates a laser beam. Main diffraction grating and sub-diffraction grating couple light propagating in the optical waveguide. The main diffraction grating and the sub-diffraction grating couple the light in such a manner that propagation in a second order transverse mode of the light propagating in the optical waveguide when both the main diffraction grating and the sub-diffraction grating are disposed, is suppressed more than propagation in the second order transverse mode of the light propagating in the optical waveguide when only the main diffraction grating is disposed.

Abstract: Provided is a vertical cavity external surface emitting laser (VECSEL) apparatus in which incidence loss of a pumping beam can be reduced. The VECSEL apparatus includes: a laser chip including: an anti-reflection coating (ARC) layer to which a pumping beam is incident; a low Herpin Index distributed Bragg reflector (LHI-DBR) having a LHI stack structure; and a periodic gain layer that is formed on the LHI-DBR and generates laser light by being excited by the pumping beam; and an external cavity mirror that is installed outside the laser chip and faces the periodic gain layer and constitutes a laser cavity with the LHI-DBR.

Abstract: A device comprising a single photon generator and a waveguide, wherein a single photon generated by the single photon generator is coupled to the waveguide.

Abstract: A distributed Bragg reflector (DBR) includes a base substrate and a gain medium formed on the base substrate. A waveguide positioned above the base substrate in optical communication with the gain medium and defines a gap extending between the base substrate and the waveguide along a substantial portion of the length thereof The waveguide having a grating formed therein. A heating element is in thermal contact with the waveguide and electrically coupled to a controller electrically configured to adjust optical properties of the waveguide by controlling power supplied to the heating element.

Abstract: A surface-emitting type semiconductor laser includes a substrate; a first mirror disposed above the substrate; an active layer disposed above the first mirror; a second mirror disposed above the active layer; a first columnar section including the active layer, the first columnar section not having anisotropy; a first dielectric layer disposed in the first columnar section, the first dielectric layer including a symmetric opening section; a second columnar section disposed above the first columnar section, the second columnar section having an outer wall that has anisotropy; and a second dielectric layer disposed in the second columnar section, the second dielectric layer including an asymmetric opening section.

Abstract: A vertical cavity surface emitting laser device includes a first reflective mirror layer, a second reflective mirror layer, and an active layer disposed therebetween, wherein at least one of the first reflective mirror layer and the second reflective mirror layer includes a periodic-refractive-index structure in which the refractive index periodically changes in the in-plane direction and a part of the periodic-refractive-index structure includes a plurality of parts that disorder the periodicity.

Abstract: A near field optical apparatus comprising a conductive sheet or plane having an aperture therein with the conductive plane including at least one protrusion which extends into the aperture. The location, structure and configuration of the protrusion or protrusions can be controlled to provide desired near field localization of optical power output associated with the aperture. Preferably, the location, structure and configuration of the protrusion are tailored to maximize near field localization at generally the center of the aperture. The aperture preferably has a perimeter dimension which is substantially resonant with the output wavelength of the light source, or is otherwise able to support a standing wave of significant amplitude. The apparatus may be embodied in a vertical cavity surface emitting layer or VCSEL having enhanced nearfield brightness by providing a conductive layer on the laser emission facet, with, a protrusion of the conductive layer extending into an aperture in the emission facet.

Abstract: In one embodiment, a photo-darkening resistant optical fibre includes a waveguide having a numerical aperture less than 0.15. The waveguide includes a core having a refractive index n1 and a pedestal having a refractive index n2, and wherein the fibre includes a first cladding having a refractive index n3 surrounding the pedestal, wherein n1 is greater than n2, n2 is greater than n3. The core includes silica, a concentration of alumina of between approximately 0.3 to 0.8 mole percent, a concentration of phosphate of substantially 15 mole percent, a concentration of ytterbium substantially in the range 20000 to 45000 ppm. The pedestal can include silica, phosphate and germania. The core can have substantially zero thulium dopant.

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 distributed feedback semiconductor laser comprises a first cladding layer, a first optical guide layer, an active layer, a second optical guide layer, an InP semiconductor layer, an InGaAsP semiconductor layer, and a second cladding layer. The first optical guide layer is provided on the first cladding layer. The active layer is provided on the first optical guide layer. The second optical guide layer is provided on the active layer and made of AlGaInAs semiconductor. The InP semiconductor layer is provided on the second optical guide layer. The InGaAsP semiconductor layer is provided on the InP semiconductor layer. The second cladding layer is provided on the InGaAsP semiconductor layer and made of InP semiconductor. A diffraction grating for the distributed feedback semiconductor laser includes the InGaAsP semiconductor layer and the second cladding layer.

Abstract: An optical semiconductor device includes an optical semiconductor element, a metal pattern and at least one thermal conductive material. The optical semiconductor element has a first optical waveguide region and a second optical waveguide region. The second optical waveguide region is optically coupled to the first optical waveguide region and has a heater for changing a refractive index of the second optical waveguide region. The metal pattern is provided on an area to be thermally coupled to a temperature control device. The thermal conductive material couples the metal pattern with an upper face of the first optical waveguide region of the optical semiconductor element. The thermal conductive material is electrically separated from the first optical waveguide region.

Abstract: Light emitted from a wide stripe semiconductor laser with increased output and efficiency is passed through a mode converter and a wavelength selecting filter, then fed back to the active layer of the semiconductor laser, which fixes the oscillation mode of the semiconductor laser to single mode, making lateral-mode control possible.

Abstract: The present invention provides an improved mesa vertical-cavity surface-emitting laser (VCSEL), in which a first distributed Bragg reflector (DBR) mesa of semiconductor material is disposed on a top surface of an active layer. A contact annulus is disposed on a contact region of a top surface of the first DBR mesa, such that an inner circumference of the contact annulus defines a window region of the top surface of the first DBR mesa. A second DBR mesa of dielectric material is disposed on the window region. Whereas the first DBR mesa has a first reflectance at a lasing wavelength that is insufficient to sustain lasing in the active layer, the first DBR mesa and the second DBR mesa together have a total reflectance at the lasing wavelength that is sufficient to sustain lasing in the active layer under the window region.

Abstract: The present invention is to provide a semiconductor laser with a feedback grating comprised of InP and AlGaInAs without InAsP put therebetween, and to provide a method for manufacturing the DFB-LD having such grating. The LD includes an n-type InP substrate, an AlInAsP intermediate layer, an AlGaInAs lower SCH layer, an active layer, and a p-type layer for upper cladding in this order from the InP substrate. The InP substrate, the AlInAsP intermediate layer, and the AlGaInAs lower SCH layer constitute the feedback grating. The AlInAsP intermediate layer lowers a series resistance along these semiconductor stacks.

Abstract: A semiconductor optical amplifier according to the present invention comprises a lower cladding layer of a first conductive type, an upper cladding layer of a second conductive type, an active layer, and a diffraction grating layer. The lower cladding layer includes first and second regions. The first and second regions are arranged in a predetermined direction, and the upper cladding layer is supported by the first region. The active layer is provided between the first region of the lower cladding layer and the upper cladding layer, and the diffraction grating layer has a diffraction grating. The diffraction grating extends in the predetermined direction. The diffraction grating layer is supported by the second region, and the diffraction grating layer is optically coupled to the active layer.

Abstract: Arrayed DBR (Distributed Bragg Reflector) laser shows a problem that spectrum purity is deteriorated when a current is flowed in a semiconductor optical amplifier for attaining a sufficient optical output. In addition, the arrayed waveguide grating laser shows a problem that the spectrum purity is deteriorated by leakage of light. An output end of each of the laser channels is provided with a gate (a core) that can be controlled through bias application. The gate has a function for amplifying light when the laser channels are operated and for absorbing light when the laser channels are not operated.

Abstract: A MEMS-tunable semiconductor optical amplifier (SOA). A device in accordance with the present invention comprises a substrate, a first mirror, coupled to the substrate, a second mirror, an active region, coupled between the first and second mirror, and a microelectromechanical actuator, coupled to the second mirror, wherein a voltage is applied to the microelectromechanical actuator to tune the SOA.

Abstract: A semiconductor laser is formed on a semiconductor substrate with an array of laterally spaced laser device elements each including a second order distributed feedback grating bounded by distributed Bragg reflector gratings. The device elements in which the distributed feedback grating and the distributed Bragg reflector gratings are formed have a lower effective index than the index of the interelement regions and are spaced so as to form an antiguided array.

Abstract: In a surface emitting semiconductor laser, a first distributed Bragg reflector includes first and second semiconductor layers of a first conductive type, and the first and second semiconductor layers are alternately arranged. A second distributed Bragg reflector includes first and second portions, and the first and second portions are arranged in a direction of a predetermined axis. The first portion is made of semiconductor, and the second portion is made of dielectric. An active layer is provided on the first distributed Bragg reflector, and the first portion of the second distributed Bragg reflector is provided between the active layer and the second portion of the second distributed Bragg reflector. The first distributed Bragg reflector, the active layer and the second distributed Bragg reflector are sequentially arranged in the direction of the predetermined axis.

Abstract: A VCSEL includes a first distributed Bragg reflector (DBR) of a first conductivity type formed on a substrate and including at least one semiconductor layer to be oxidized, an active region having a column shaped structure and formed on the first DBR, and a second DBR of a second conductivity type. At least one hole starting from a surface of the first DBR and reaching the at least one semiconductor layer to be oxidized is formed in the first DBR outside of a column shaped structure of the second DBR. An oxidized region is formed in the semiconductor layer to be oxidized by selectively oxidizing from a side surface of the hole. In the first DBR, a first current path is formed by a conductive region surrounded by the oxidized region, and a second current path is formed by a conductive region not surrounded by the oxidized region.

Abstract: Apparatus, methods, systems and devices for providing a temperature independent laser by determining a temperature dependence of a lasing wavelength, selecting the lasing wavelength having minimal temperature dependence and constraining the lasing wavelength of the laser device to the selected lasing wavelength. In an embodiment, a volumetric Bragg grating in photo-thermal refractive glass is used as a laser cavity mirror for constraining the laser emission at the selected wavelength. The laser device may be a broad spectrum laser such as an Er3+ doped glass broad spectrum laser. In an embodiment, the lasers are operated where the temperature dependence of the stimulated emission cross section is used to compensate for temperature dependent changes of other laser components.

Abstract: Laser diodes are formed with an outcoupling grating between two separate distributed Bragg reflectors. The devices have gain regions located between the reflector gratings for pumping the active region. The outcoupling grating couples light out of the waveguide normal to the surface if the grating spacings are equal to an integer number of wavelengths of the light within the cavity. If the gratings are not such an integer number, the light is coupled out of the cavity off the normal.

Abstract: An integrated light emitting semiconductor device having integrated feedback for wavelength locking comprises a semiconductor substrate including a waveguide region having a gain section having a gain media therein, and an out-coupling perturbation integrated with the device disposed proximate to the waveguide. A total internal reflection (TIR) structure for providing optical feedback is integrated with the device and disposed in a spaced apart relation relative to the out-coupling perturbation. At least one of the out-coupling perturbation and the TIR structure include a grating or prism to provide dispersion to send different wavelengths of light in different directions. The out-coupling perturbation is preferably a grating that has a grating period that is small enough to allow for only the +1 diffracted order to propagate.

Abstract: A method and apparatus for modifying the out of band reflection of a laser element is described. The laser element includes an active medium excited by optical pumping means to produce stimulation emission of light. The laser element further includes a Bragg grating structure for providing optical feedback for the active medium, with the Bragg grating structure including a phase transition region providing a change in phase. The change in phase of the phase transition region is adjusted to modify out of band reflection of said laser element.

Abstract: A surface-emitting type semiconductor laser includes: an upper mirror and a lower mirror each composed of alternately formed first semiconductor layers and second semiconductor layers; an active layer disposed between the upper mirror and the lower mirror, wherein the surface-emitting laser emits laser light in a direction in which the first semiconductor layers and the second semiconductor layers are formed; a thick film layer formed with one of the first semiconductor layers composing the lower mirror, the thick film layer being thicker than other of the first semiconductor layers; and a third semiconductor layer provided between the thick film layer and one of the second semiconductor layers on the thick film layer, the third semiconductor layer having a refractive index between a refractive index of the first conductive layer and a refractive index of the second semiconductor layer.

Abstract: An optical structure enabling properties of the surface plasmons to be used is defined from a substantially binary, parameterizable unit pattern ME. The parameters a, b, c, d and hg of the pattern are chosen so as to maximize the complex amplitudes of the first two harmonics of the complex Fourier series describing the pattern ME. This structure is advantageously used in combination with a photodetector, an infrared or Terahertz optical wave emitter, or a field emission device.

Abstract: A light source includes a semiconductor laser diode and a narrow spectral and spatial bandwidth reflector in optical communication with respect to the semiconductor diode laser and aligned with the output beam of the diode laser, such that a portion of the light in the output beam is reflected back into the laser.

Abstract: A surface emitting semiconductor laser comprises first and second distributed Bragg reflectors, an active layer and a junction region. The first distributed Bragg reflector includes first III-V compound semiconductor layers and second III-V compound semiconductor layers, and the first and second III-V compound semiconductor layers are alternately arranged. The second distributed Bragg reflector includes a first portion and a second portion. The first portion including third III-V compound semiconductor layers and fourth III-V compound semiconductor layers, and the third and fourth III-V compound semiconductor layers are alternately arranged. The second portion includes first insulating layers and second insulating layers, and the first and second insulating layers are alternately arranged. The active layer is provided between the first distributed Bragg reflector and the second distributed Bragg reflector. The active layer is made of III-V compound semiconductor.

Abstract: The present invention is directed to a method and system for providing phase modulated current to a semiconductor laser to control beam wavelength. A first current is received into a gain portion of the semiconductor laser and a second current is received into a DBR portion of the semiconductor laser. The second current is phase modulated based upon a required intensity value. An output beam is generated by the semiconductor laser based upon the received first current and the received second current.

Abstract: A vertical cavity surface emitting laser system is provided including providing a epitaxially grown bottom spacer layer, an active layer on the epitaxially grown bottom spacer layer, a top spacer layer on the active layer, and etching a part of the epitaxially grown top spacer layer on a side opposite the active layer.

Abstract: The invention provides an optoelectronic device combining a vertical cavity surface emitting laser (VCSEL) and a photodetector for monitoring the output power of the vertical cavity surface emitting laser. To improve the signal-to-noise ratio of the photodetector, a light deflector is interposed between the photodetector and the VCSEL.

Abstract: A vertical-cavity surface emitting laser includes a substrate and a first mirror that is grown on the substrate, a second mirror grown on the first mirror for resonating the first mirror and light, an active layer between the first mirror and the second mirror for generating and amplifying the light, an upper electrode grown on the active layer and a lower electrode formed on the first mirror for supplying current to the active layer, a planarizing polymer formed on the first mirror for burying the active layer and the second layer, and a first external terminal extending from the upper electrode in a vertical upward direction to be exposed to the top surface of the planarizing polymer and a second external terminal extending from the lower electrode to expose its one surface to the top surface of the planarizing polymer.

Abstract: In a semiconductor optical device, the first conductive type semiconductor region includes a first semiconductor portion and a second semiconductor portion. The first and second regions of the first semiconductor portion are arranged along a predetermined plane. The second semiconductor portion is provided on the first region of the first semiconductor portion. The active layer is provided on the second semiconductor portion of the first conductive type semiconductor region. The second conductive type semiconductor region is provided on the second region of the first semiconductor portion of the first conductive type semiconductor region. The side of the second semiconductor portion of the first conductive type semiconductor region, the top and side of the active layer, the second region of the first conductive type semiconductor region and the second conductive type semiconductor region constitute a pn junction.

Abstract: A surface emitting laser includes a substrate, a first Bragg reflector layer formed on the substrate, an active layer formed on the first Bragg reflector layer and having a light-emitting region, a second Bragg reflector layer formed on the active layer to emit light from the surface in the direction of the optical axis (Z), and a light-scattering member for extracting light from the surface of the second Bragg reflector layer in a direction intersecting the optical axis. With this arrangement, the intensity of light emitted from the surface emitting laser in one direction can be monitored by a simple structure.

Abstract: A surface-emitting type semiconductor laser includes: a lower mirror; an active layer formed above the lower mirror; and an upper mirror formed above the active layer, wherein each of the lower mirror and the upper mirror is composed of a multilayer mirror in which a plurality of unit multilayer films are laminated, each of the unit multilayer films includes a pair of a lower refractive index layer and a higher refractive index layer laminated in a thickness direction, each of the unit multilayer films satisfies a formula (1) below, and the active layer satisfies a formula (2) below, dD<?/2nD??(1) dA>m?/2nA??(2) where ? is a design wavelength of the surface-emitting type semiconductor laser, m is a positive integer, dD is a thickness of the unit multilayer film, nD is a mean refractive index of the unit multilayer film, dA is a thickness of the active layer, and nA is a mean refractive index of the active layer.

Abstract: A method of manufacturing a tuneable laser assembly including a substrate having formed thereon a plurality of tuneable lasers including Multi Quantum Well (MQW) active sections as well as distributed Bragg reflector (DBR) tuning sections. The lasers have respective emission wavelengths and tuning ranges such that the laser assembly can be tuned over a quasi-continuous predetermined wavelength range. The assembly also includes a plurality of passive waveguides coupled to the lasers to receive therefrom the respective emission wavelengths as well as an optical coupler coupled to the waveguides to receive via the waveguides the emissions wavelengths from the lasers. A Multi Quantum Well (MQW) amplifier coupled to the coupler amplifies the emission wavelengths coupled via the optical coupler.

Abstract: A surface-emission laser diode comprises a cavity region over a semiconductor substrate and includes an active layer containing at least one quantum well active layer producing a laser light and a barrier layer, a spacer layer is provided in the vicinity of the active layer and formed of at least one material, an upper and lower reflectors are provided at a top part and a bottom part of the cavity region, the cavity region and the upper and lower reflectors form a mesa structure over the semiconductor substrate, the upper and lower reflectors being formed of a semiconductor distributed Bragg reflector having a periodic change of refractive index and reflecting incident light by interference of optical waves, at least a part of the semiconductor distributed Bragg reflector is formed of a layer of small refractive index of AlxGa1-xAs (0<x?1) and a layer of large refractive index of AlyGa1-yAs (0?y<x?1), the lower reflector is formed of a first lower reflector having a low-refractive index layer of AlAs an

Abstract: In general, a complex-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 complex-coupled DFB laser may be configured with a wavelength monitoring section and may be configured to provide facet power asymmetry. The wavelength monitoring section may include a second-order grating section configured to emit radiation (e.g., vertical radiation) from a side of the DFB laser for monitoring.