Abstract: Disclosed is a method for maintaining wavelength-locking of a Fabry-Perot laser regardless of a change of external temperature even though a temperature controller is not used, and a wavelength division multiplexing (WDM) light source using the method, as an economical light source used in a WDM optical communication field. The WDM light source comprises a Fabry-Perot laser for injecting spectrum-spliced incoherent light to amplify and output only an oscillation mode matching with a wavelength of the injected light, and a bias controlling unit for adjusting a bias current supplied to the Fabry-Perot laser to a value adjacent to a threshold current of the Fabry-Perot laser, whose threshold current is changed according to a temperature and a relationship between the injected light changed depending to a temperature and a wavelength of the oscillation mode.

Abstract: Provided is a semiconductor laser diode. The semiconductor laser diode includes a first material layer, an active layer, and a second material layer, characterized in that the semiconductor laser diode includes: a ridge waveguide, which is formed in a ridge shape over the second material layer to define a channel defined so that a top material layer of the second material layer is limitedly exposed, and in which a second electrode layer which is in contact with the top material layer of the second material layer via the channel is formed; and a first protrusion, which is positioned at one side of the ridge waveguide and has not less height than that of the ridge waveguide.

Abstract: An improved tunnel junction structure and a VCSEL that uses this structure is disclosed. The tunnel junction includes first, second, and third layers that include materials of the InP family of materials. The first layer is doped with n-type dopant species to a concentration of 1019 dopant atoms per cm3 or greater. The second layer is doped with Zn to a similar concentration and is in contact with the first layer. The interface between the first and second layers forms a tunnel junction. The third layer includes a material that retards the diffusion of Zn out of the second layer. The third layer preferably includes undoped AlInAs. The tunnel junction structure of the present invention can be utilized in a VCSEL having an active layer between first and second mirrors that are both constructed from n-type semiconductor layers.

Abstract: A laser diode module with a built-in high-frequency modulation IC used to remove the reflected noise generated as the laser beam reads the signal to be played back and directly packaged within a metal cap. The high-frequency modulation IC creates an electrical connection through wire bonding with several connection legs and the laser diode module. The packaged laser diode module has four connection legs. Two of these connection legs act as a positive and a negative terminal for supplying power to the built-in high-frequency modulation IC. The other two connection legs are electrically connected to an external automatic power control (APC) circuit and act as the positive terminal of the laser diode and the photo diode, respectively. In this way, the inconvenience of externally attaching a high-frequency current producing circuit board can be avoided, the productivity can be enhanced and the radiation of electromagnetic interference (EMI) can be reduced.

Abstract: A glass fiber (22) has a core (24) provided with Raman laser effect particles (28) embedded in a glass matrix (30), with glass cladding (26) around the core. The refractive index of the glass matrix (30) is matched to that of the Raman laser effect particles (28) so as to avoid scattering. It is not necessary to have a single crystal of Raman laser material to create a laser effect in the glass fiber. A length of fiber in the order of meters or tens of meters can produce optical laser light. It is possible to have a single fiber (22) emit laser light at different frequencies due to Stokes and Anti-Stokes emissions. A simple laser device can therefore produce several colors of laser beams.

Abstract: An electrically controlled variable reflectance mirror that includes a Pockels cell which enables its retardation or birefringence to be controlled in order to vary the light outcoupled from a laser cavity. Since the retardation is a function of the voltage applied to the Pockels cell, the voltage can be used to control the fraction of the output beam that is outcoupled from the laser cavity. The Pockels cell is formed with a constant reflectivity profile to form an electrically controlled uniform reflectivity electro-optic mirror. In an alternate embodiment of the invention, the Pockels cell is configured with spatially varying retardation to form an electrically controlled graded reflectivity electro-optic mirror. Both embodiments of the invention enable a lasing system, such as a solid state lasing system, to be operated over a relatively wide range of operating parameters utilizing a single set of optics.

Abstract: An optical fiber laser has an output that is stabilized to adapt to changes in laser operating temperature. At the output of the laser a plurality of wavelength-selective stabilizing reflectors is provided, each having a reflectivity profile with a different center wavelength. The reflectors, typically Bragg gratings, have a relative degree of reflectivity and relative wavelength separation that results in the output power of the laser being at one or more of the reflector center wavelengths throughout the temperature change. Thus, as a temperature shift causes the wavelength of the optical energy generated in the laser gain medium to change, the grating-stabilized output of the laser shifts between one locked wavelength and another. However, the output remains stable over the extended wavelength range provided by the multiple reflectors. Such a laser is particularly useful in an amplifier system in which the laser is used as an optical pump source.

Abstract: An optical fiber laser includes a resonator comprising an erbium-doped glass fiber serving as a gain medium and a pumping light source that launches pumping light into the erbium-doped glass fiber. The pumping light source emits pumping light of a wavelength of 980 nm or longer, and the optical fiber laser emits laser light in a wavelength band of 2.8 ?m (2.7 ?m to 3.0 ?m).

Abstract: Apparatus/method providing bandwidth control in narrow band short pulse duration gas discharge laser output light pulse beam producing systems, producing a beam comprising pulses at selected pulse repetition races, e.g., comprising a dispersive bandwidth selection optic selecting at least one center wavelength for each pulse determined at least in part by the angle of incidence of the beam containing the respective pulse on the optic; a tuning mechanism operative to select at least one angle of incidence of the beam containing the respective pulse upon the optic; the tuning mechanism comprising a plurality of incidence angle selection elements each defining an angle of incidence for a different spatially separated but not temporally separated portion of the pulse to return from the optic a laser light pulse comprising a plurality of spatially separated but not temporally separated portions, each having one of at least two different selected center wavelengths.

Abstract: Optoelectronic devices, such as optical transmitters and optical amplifiers, are provided. The optoelectronic devices are suitable for use in connection with optical communications systems, and related components and devices, such as may be used in the transmission, reception and processing of data and other information. The optoelectronic devices are implemented as various types of semiconductors. The form, structure, properties and functionality of a particular optoelectronic semiconductor device are determined with reference to the application(s) in connection with which the optoelectronic device is to be employed.

Abstract: A laser oscillation apparatus includes a wavelength change unit for driving a wavelength selection element in a band-narrowing module and changing the oscillation wavelength of a laser beam to a target value, and an oscillation history memory for storing the oscillation state of the laser beam as an oscillation history. The wavelength change unit drives the wavelength selection element on the basis of the oscillation history and changes the oscillation wavelength of the laser beam to the target value.

Abstract: A semiconductor laser includes an active layer formed on a substrate and a pair of cladding layers sandwiching the active layer. On at least one of resonator end faces of the semiconductor laser, a first dielectric film with hydrogen added therein is provided. Between the first dielectric film and the resonator end face, a second dielectric film for suppressing the diffusion of hydrogen is provided. Even when a semiconductor laser with an end face coating film including a hydrogen-added film is exposed to high temperatures, peeling of the end face coating film and deterioration of the end face coating film can be suppressed.

Abstract: A semiconductor optical device 100 has an n-type semiconductor layer 2, an active layer 3, and a p-type semiconductor portion 4 provided in order on a principal surface 1a of a substrate 1. The p-type semiconductor portion 4 has a ridge portion 40 and a base portion 42, and a contact layer 5 is formed on the ridge portion 40. A first portion 60 of an insulating layer 6 extends along a plane intersecting with the principal surface 1a of the substrate 1, on a side face 4b of the ridge portion 40 and on a side face 5b of the contact layer 5. An end 6a of the first portion 60 is higher than an edge 5c of the side face 5b of the contact layer 5.

Abstract: A chip carrier having improver thermal properties, wherein the chip carrier may be formed having waist section, and a first transverse end portion joined to the waist section. A first surface of the carrier being configured to receive a chip thereon, and a second surface of the carrier configured to be coupled to a thermal control unit to provide cooling of the carrier and chip. The chip carrier may have a second transverse end portion joined to the waist portion in certain embodiments.

Abstract: A laser diode driving circuit includes two chip capacitors disposed in the vicinity of one side portion of an IC along which a high voltage power supply terminal, a low voltage power supply terminal and a driving signal output terminal are disposed. One end portion of each of the chip capacitors is connected to the high voltage power supply terminal and the other end portion of each of the chip capacitors is connected to the low voltage power supply terminal. The chip capacitors are adapted for serving to reduce a ripple component superposed on a power supply voltage when a switching element is operated. The chip capacitors are disposed so that the distance between itself and the high voltage power supply terminal, the low voltage power supply terminal and the driving signal output terminal is equal to or shorter than 10 mm.

Abstract: A semiconductor laser device includes a semiconductor substrate on which a semiconductor thin film including an active layer is lamineted, a pair of electrodes respectively provided on opposite faces of the substrate, a light emitting surface defined on a side face of the substrate to which the active layer and an edge of at least one of the electrodes are exposed, and a protective film covering the light emitting surface. The protective film has a smaller thickness on the edge of the electrode than on the active layer. This arrangement makes it possible to suppress diffusion of an electrode material in the protective film and sufficiently protect the light emitting surface.

Abstract: A semiconductor laser device has a semiconductor laser and a polarizing diffraction grating that is arranged ahead of the semiconductor laser. A reflected light from an optical recording medium is diffracted by the polarizing diffraction grating according to the polarization direction of the reflected light. The reflected light is thereby deviated from the direction toward the semiconductor laser to prevent the reflected light from returning to the semiconductor laser.

Abstract: To provide a semiconductor laser device which has no ripple and can afford better FFP having a pattern near a Gaussian distribution upon operation at the high output, the semiconductor laser comprising a laminate structure in which a first conductive type semiconductor layer, an active layer and a second conductive type semiconductor layer different from the first conductive type are laminated in this order, the laminate structure having a waveguide region to guide a light and resonator planes for laser oscillation on both ends, characterized in that the laminate structure has a non-resonator plane on one end side and the non-resonator plane is covered with a shading layer.

Abstract: A circuit for generating a clock or sampling signal, the circuit including: a semiconductor quantum dot laser element including a region of quantum dots, wherein the region of quantum dots is characterized by an emission distribution having a half-width of at least about 10 meV; and drive circuitry connected to the quantum dot laser element for operating the quantum dot laser element as a mode-locked laser that outputs a periodic, uniformly spaced sequence of pulses, wherein the clock or sampling signal is derived from the sequence of pulses.

Abstract: An object of the present invention is obtaining a semiconductor film with uniform characteristics by improving irradiation variations of the semiconductor film. The irradiation variations are generated due to scanning while irradiating with a linear laser beam of the pulse emission. At a laser crystallization step of irradiating a semiconductor film with a laser light, a continuous light emission excimer laser emission device is used as a laser light source. For example, in a method of fabricating an active matrix type liquid crystal display device, a continuous light emission excimer laser beam is irradiated to a semiconductor film, which is processed to be a linear shape, while scanning in a vertical direction to the linear direction. Therefore, more uniform crystallization can be performed because irradiation marks can be avoided by a conventional pulse laser.