Abstract: A semiconductor laser device has on a compound semiconductor substrate at least a lower cladding layer, an active layer, an upper cladding layer and a contact layer. An upper part of the upper cladding layer and the contact layer are formed as a mesa-structured portion having a ridge stripe pattern, and the both sides of the mesa structured portion are buried with a current blocking layer. The laser device includes the current blocking layer having a pit-like recess penetrating thereof and extending towards the compound semiconductor substrate, and a portion of the recess other than that penetrating the current blocking layer being covered or buried with an insulating film or a compound semiconductor layer with a high resistivity. The compound semiconductor substrate and the electrode layer thus can be kept insulated in an area other than a current injection area, thereby non-emissive failure due to short-circuit is prevented.

Abstract: An optical device has a back facet (27) and a front facet (29; 29?) opposite to each other, and includes a laser (23) adapted to emit light essentially perpendicular to said back facet; a modulator (25; 51; 55) having an input end and an output end (35; 53; 57), respectively, and adapted to receive and modulate light emitted from said laser and to output modulated light at said modulator output end; and a window region (33) arranged between said modulator output end and said device front facet, said device being further arranged such that modulated light output from said modulator is transmitted through said window region and is output from said device through said device front facet. The modulator is bent such that the modulated light output from said modulator is propagating essentially in a direction (34), which is angled (?; ?) with respect to the normal (Z; 71) of said device front facet.

Abstract: A distributed feedback laser device inhibiting beam coupling coefficient variation resulting from fabrication dispersion and improving fabrication yield. The distributed feedback laser device includes cladding layers provided on an InP substrate and located on both sides of an active layer and a diffraction grating having grating bars, different in refractive index from the cladding layers, in either cladding layer and extending in a direction perpendicular to a light emission direction at a prescribed pitch in the emission direction, as well as at least one light distribution control layer, located in the cladding layer, spaced from the diffraction grating and having the same composition as the diffraction grating.

Abstract: A method and circuit for measuring the optical modulation amplitude in the operating region of a laser diode is described. The method utilises two measurements of OMA, each measurement being related to the slope in a specific portion of the operating region of the power/current characteristic curve of the laser diode. By combining the two measurement values, the invention provides a 1 measurement for OMA in the operating region of the laser diode that allows for the presence of a non-linear response in the region.

Abstract: A laser unit has a laser mode selection and provides a laser signal in accordance to a laser control parameter. A plurality of pairs of values is determined for the laser control parameter and a laser operation parameter indicative of the laser unit's operation to provide the laser signal. A target operating point for the laser unit is derived from the determined pairs of values in conjunction with a model and a selection criterion for selecting the target operating point, wherein the model represents an assumed relationship between the laser control parameter and the laser operation parameter. A curve for the relationship between the laser control parameter and the laser operation parameter is approximated based on the determined pairs of values in conjunction with the model, the curve limited on at least one side having a defined boundary in a range where mode hopping is likely, and the target operating point selected on the approximated curve based on the selection criterion.

Abstract: An apparatus and method for monitoring the optical output of vertical cavity surface emitting lasers (VCSELS) utilizes a portion of light emitted by the VCSEL and scatters and/or reflects this portion of emitted light so that it is directed towards a detecting surface of a photodetector. In one embodiment, scattering elements may be incorporated within the epoxy or other coupling medium used to couple the VCSEL to the optical fiber. In another embodiment, the VCSEL may be coupled to an optical fiber secured within a ferrule which has an end surface capable of reflecting or scattering light and directing the light towards the photodetector. In another embodiment, a reflective integrating member may be alternatively or additionally used to reflect a portion of the emitted light to the photodetector. The photodetector, in conjunction with electrical circuitry to which it is coupled, develops an electrical signal which may be provided to laser control means to control and adjust the optical output of the VCSELs.

Abstract: Selectively oxidized vertical cavity lasers emitting at about 1290 nm using InGaAsN quantum wells that operate continuous wave below, at and above room temperature are reported. The lasers employ a semi-insulating GaAs substrate for reduced capacitance, high quality, low resistivity AlGaAs DBR mirror structures, and a strained active region based on InGaAsN. In addition, the design of the VCSEL reduces free carrier absorption of 1.3 ?m light in the p-type materials by placing relatively higher p-type dopant concentrations near standing wave nulls.

Abstract: The invention relates to a laser amplifier system consisting of a solid body, which comprises a laser-active medium, of a pumping radiation source for generating a pumping radiation field, which repeatedly permeates the solid body, and of a focusing system. Said focusing system generates a number of different branches of the pumping radiation field that enter the solid body and converts at least one branch emerging from the solid body into one of the branches which enter the solid body and which are different from the emerging branch. The aim of the invention is to improve a laser amplifier system of the aforementioned type in order to be able to generate the highest possible pumping power density in the solid body while requiring the smallest possible amount of complexity.

Abstract: An object of the present invention is to remove a laser beam source noise in an optical disc device. An optical disc device comprises: a laser beam source which outputs a laser beam, a reproducing signal beam-receiver which receives a signal beam from an optical disc and generates a reproducing signal, a beam-source monitoring beam-receiver which detects the laser beam from the laser beam source, and a beam splitter which divides the laser beam from the laser beam source into the beams to the reproducing signal beam-receiver and to the beam-source monitoring beam-receiver; an output signal from the beam-source monitoring beam-receiver being used for removing a noise contained in the reproducing signal from the reproducing signal beam-receiver through a noise cancellation calculation.

Abstract: According to the present invention, an optical transmitting system, which enables a precise control of the power and the extinction ratio of the optical output without a small amount of the preset data, will be provided. The system comprises a laser module and a control system that supplies a bias current and a modulation current to the laser module. In the present invention, one of the bias current and the modulation current of the semiconductor laser in the laser module is varied to maintain the power and the extinction ratio of the optical output, and the other of the bias current and the modulation current is calculated based on the specific function. Only coefficients of the specific function are stored in the control system. Therefore, the present invention does not need a large size of the storage in which both the bias current and the modulation current are stored as a table.

Abstract: At least a lower cladding layer, an active layer for generating laser light, a first upper cladding layer, an etching stopper layer and a second upper cladding layer are stacked on a substrate. An impurity for restraining laser light absorption is diffused into the second upper cladding layer along a region where a light-emitting end surface is to be formed, under a condition that allows the etching stopper layer to maintain a function of stopping etching for the second upper cladding layer (First annealing process). Etching is performed until the etching stopper layer is reached such that the second upper cladding layer is left in a ridge shape. The impurity in the second upper cladding layer is re-diffused into the active layer to thereby cause local intermixing of the active layer in a portion extending along the light-emitting end surface and located just under the ridge (Second annealing process).

Abstract: A laser diode capable of reducing a radiating angle ?? in the vertical direction, an optical pickup device, an optical disk apparatus, and optical communications equipment, all equipped with the laser diode which increases optical coupling efficiency. It has a first cladding layer of the first conductive type formed on a substrate, with an active layer on top of the first cladding layer and a second cladding layer of the second conductive type on top of the active layer. In at least the first or second cladding layer, it is formed of at least one optical guide layer having a higher refractive index than the first or second cladding layer and operating to expand a beam waist in the waveguide. This operation contributes to widening a region in which to shut up light, enabling a radiating angle ?? in the vertical direction to be reduced.

Abstract: The present invention relates to a two stage laser system in which a desired spectral line width can be obtained at high output even when the integrated spectral characteristic of oscillator laser does not have the desired spectral line width, comprising an oscillator laser device 10 which has discharge electrodes 2 within a laser chamber 1 filled with laser gas containing F2 and emits laser beam which is band-narrowed by means of a band narrowing module 3 arranged in a laser resonator, and an amplifier laser device 20 which has discharge electrodes 2 within a laser chamber 1 filled with laser gas containing F2 and amplifies laser pulse injected from said oscillator laser device 10. In the system, a synchronous time interval having a predetermined spectral line width exists in laser pulse from the oscillator laser 10, and the system is set such that a discharge occurs in the amplifier laser 20 within the synchronous time interval.

Abstract: A temperature insensitive vertical cavity laser includes an active region, having a plurality of quantum wells, formed between first and second mirrors. The gain of each of said quantum wells or groups of quantum wells operate quasi-independently at different temperatures such that stimulated emission is dominated by a different quantum well or group of quantum wells at different temperatures.

Abstract: In embodiments, the present invention is directed to systems and methods for operating an incoherently beam combined (IBC) laser. The IBC laser may comprise an integrated set of emitters or a set of discrete emitters. Each emitter is associated with a high-pass, low-pass, or bandpass optical filter. The emitters and filters are disposed in an ordered arrangement thereby defining a common optical path. Near the end of the common optical path, a focusing lens may be utilized to focus the output beams from each of the emitters into a fiber. A partially reflective component may be embedded in the fiber to provide feedback to each of the emitters. By selecting the optical characteristics of the filters, light originating from a specific emitter is fed back to the same emitter and to no other emitter. Accordingly, multiple external laser cavities are created on the same optical path.

Abstract: A laser diode collimating system comprises a collimating lens for receiving a laser beam from a laser diode LD. First and second orthogonally arranged cylindrical lenses are provided through which the laser beam passes. The cylindrical lenses are positioned so as to have a substantially common focal plane and operate substantially independently on the divergence and/or convergence of the laser beam in its fast axis and slow axis directions respectively. A convex lens, through which the beam passes, has a focus lying in the said common focal plane.

Abstract: Disclosed is a laser having a laser diode coupled with a passive intra-cavity tapered waveguide.

Abstract: An organic vertical cavity laser device includes a substrate; a bottom dielectric stack reflective to light over a predetermined range of wavelengths and being disposed over the substrate, and an organic active region for producing laser light. The device also includes a top dielectric stack spaced from the bottom dielectric stack and reflective to light over a predetermined range of wavelengths, and a thermally conductive transparent layer disposed between the bottom dielectric stack and the organic active region or between the top dielectric stack and the organic active region or both.

Abstract: A semiconductor laser apparatus comprises a semiconductor laser chip disposed on a base through an electrode area, wherein the electrode area comprises at least a first electrode layer having no opening and a second electrode layer having an opening from the semiconductor laser chip side, the second electrode layer is formed of materials different from those of the first electrode layer and the opening of the second electrode layer is shaped in such a manner as to allow observation of a light emitting portion of the semiconductor laser chip by etching the first electrode layer using the second electrode layer as a mask. Another semiconductor laser apparatus comprises first and second electrode areas on the upper surface and the lower surface of the semiconductor laser chip, wherein both the first and the second electrode areas comprise at least the first electrode layer having no opening and the second electrode layer having the opening from the semiconductor laser chip side.

Abstract: A system for tuning one or more second radiant sources relative to a first radiant source may include a coupler configured to combine output signals from the first radiant source and a second radiant source to generate a heterodyne signal containing a frequency difference between the output signals from the first radiant source and the second radiant source. A photodetector may be configured to convert the heterodyne signal into an electrical signal containing the frequency difference. A spectrum analyzer may be configured to measure the frequency difference in the electrical signal and generate a precise difference value. A controller may be configured to adjust a wavelength of the second radiant source relative to that of the first radiant source based on the precise difference value. Laser spectroscopy may be performed by passing the output signals from the first radiant source and the second radiant source through a sample volume and detecting reflected or emitted radiation.