Abstract: An optical filter uses a multi-layer, stack of alternating dielectric layers (16, 18) of different refractive indices, a dielectric spacer layer (20) and metal layer (21), to achieve a narrow overall absorption bandwidth, with high reflectance upon either side. A tunable (optical) filter variant uses a dielectric stack and spacer coating of spatially-varying thickness, that is a coating of depth varying, say linearly and/or circularly, according to position across an absorbent layer or substrate, whereby, at different positions on the surface, a different wavelength is absorbed. A tunable laser (35) uses opposed tunable filters (26, 28) bounding a lasing medium (38), such as CO2 gas, for selective variable stimulated emission of radiation (39).

Abstract: Apparatus and methods that utilize tunable elements to provide for selective wavelength tuning of a light beam. The apparatus comprises a first tunable wavelength selection element having a first adjustable free spectral range, a second tunable wavelength selection element having a second adjustable free spectral range, with the first and second tunable wavelength selection elements configured to define a tunable joint transmission peak. The first and second tunable wavelength selection elements respectively define first and second pluralities of tunable transmission peaks, wherein respective ones of each of the first and second plurality of transmission peaks are aligned to obtain a joint transmission peak that may be adjusted by tuning the wavelength selection elements. The free spectral ranges of the wavelength selection elements are configured to enable a Vernier tuning effect.

Abstract: An n-side electrode, an n-substrate, an n-buffer layer, a GRIN-SCH-MQW active layer, a p-spacer, a p-cladding layer, a p-contact layer, and a p-side electrode are laminated one on top another in that order. Above the n-buffer layer, the GRIN-SCH-MQW layer and the p-spacer layer occupy a narrower area than the n-substrate in a direction that is at right angles to the laser emission direction, wherein the remaining area is occupied by a p-blocking layer and an n-blocking layer. Within the p-spacer layer are embedded a first diffraction grating and a second diffraction grating. Between the first and the second diffraction grating and the p-side electrode is provided a current non-injection area.

Abstract: Techniques and designs for tunable and dynamically stabilized a laser wavelength in various lasers, including fiber lasers and actively mode-locked lasers. In an actively mode-locked laser, a dynamic wavelength tuning control and a dynamic cavity length control are implemented to maintain mode locking during tuning of the laser wavelength.

Abstract: A laser apparatus, which generates laser light to be transmitted through an optical transmission system includes a laser that emits light that is substantially linearly polarized, a housing in which the laser is mounted, and a quarter wave retarder plate. The quarter wave retarder plate is disposed so that the emitted laser light passes through the quarter wave retarder plate prior to transmission of the emitted laser light through the optical transmission system. The quarter wave retarder plate causing the emitted laser light to become circularly polarized with a predefined handedness. The quarter wave retarder plate is also disposed so that light reflected by the optical transmission system back toward the laser passes through the quarter wave retarder plate a second time prior to reaching the laser, causing the reflected light to become linearly polarized with a linear polarization that is orthogonal to the polarization state of the light emitted by the laser.

Abstract: A semiconductor laser device includes a substrate having on a surface thereof a semiconductor diode laser portion and a linear amplifier portion. Each of the laser portion and amplifier portion has a waveguide layer with the waveguide layers being in alignment. The laser portion is of a structure which permits it to generate radiation and emit the radiation from one end. The amplifier has an end that receives the radiation from the laser portion, and another end with emits the radiation after the radiation is amplified. The device emits FM radiation but not IM radiation.

Abstract: A double cladding fiber includes an inner core doped with active species, an inner cladding disposed adjacent said inner core for receiving pumping energy, minimizing local modes in said inner cladding, and transferring said pumping energy to the core. An outer cladding is disposed adjacent the inner cladding. The cross section of said inner cladding has a polygon-like shape with its boundary being a plurality of well-defined arcs, each of the arcs having substantially different arc center for delivering energy with maximum efficiency to the inner core meeting the limitation of: (1−L/r1)(1−L/r2)<0, or (1−L/r1)(1−L/r2)>1; where r1 and r2 is the arc radius of the inner cladding surfaces that are opposite to each other (mirror pair), with the radius of a concave mirror being positive and that of a convex mirror being negative, L is the distance between two mirrors.

Abstract: A pulsed laser system includes a laser pump, a laser rod, a reflector interposed between the laser pump and the laser rod, through which energy from the laser pump enters the laser rod, an output reflector through which energy is emitted from the laser rod, a switch interposed between the laser rod and the output reflector, and a control device. The switch, when closed, causes energy to be stored in the laser rod and, when opened, allows energy to be emitted from the laser rod during an emission period. The control device allows a primary laser pulse emitted from the laser rod during the emission period to impinge on a workpiece and blocks from the workpiece secondary laser emission occurring during the emission period after emission of the primary pulse. The pulsed laser system is operated over a range of repetition rates, so as to cause laser energy to be emitted during a plurality of emission periods at each repetition rate.

Abstract: A light emitting device for generating at least one beam of output radiation from an input current of electrons comprises at least two p-n junction devices for converting the input current of electrons into photons, wherein the p-n junction devices are electrically connected in series such that the input impedance of the light emitting device is substantially equal to the sum of the individual impedance of the p-n junction devices. Hence the quantum efficiency of the light emitting device is substantially equal to the sum of the individual quantum efficiencies of the p-n junction devices. In a preferred embodiment, the light emitting device comprises a plurality of p-n junction devices connected in series such that the input impedance of the light emitting device is equal to 50 &OHgr; without the need for additional circuitry or impedance matching elements.

Abstract: The subject of the disclosed art is to prevent a short circuit between plural electrodes caused by soldering in the assembling process for a semiconductor laser element. The constitution for improving the subject is as follows. A semiconductor laser device comprises a semiconductor laser chip having a first electrode and a laser sustaining material, in which the laser sustaining material has electrodes and solder layers connected electrically therewith on the surface where the semiconductor laser chip is mounted, the first electrode of the semiconductor laser chip is connected with the solder layer of the laser sustaining material and at least the solder layer of the laser sustaining material extends from at least one end face in the longitudinal direction of an optical resonator of the semiconductor laser chip to the outside of the optical resonator.

Abstract: A laser-diode-pumped solid-state laser apparatus includes a laser rod, and laser diode devices that generate pumping light. Optical unit such as a reflection mirror and an optical waveguide medium is provided at a position in a laser resonator near a laser optical axis and not blocking the optical axis. A photo-detector detects a quantity of fluorescence generated from solid-state laser medium. The fluorescence quantity is compared with a predetermined value or a previously measured value. Thus degradation status of a laser diode light source is constantly diagnosed.

Abstract: In an external cavity laser, which comprises an FBG section having the Bragg wavelength of light reflected by a grating adjusted to a given wavelength and a laser light emitting device designed to generate light, optically coupled to the FBG section to ensure input and output of the light, and including a high-reflection surface for reflecting the generated light, the light is resonated by a cavity formed between the high-reflection surface and the grating, whereby a laser beam having a given oscillation wavelength is oscillated through a connector. The FBG section is located on an optical path between the laser light emitting device and the connector, and an isolator is located on an optical path between the FBG section and the connector. The isolator serves to absorb and intercept reflected waves or reflected return light from the connector.

Abstract: A semiconductor laser device comprises an optical fiber having an optical fiber grating formed therein, a semiconductor laser having an active layer with a single quantum well, for emitting laser light, and a coupling optical system for coupling the laser light emitted out of the semiconductor laser into the optical fiber. The coupling optical system can include a narrow-band filter for adjusting an incident angle of the laser light emitted out of the semiconductor laser. The optical fiber grating can have a reflection bandwidth wider than or substantially equal to a 3 dB bandwidth of the gain of the semiconductor laser or a spectrum full width at half maximum of the laser light of the semiconductor laser.

Abstract: A surface emitting semiconductor laser capable of operating at high power levels and with high efficiency is formed to emit in a single far-field lobe in a single mode. The laser includes a semiconductor substrate and epitaxial structure including an active region layer and cladding layers. A distributed feedback grating is formed of periodically alternating grating elements to provide optical feedback as a second order grating for the effective wavelength of light generation from the active region. Surface emission in a single lobe pattern may be obtained by forming one edge face of the structure to be reflective and the other face to be antireflective. The semiconductor laser may also be formed to have a symmetric near-field pattern and single lobe surface emission utilizing a phase shift in the 2nd-order distributed feedback grating at its center and with antireflective edge faces.

Abstract: A laser-diode structure whose output is largely single-mode utilizes a ridged top layer that defines an amplification region within an underlying emission layer, and which is provided with grooves that suppress the higher modes.

Abstract: A semiconductor laser includes an active layer stripe including a first semiconductor layer, an active layer, and a second semiconductor layer that are laminated in that order on a substrate and formed into a stripe-shape; a burying layer in which the active layer stripe is buried; and a contact layer formed on the burying layer. The semiconductor laser further includes a monitor stripe that is formed in parallel to the active layer stripe and is composed of the first semiconductor layer only at an output end of the laser, the monitor stripe is buried in the burying layer on which the contact layer is formed, and the active layer stripe and the monitor stripe are isolated electrically by an isolation groove. The width of the active layer stripe can be controlled easily based on the width of the active layer in the monitor stripe as a criterion.

Abstract: The present invention provides a vertical structure semiconductor laser comprising bottom and top cladding layers (1, 2), a light guide (G) superposed on the bottom cladding layer, and a semiconductor active layer (CA). In the invention, the light guide (G) further comprises: a semiconductor bottom guide layer (11) having the following two adjacent bottom parts: an undoped first bottom part (11a) adjacent the central region, and an n-type doped second bottom part (11b) adjacent the bottom cladding layer, a semiconductor top guide layer (12) having the following two adjacent top parts: an undoped first top part (12a) adjacent the central region, and a p-type doped second top part (12b) adjacent the top cladding layer. The first bottom and top parts form a non-doped region (ND) more than 0.5 &mgr;m thick, and the refractive index difference (&Dgr;nopt) between one or each of the cladding layers and the adjacent guide layer is less than 0.02.

Abstract: A method of controlling a tuneable laser that has been characterized with respect to one or more suitable laser operation points. Each operation point is determined by the manner in which the different laser sections are controlled, in order to operate the laser at a predetermined operation point. The voltage across the different laser section is determined for different operation points when controlling the laser, and the voltages across the different laser sections are held constant when the laser is in operation to maintain a predetermined operation point.

Abstract: A programmable multiwavelength modelocked laser system. Embodiments of the system can use a computer, gratings, optical spectrum analyzer and SLM(spatial light modulator) inside of a laser cavity to control output amplitudes and phase of each of the wavelength channels of a multiple wavelength laser system. The programmable control allows for wavelength intensity(amplitude) levels of up to approximately 16 channels to be controlled and evened out. An InGaAsP SOA based modelocked multiwavelength ring laser is stabilized using a programmable liquid crystal spatial light modulator in a feedback control loop. The system produces 16 independent modelocked RZ wavelength channels at 10 GHz with 0.44 dB flatness and 25 psec pulses.

Abstract: A high-speed laser driver for signal noise on the electrical analysis point. The driver includes a power supply, for providing a test voltage in the system; a pulse generator, for providing a test frequency in a noise testing of the system; a regulable test IC with different signal pads capable of regulable testing signal noise with the test frequency from the pulse generator and the test voltage from the power supply in a plurality of built-in specific structures, under the basis of an assigned current standard; and a digital detection device with a display, for displaying and recording the result of the regulable test.