Abstract: A pulsed, mode-locked, picosecond laser having a solid-state laser medium, a saturable absorber (SA), and a passive negative feedback (PNF) element. The SA is “slow,” having an absorption recovery time which is longer than a desired duration of an output pulse. The SA and the PNF element together mode-lock the laser to produce an output pulse or pulses of a given duration. The position of the SA along the beam path and the orientation of the SA with respect to the beam path can be varied to vary the output pulse duration over a wide range.

Abstract: An improved digital trigger circuit has a plurality of data samples extracted from an input electrical signal for each sample clock cycle. The plurality of data samples are compared in parallel with a high threshold level and a low threshold level which provides hysteresis for noise rejection. Also the plurality of data samples are used to determine sub-sample trigger positioning. The comparison outputs are input to a digital trigger logic circuit for identifying a selected trigger event and generating a trigger for the acquisition of data from the input electrical signal for analysis and display. The digital trigger logic provides edge event triggering, pulse width triggering and transition time triggering, among others.

Abstract: A loop is formed with an optical fiber by providing a gain medium having a gain with respect to an oscillation wavelength. Light retrieved by the optical circulator 13 from the optical fiber loop is enlarged and projected to a mirror 23. A diffraction grating 25 is provided with respect to the light reflected in the mirror. The diffraction grating 25 has a Littrow arrangemnt wherein the light is reflected in a same direction as incident light. A selected wavelength is changed in accordance with an incident angle with respect to the diffraction grating 25. Therefore, when the mirror 23 is rotated so as to change the selected wavelength, the oscillation wavelength can be changed at high speed.

Abstract: In one aspect, a VCSEL includes a base region that has a vertical growth part laterally adjacent a first optical reflector and a lateral growth part that includes nitride semiconductor material vertically over at least a portion of the first optical reflector. An active region has at least one nitride semiconductor quantum well vertically over at least a portion of the lateral growth part of the base region and includes a first dopant of a first electrical conductivity type. A contact region includes a nitride semiconductor material laterally adjacent the active region and a second dopant of a second electrical conductivity type opposite the first electrical conductivity type. A second optical reflector is vertically over the active region and forms with the first optical reflector a vertical optical cavity overlapping at least a portion of the at least one quantum well of the active region. A method of fabricating a VCSEL also is described.

Abstract: A surface emitting semiconductor laser includes a laminate of semiconductor layers emitting multimode laser light, and a block member blocking light of a specific mode among the multimode laser light emitted from the laminate.

Abstract: In case of driving each of light emitting parts of a surface emitting laser, each of light emitting parts is made to be in forward-bias state and switches appropriately change bias voltage, which is lower than laser oscillation threshold voltage, and drive voltages, which are not less than the laser oscillation threshold voltage to directly apply the changed voltage to each of drive ends of the light emitting parts. Whereby, each of light emitting parts is driven.

Abstract: Methods and apparatus for managing thermal loads on a laser gain medium and for boosting the output power of a diode pumped laser are disclosed. The short-term average pumping power to the gain medium is increased, to provide a burst of pumping energy to the laser gain medium. A subsequent short-term reduction in the average pumping power then allows the gain medium to cool to a desired state steady level. The average pumping power is then increased to maintain this steady state level until the next burst is desired. For example, a pulse of current may be applied to a laser diode at a first current level I1 for a first time interval ?t1, where I1 exceeds a nominal current value Inom by an amount ?I1. The current to the laser diode is reduced to a second current level I2 for a second time interval ?t2, where Inom exceeds I2 by an amount ?I2. To balance the thermal load on the diode an integral of ?I1 over the time ?t1 is approximately equal in magnitude to an integral of ?I2 over the time ?t2.

Abstract: The present invention relates to optical systems, beam expanding assemblies, line narrowing modules, and lasers having refractive optical elements with wavefront correcting optical surfaces. The present invention enables the skilled artisan to provide optical systems, beam expanding assemblies, line narrowing modules, and lasers having improved optical properties, such as, in the case of lasers, narrow linewidth at high power, and substantially planar wavefronts.

Abstract: Purely gain-coupled diffraction gratings may be realized for use in QCLs and other edge emitting lasers that lack a typical p-n junction. The periodic, typically heavily n-doped regions of doped diffraction gratings are replaced with p-type regions having significantly lower doping.

Abstract: A method of controlling a laser diode measures an average light output power of the laser diode and compares the average light output power to a desired average light output power within a target range. If the average light output power is not within the target range, the slope efficiency is determined by measuring two light output powers at two different bias conditions. Each of the two light output powers is greater than a selected minimum light output power, which insures that each measurement occurs within the slope efficiency portion of the laser diode curve. A new bias current for the laser diode is calculated based on the measured slope efficiency so as to produce a new average light output power within the target range.

Abstract: A laser diode array assembly. The assembly includes a plurality of vertical emitting laser diodes. Each laser diode has a vertical emitting surface and an exposed substrate surface opposite from the emitting surface. Each vertical emitting surfaces emit a laser beam. The assembly further includes one or more nozzles that directly spray a liquid onto the exposed substrate surfaces.

Abstract: A voltage dividing apparatus for preventing sudden increases in power to a laser diode includes a laser diode module, a laser-driving unit and a Zener diode. The laser diode module includes a laser diode for receiving a driving current to emit light, and a photo diode for receiving the light emitted from the laser diode and transferring the light signal into a voltage signal. The voltage signal is fed back to the laser diode module for automatically balancing the power of the laser diode. The laser-driving unit is used for driving the laser diode to output power. When the circuit shorts, two voltage-dividing resistors and the Zener diode disable the laser-driving unit to protect the laser diode. It blocks the laser diode's outputting power to prevent the outputting power from suddenly increasing and prevent the laser with strong power from hurting a user's eyes.

Abstract: A surface emitting semiconductor laser diode of a tunnel junction type includes a semiconductor substrate, a first reflector, a second reflector, an active region disposed in series between the first and second reflectors, and a tunnel junction region disposed in series between the first and second reflectors. The tunnel junction region includes a first semiconductor layer of a first conductive type and a second semiconductor layer of a second conductive type that forms a junction with the first semiconductor layer, the first semiconductor layer being composed of a supper-lattice layer that at least partially includes aluminum and is partially oxidized.

Abstract: A high power narrow band, high repetition rate laser light source optical improvement apparatus and methods are disclosed with a fast angularly positionable mirror having a mirror mounting frame, a reflective optic with a coefficient different from that of the mounting frame, at least one flexure mount fromed in the mounting frame that is flexible having flexure arm attached the flexture to the mounting frame. The apparatus may include a flexure force mechanism having an elongated rod. The force mechanism may pre-stress the flexure. The mirror maybe a grating which includes a substrate with metallic layer formed on the substrate, and a protective coating made of silica formed on the reflective metallic layer. The grating maybe actively tuned using an electro- or magneto-sensitive element. Oxides of the metal in the reflective layer may be removed by a hydrogen purge system exposed to deep ultraviolet radiation.

Abstract: In an laser oscillator (100), a blower (10, 20, 120) for circulating a laser medium between an electric discharge tube (102) and a circulating passage (104) includes: a casing (12) having a suction port (12a) and an exhaust port (12b); and a blade (18) pivotally supported in the casing (12) so that the blade (18) can face the suction port (12a) and the exhaust port (12b). The blade (18) is formed into a shape in which a diameter of the blade (18) is different at a position on a cross section perpendicular to a rotary central line (O), and a gap (Go) between a portion, in which a diameter of the blade (18) is relatively large, and the casing is larger than a gap (Gi) between a portion, in which a diameter of the blade (18) is relatively small, and the casing. Due to the foregoing, a highly reliable blower used for a laser oscillator, the reduction of the blower efficiency of which is suppressed to be as small as possible, can be provided.

Abstract: A semiconductor device has a main structure member laminated on a first conductivity-type semiconductor substrate. On the main structure, there is formed a first substructure member, the entirety of which, including lowermost layer, is second conductivity-type. On the main structure member, there is also formed a second substructure member spatially separated from the first substructure member. The second substructure member has a current block layer of a semiconductor layer on the second conductivity-type structure identical to the first substructure member. In the semiconductor device, there is further provided a p-side electrode formed on the first and second substructure members and between the first and second substructure members to connect therebetween.

Abstract: A tunable semiconductor laser includes gain medium, wavelength-selective element and a laser mode matching element. The wavelength-selective element comprises a first light absorbing plate operatively coupled to the laser mode matching element and provided with an array of high reflectivity mirrors as well as a second light absorbing plate with an array of narrow band pass filter mirrors operatively coupled to the high reflectivity mirror array of the first plate. The narrow band pass filter mirror array is disposed over a respective array of apertures in the second plate. The wavelength-selective element also comprises a light reflective plate with an array of retroreflectors and a third light absorbing plate with an array of apertures operatively disposed between the aperture array of the second plate and the retroreflector array.

Abstract: A semiconductor optoelectronic device includes at least one cavity and one multilayered interference reflector. The cavity is designed preferably to possess properties of an antiwaveguiding cavity, where no optical modes propagate in the lateral plane. The existing optical modes are the modes propagating in the vertical direction or in a direction tilted to the vertical direction at an angle smaller than the angle of the total internal reflection at the semiconductor/air interface. This design reduces the influence of parasitic optical modes and improves characteristics of optoelectronic devices including vertical cavity surface emitting lasers, tilted cavity lasers emitting through the top surface or the substrate, vertical or tilted cavity resonant photodetectors, vertical or tilted cavity resonant optical amplifiers, and light-emitting diodes.

Abstract: A multi-section laser diode control system comprising a multi-section laser diode (10), microprocessor controller (24), digital-to-analogue converter (28), driver circuit (30) and wavelength locker (14) is modified by inclusion of a locking circuit (40) which generates an analogue correction signal . . . 1 V ph responsive to measurements of the laser output made by the wavelength locker. The analogue correction signal is added to the preset phase voltage V ph asserted by the microprocessor controller to provide fast feedback that bypasses the microprocessor controller. This novel feedback is made possible by avoiding the use of the standard prior art control algorithm which requires a division calculation to be performed. Instead, novel control algorithms based purely on additions, subtractions and multiplications are used. The laser can thus be locked to its target output frequency without having to place slow analogue-to-digital and digital-to-analogue converters in the feedback control path.

Abstract: The present invention provides a semiconductor laser device capable of improving reproducibility and electrical properties of the device, and a manufacturing method thereof. The semiconductor laser device according to the invention includes a first p type AlGaInP-based clad layer formed on an active layer, and a second p-type AlGaInP-based clad layer formed on the first p-type AlGaInP-based clad layer and having a ridge structure. The first p-type AlGaInP-based clad layer is Zn-doped with a concentration that restrains Zn diffusion into the active layer, and the second p-type AlGaInP-based clad layer is Mg-doped with a concentration higher than that of the first AlGaInP-based clad layer.