Abstract: A purpose of this invention is to suppress radiation noise while satisfying demands for higher speeds and higher image qualities of a semiconductor laser driving device in a laser beam printer or the like. A laser driving circuit includes a first wiring pattern and a second wiring pattern which are connected to a main wiring pattern, a first circuit which is connected to the first wiring pattern and has a semiconductor laser element (7) and a laser driving device for driving the semiconductor laser element, a second circuit which is connected to the second wiring pattern, has a compensation element and a compensation driving device, and compensates for noise in the first circuit, and a common mode choke coil which is connected to the first and second wiring patterns and selectively increases impedances to in-phase signal components in a signal flowing through the first wiring pattern and the first circuit and a signal flowing through the second wiring pattern and the second circuit.

Abstract: A semiconductor laser driving unit is disclosed that includes a first part generating a bias current; a second part generating a first current for causing the semiconductor laser to emit light, and outputting the first current to the semiconductor laser in accordance with an input control signal; a third part performing initialization to detect a light emission characteristic of the semiconductor laser, and causing the second part to generate a second current of a value obtained from the detected light emission characteristic; and a fourth part causing the second part to generate the first current in which a set offset current is added to the second current. The first part detects the amount of light emission of the semiconductor laser, and generates and outputs the bias current so that the amount of light emission produced by the sum of the bias current and the first current is a predetermined value.

Abstract: Various circuits and methods are provided for driving a laser. A laser driver circuit is configured to generate a modulated current through a laser. Also, a peak current source is employed to generate a peak current that is differentially applied to the laser to enhance a transition rate of the laser.

Abstract: Various embodiments described herein relate to a laser source for producing a pulsed laser beam comprising a plurality of ultrashort optical pulses having a variable repetition rate. In one embodiment, the laser source comprises a fiber oscillator, which outputs optical pulses and a pulse stretcher disposed to receive the optical pulses. The optical pulses have an optical pulse width. The pulse stretcher has dispersion that increases the optical pulse width yielding stretched optical pulses. The laser source further comprises a fiber amplifier disposed to receive the stretched optical pulses. The fiber optical amplifier has gain so as to amplify the stretched optical pulses. The laser source includes an automatically adjustable grating compressor having dispersion that reduces the optical pulse width. The grating compressor automatically adjusts this dispersion for different repetition rates.

Abstract: A driver laser for EUV light source apparatus which driver laser simultaneously achieves short-pulsing and multi-line oscillation. The driver laser includes: a short-pulse multi-line oscillated CO2 laser oscillator having a device that shortens width of pulses included in a laser beam to be output and a device that suppresses amplitude of an oscillation spectrum exhibiting an energy peak value; and at least one amplifier that inputs the laser beam output from the short-pulse multi-line oscillated CO2 laser oscillator and amplifies the input laser beam to output the amplified laser beam.

Abstract: This invention relates to a method and system to detect hysteresis/unstable regions of multi-section lasers. The method comprises the steps of obtaining a first set of measurement values for the output of the laser diode by increasing a first current through a range of values in a positive direction, increasing a second control current by a step, obtaining a second set of measurement values for the output of the laser diode by decreasing the first control current through a range of values in a negative direction, and increasing a second control current by a step. The process is repeated until a sufficient range of the second control currents has been used to provide resultant data which can then be processed in order to identify regions of hysteresis of the laser diode.

Abstract: A laser assembly comprises a substrate and two or more lasers. The substrate has a substantially planar surface region and a raised feature. The raised feature comprises two or more reflective surfaces. Each of the two or more lasers is mounted to the substantially planar surface region and is configured to emit a laser beam directed towards the raised feature at a nonzero tilt angle in relation to the substantially planar surface region.

Abstract: The present invention provides a nitride semiconductor laser element, comprising: a nitride semiconductor structure having a first nitride semiconductor layer, a second nitride semiconductor layer, and an active layer provided between the first and second nitride semiconductor layers; a cavity end face provided to the nitride semiconductor structure; and a protective film having a hexagonal crystal structure, and having a first region provided on a first crystal surface of the nitride semiconductor structure in the cavity end face and a second region provided on a second crystal surface in the surface of at least one of the first and second nitride semiconductor layer, the first and second regions of the protective film are oriented in the same axial direction as that of the respective first and second crystal surfaces.

Abstract: A method is provided for determining a laser threshold of a laser diode, which is operated by a drive circuit as a function of a first signal in a first feedback and a second signal in a second feedback, the first feedback being supplied via an optical coupling of an optical output signal of the laser diode.

Abstract: A driver laser for EUV light source apparatus which driver laser simultaneously achieves short-pulsing and multi-line oscillation. The driver laser includes: a short-pulse multi-line oscillated CO2 laser oscillator having a device that shortens width of pulses included in a laser beam to be output and a device that suppresses amplitude of an oscillation spectrum exhibiting an energy peak value; and at least one amplifier that inputs the laser beam output from the short-pulse multi-line oscillated CO2 laser oscillator and amplifies the input laser beam to output the amplified laser beam.

Abstract: The invention relates to a method and system for providing a set of continuous tuning regions from a discontinuously tuned laser, by providing a wavelength reference having at least first and second resonance peaks, sweeping the laser across a pre-determined wavelength range of the wavelength reference, and defining, within the laser sweep, one or more regions of continuous tuning operation of the laser, each of the regions corresponding to a response of the laser between adjacent resonance peaks of the wavelength reference. The advantage of the invention is that it provides a way for stitching together continuous regions of a multi-section tunable laser in an efficient and accurate manner.

Abstract: A regenerative amplifier includes a gain-medium that is optically pumped by CW radiation. The amplifier has primary resonator for amplifying pulses. The primary resonator has an optical switch for opening and closing the primary resonator. The amplifier has a secondary resonator that includes the gain-medium but not the optical switch. When the primary resonator is closed by the optical switch, and pulses are not being amplified, CW radiation is generated in the secondary resonator and prevents the gain-medium from being saturated. When the optical switch is operated to cause the primary resonator to amplify pulses, generation of CW radiation in the secondary resonator ceases.

Abstract: The present invention relates to the tailoring the reflectivity spectrum of a sampled-grating distributed Bragg reflector (SGDBR) by applying digital sampling theory to choose the way each reflector is sampled. The resulting mirror covers a larger wavelength span and has peaks with a larger, more uniform, coupling constant (?) than the mirrors produced using conventional approaches. The improved mirror also retains the benefits of the sample grating approach. Additionally, most of the embodiments are relatively simple to manufacture.

Abstract: Objects are achieved by an optical semiconductor device comprising: a structure 61 including a substrate 50, a diffraction grating 52a, an active layer 54 and a refractive index control layer 60; and an laser element 100 including an electrode 92a for the active layer, an electrode 92b for the refractive index control layer and an electrode 92c for switching, wherein a pre-bias current is previously supplied from the electrode 92a for the active layer to the active layer 54 in a state where a switching current is not supplied from the electrode 92c for switching to the active layer 54, and then while a current Idrive for activation is supplied from the electrode 92a for the active layer to the active layer 54, the laser element 100 is turned on by supplying the switching current Isw from the electrode 92c for switching to a part of the active layer 54, as well as turning off the laser element 100 by halting the supply of the switching current Isw.

Abstract: A semiconductor laser has first and second diffractive grating regions. The first diffractive grating region has segments, has a gain, and has first discrete peaks of a reflection spectrum. The second diffractive grating region has segments combined to each other, and has second discrete peaks of a reflection spectrum. Each segment has a diffractive grating and a space region. Pitches of the diffractive grating are substantially equal to each other. A wavelength interval of the second discrete peaks is different from that of the first discrete peaks. A part of a given peak of the first discrete peaks is overlapped with that of the second discrete peaks when a relationship between the given peaks of the first discrete peaks and the second discrete peaks changes.

Abstract: A system for real-time linewidth reduction in an optical source includes a laser device comprising a back facet, wherein the laser device receives a modulated input current and generates an optical output signal; an etalon device disposed adjacent to the back facet of the laser device, wherein the etalon device receives an optical feedback output signal from the back facet of the laser device, and wherein the etalon device monitors the optical feedback output signal for changes in frequency and, if they exist, generates an optical correction output signal; a photo-detector device disposed adjacent to the etalon device, wherein the photo-detector device receives the optical feedback and correction output signals, and wherein the photo-detector device converts the optical feedback and correction output signals into an electrical signal; and a feedback correction loop coupled to the photo-detector device, wherein the feedback correction loop receives the electrical signal from the photo-detector device and gener

Abstract: A vertical external cavity surface emitting laser (VECSEL) in which the full-width at half maximum (FWHM) of laser light is reduced by two etalon filter layers to improve the efficiency of second harmonic (SHG) crystal is provided. The VECSEL includes: a laser chip for generating laser light; a first etalon filter layer formed on the laser chip; a second etalon filter layer that is formed on the first etalon filter layer and has a different refractive index than the first etalon filter layer; a first mirror separated from and disposed obliquely to the laser chip; a second mirror for reflecting the laser light reflected from the first mirror back to the first mirror to form a cavity with the laser chip; and an SHG crystal disposed along an optical path between the first and second mirrors and doubles the frequency of the laser light generated in the laser chip.

Abstract: Laser power control arrangements interrupt power to a laser used in electro-optical readers upon detection of an over-power condition not conforming to preestablished regulatory standards. In one embodiment, during an operational mode, a difference between laser drive currents at two operating points is compared to a difference between laser drive currents at the same two operating points during a calibration mode. The over-power condition is recognized when the difference during the operational mode exceeds the difference during the calibration mode by a predetermined amount. In another embodiment, the laser is only energized to emit the beam at a reduced power level well below regulatory standards for staring at even if a motor drive failed.

Abstract: A nitride semiconductor laser device comprises a nitride semiconductor substrate (101); a nitride semiconductor lamination structure that has an n-type semiconductor layer (102), an active layer (104) and a p-type semiconductor layer (103) laminated on or above the nitride semiconductor substrate (101), and has a stripe-shaped waveguide region for laser light; and end surface protective films (110) on the both end surfaces substantially perpendicular to the waveguide region. In the nitride semiconductor laser device, the nitride semiconductor substrate (101) has a luminescent radiation region (112) that absorbs light emitted from the active layer (104) and emits luminescent radiation with a wavelength longer than the wavelength of the emitted light, and the end surface protective films (110) have a high reflectivity for the wavelength of the luminescent radiation from the luminescent radiation region (112).

Abstract: Provided is a distributed feedback semiconductor laser structure including: a first clad layer; a first ridge waveguide formed on the first clad layer; an active layer formed on the first ridge waveguide; a second ridge waveguide formed on the active layer; a second clad layer formed on the second ridge waveguide; an ohmic contact layer formed on the second clad layer; and a plurality of gratings formed in at least one of the first and second clad layers, making a predetermined angle with the first ridge waveguide or the second ridge waveguide, and periodically arranged in a longitudinal direction of the first or second ridge waveguide. As a result, a general hologram lithography process capable of mass production is applied to the present invention so that process time can be reduced. Also, a distributed feedback semiconductor laser structure using a quantum-dot active layer that does not require an additional process for obtaining a pure single-wavelength is provided.