Abstract: A photonic integrated circuit (PIC) chip comprising an array of modulated sources, each providing a modulated signal output at a channel wavelength different from the channel wavelength of other modulated sources and a wavelength selective combiner having an input optically coupled to received all the signal outputs from the modulated sources and provide a combined output signal on an output waveguide from the chip. The modulated sources, combiner and output waveguide are all integrated on the same chip.

Abstract: To provide an optical clock signal extracting device with a simple configuration, by which an optical clock signal may be extracted without depending on the polarization direction of an input optical signal. A current is injected to a gain region 30 through an n-type common electrode 12 and a p-type electrode 24 in the gain region 30 by a constant current source 28. A reverse-bias voltage is applied by a constant voltage source 26 to a saturable absorption region 32 through the p-type electrode 12 and the n-type common electrode 72 in the saturable absorption region 32. An optical waveguide 16 in the gain region is formed with bulk crystal or a quantum well structure into which extension strain is introduced, and an optical waveguide 18 in the saturable absorption region is formed with a quantum well structure into which extension strain is introduced.

Abstract: The quality of pulses output from laser systems such as super-pulsed CO2 slab lasers can be improved using half-wavelength electro-optic modulators (EOMs), in combination with thin film polarizers (TFPs). A voltage applied across a CdTe crystal of the EOM rotates the polarization of a pulse passing through the EOM by 90°. The polarization determines whether the pulse passes through, or is redirected by, the TFP. The voltage applied to the crystal can be pulsed to prevent a drop in charge, which could allow radiation to leak to the application. A totem pole switch used to apply voltage to the EOM can receive a pulsed voltage for improved performance. Directing by the EOM allows pulses to be clipped at the front/back end(s), split into portions, and/or directed to separate scanners. Directing pulses or pulse portions to different scanners can increase the output of systems such as hole drilling systems.

Abstract: Low cost implementation of broadband upstream transmission for local and access network applications is made possible through the use of modulated downstream signals in a wavelength division multiplexed (WDM) passive optical network (PON) to injection-lock vertical-cavity surface-emitting lasers (VCSELs) for operation as stable, uncooled, and directly-modulated upstream transmitters. By way of example and not limitation, an optical network unit comprises: downstream input, photoreceiver, tunable laser, upstream output, and means for directionally coupling the downstream input into the tunable laser for modulating the output wavelength which is coupled to the upstream output.

Abstract: The present invention uses an intra-cavity modulation approach to modulate a laser transmitter at bandwidths greater than a few gigahertz (GHz) in a non-ambiguous waveform by chirping the laser and simultaneously mode locking. Accordingly, the inventive system includes a source of a beam of electromagnetic energy; a mechanism for mode locking the beam; and an arrangement for chirping the beam. In the illustrative embodiment, the source is a laser. The mode locking mechanism may be an active element or a passive element. The beam is chirped with a translation mirror. The translation mirror may be driven with a piezo-electric drive coupled. In the best mode, the carrier is chirped with an electro-optical crystal disposed in the cavity of the laser. The laser is chirped to the free-spectral range limit, which is typically a few hundred megahertz, by scanning the optical length of the laser resonator.

Abstract: Both a system and method are provided for modulating the intensity of an output beam generated by semiconductor laser. The exemplary system includes a source of pulsating current connected to the laser that generates a pulsating beam of laser light, an external modulator having an input that receives the pulsating beam, and an output controlled by pulsating control signal, wherein the output beam transmitted by the external modulator output is modulated by changing a relative phase angle between the pulsating current powering the laser, and the control signal of the external modulator over time. The external modulator may be an intensity-type modulator whose output is controlled by a gate signal having a constant phase, and the source of pulsating current powering the laser may be variable phase in order to modulate the output beam with an external modulator having a simple structure.

Abstract: Electroabsorption-modulated Fabry-Perot lasers and methods of making the same are described. In one aspect, a light source includes a Fabry-Perot (FP) laser that is operable to generate multimode laser light, an electroabsorption modulator (EAM) that is configured to selectively absorb and transmit laser light traveling therethrough, and an optical isolator. The optical isolator is on an optical path between the FP laser and the EAM. The optical isolator is configured to transmit laser light traveling along the optical path from the FP laser to the EAM.

Abstract: Apparatus for providing optical radiation includes a pump source and at least one first amplifying waveguide. The first amplifying waveguide emits optical radiation in excess of 1400 nm when pumped by the pump source. In one embodiment, the pump source can include a plurality of laser diodes and a plurality of second amplifying waveguides. In this arrangement the first amplifying waveguide is pumped by the second amplifying waveguides, the second amplifying waveguides are pumped by the laser diodes, and the second amplifying waveguides are configured to improve the beam quality of radiation emitted by the laser diodes.

Abstract: An optical transmitter is discloses having a gain section and a phase section. The phase section is modulated to generate a frequency modulated signal encoding data. The frequency modulated signal is transmitted through an optical spectrum reshaper operable to convert it into a frequency and amplitude modulated signal. In some embodiments, a driving circuit is coupled to the phase and gain sections is configured to simultaneously modulate both the phase and gain sections such that the first signal is both frequency and amplitude modulated.

Abstract: The configurations of an electro-optic Bragg deflector and the methods of using it as a laser Q-switch in a Q-switched laser and in a Q-switched wavelength-conversion laser are provided. As a first embodiment of the present invention, the electro-optic Bragg deflector comprises an electrode-coated electro-optic material with a spatially modulated electro-optic coefficient. When a voltage is supplied to the electrodes, the electro-optic material behaves like a Bragg grating due to the electro-optically induced spatial modulation of the refractive index. The second embodiment of the present invention relates to an actively Q-switched laser, wherein the electro-optic Bragg deflector functions as a laser Q-switch. The third embodiment of the present invention combines the Q-switched laser and a laser-wavelength converter to form a Q-switched wavelength-conversion laser, wherein the EO Bragg deflector can be monolithically integrated with a quasi-phase-matching wavelength converter in a fabrication process.

Abstract: Disclosed herein is a laser light source device including a pumping light source; a pair of resonator mirrors; a laser medium and a wavelength converting element within a resonator formed by the resonator mirrors; the laser medium being pumped by light in a transverse multi-mode pattern, the wavelength converting element being irradiated with a linear fundamental wave obtained by oscillation of the laser medium, and a linear converted wave being output; a reflecting part for folding back a resonant light path, the reflecting part being disposed on the light path between the laser medium and the wavelength converting element; an end surface of one of the laser medium and the wavelength converting element being formed as an inclined surface at other than a Brewster angle; and a polarizing film disposed on the inclined surface.

Abstract: Systems, devices and methods of generating both a precision electrical timing signal as well as a precision optical timing signal. A novel, modified opto-electronic loop oscillator is used to drive a harmonic mode-locked laser. A novel opto-electronic loop has a larger “Q” factor by increasing the electrical loop oscillating frequency ?0 by using a beat note created by the selection of two optical longitudinal modes from the mode-locked laser. The beat note is detected and divided down to drive a modulator that mode-locks the laser. The frequency division stage also reduces the noise.

Abstract: Semiconductor electrooptic medium shows behavior different from a medium based on quantum confined Stark Effect. A preferred embodiment has a type-II heterojunction, selected such, that, in zero electric field, an electron and a hole are localized on the opposite sides of the heterojunction having a negligible or very small overlap of the wave functions, and correspondingly, a zero or a very small exciton oscillator strength. Applying an electric field results in squeezing of the wave functions to the heterojunction which strongly increases the overlap of the electron and the hole wave functions, resulting in a strong increase of the exciton oscillator strength. Another embodiment of the novel electrooptic medium includes a heterojunction between a layer and a superlattice, wherein an electron and a hole in the zero electric field are localized on the opposite sides of the heterojunction, the latter being effectively a type-II heterojunction.

Abstract: An optical transmitter comprises an array of modulated sources having different operating wavelengths approximating a standardized wavelength grid and providing signal outputs of different wavelengths. Signal outputs of the modulated sources are optically coupled to inputs of the wavelength selective combiner to produce a combined signal output from the combiner. The wavelength selective combiner has a wavelength grid passband response approximating the wavelength grid of the standardized wavelength grid. A first wavelength tuning element is coupled to each of the modulated sources and a second wavelength tuning element is coupled to the wavelength selective combiner. A wavelength monitoring unit is coupled to receive a sampled portion the combined signal output from the wavelength selective combiner. A wavelength control system is coupled to the first and second wavelength tuning elements and to the wavelength monitoring unit to receive the sampled portion of the combined signal output.

Abstract: The so-called single-longitudinal mode of operation of a tunable laser beam source requires active control of the band-pass filters mounted in the laser resonator. As a rule, this entails one, or a combination of several filter elements, as for example birefringent filters, as well as etalons. In either case, the band-pass filter needs to be so adjusted as to locate precisely one of the feasible longitudinal modes of the laser at the exact maximum transmission of the band-pass filter. The invention consists in regulating such filter setting by way of a program-controlled digital signal processor DSP in such a way that the DSP modulates the filter element with an adjustable frequency, and such regulation exploits the phase of the laser intensity fluctuations induced thereby to regulate the optimal position of the band-pass filter.

Abstract: The invention relates to an optical delay module for lengthening the propagation path of a light beam comprises a first spherical mirror and a second spherical mirror, the first spherical mirror and the second spherical mirror having equal radii of curvature, the first and the second mirror being arranged on a common axis of symmetry with concave sides of the first and second mirrors being situated opposite one another at a distance from one another which corresponds to the radii of curvature of the first and second mirrors. The module also includes a coupling-in area for coupling the light beam into a space between the first and second mirrors and a coupling-out area for coupling the light beam out of the space between the first and second mirrors.

Abstract: Electro-optic amplitude varying elements (AVEs) or electro-optic multi-function elements (MFEs) are integrated into signal channels of photonic integrated circuits (PICs) or at the output of such PICs to provide for various optical controlling and monitoring functions. In one case, such PIC signal channels may minimally include a laser source and a modulator (TxPIC) and in another case, may minimally include a photodetector to which channels, in either case, an AVE or an MFE may be added.

Abstract: A laser drive circuit may be used to induce high limit clipping corresponding to natural low limit clipping in a laser, such as a laser diode, to reduce even order distortion such as composite second order (CSO) distortion. A drive current input may be provided to the active region of the laser to produce a modulated optical output in response to the drive current input. The laser drive circuit may include a current clamp at the drive current input, which clamps the drive current to provide the high limit clipping. The current clamp may receive an input current including current from a RF signal provided by a RF source together with a bias current provided by a bias current source.

Abstract: Provided is a method for driving a surface emitting semiconductor laser including an active region that generates light, a resonator structure disposed such that it sandwiches the active region, and a driving electrode that provides power to the active region. The surface emitting semiconductor laser has an internal resistance defined by voltage and current applied to the driving electrode. The method includes applying a modulation signal to the driving electrode, in which the modulation signal has a current amplitude defined by a first current value and a second current value that is greater than the first current value. The modulation signal is in a negative gradient region in which the internal resistance decreases in contrast to the increase of the current.

Abstract: A photonic integrated circuit (PIC) chip comprising an array of modulated sources, each providing a modulated signal output at a channel wavelength different from the channel wavelength of other modulated sources and a wavelength selective combiner having an input optically coupled to received all the signal outputs from the modulated sources and provide a combined output signal on an output waveguide from the chip. The modulated sources, combiner and output waveguide are all integrated on the same chip.

Abstract: A SAG technique is used to grow the ridge structure in a photonic semiconductor device, such as an electroabsorption modulator integrated with a distributed feedback laser (EML) assembly. The adoption of this SAG technique to grow the ridge structure results in the formation of a self-assembled and self-aligned ridge structure that has a very precise configuration. The use of this process enables straight, bent and tilted ridge structures to be formed with high precision. In addition, because the ridge structure is self-assembled and self-aligned, a lesser number of processing steps are required to create the photonic device in comparison to the known approach that uses wet chemical etching techniques to form the ridge structure. The high precision of the ridge structure and the lesser number of processing steps needed to create the device increase manufacturing yield and allow overall cost of the device to be reduced.

Abstract: A laser control apparatus and control method thereof includes multiple laser elements, a photodetector for monitoring optical outputs of the laser elements, a modulation. circuit for modulating with respect to each laser element based on data, a first drive source for applying a bias current to each laser element, a second drive source for generating a modulation current in the modulation circuit, and a controller for controlling the first drive source and the second drive source to couple an amount of a variation of a drive current as a test current to the bias current and the modulation current and for controlling the bias current according to an amount of variation of the optical output which occurs by coupling of the test current and an amount of the bias current.

Abstract: An optical semiconductor device with a semiconductor laser formed over a semiconductor substrate, and a modulator formed over the semiconductor substrate and continuously arranged with the semiconductor laser, wherein the semiconductor laser includes a first region having a diffraction grating with a phase shift, a second region arranged between the first region and the modulator, and in which the diffraction grating is not formed, and a common active layer formed over the first region and the second region, a first electrode injecting a current into the common active layer.

Abstract: A high power pulsed optical source includes a multi-port optical circulator and a seed source coupled to a first port of the multi-port optical circulator. The seed source is adapted to provide amplified spontaneous emission. The high power pulsed optical source also includes a first reflective device coupled to a second port of the multi-port optical circulator and a first double-pass optical amplifier coupled at a first end to a third port of the multi-port optical circulator and coupled at a second end to an amplitude modulator. The high power pulsed optical source also includes a second reflective device coupled to the amplitude modulator and an output port coupled to a fourth port of the multi-port optical circulator.

Abstract: The present invention relates to a strong distributed feedback semiconductor laser. More specifically, the invention implements a top optical waveguide (2) for semiconductor lasers having a surface metallic grating (5) making it possible to obtain a stable and controlled distributed feedback, using a simple and robust technology. In the inventive laser, which comprises an active area (1) having an effective refractive index (neff) in which a light wave is propagated with a wavelength (?), the top waveguide (2) is made of a weakly-doped material and the periodic grating (5) depth (p) is [ ? 4 × neff ] plus or minus 50%, the low precision needed being one of the advantages of the inventive laser.

Abstract: A laser system using ultrashort laser pulses is provided. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and a spectrometer. Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and a SHG crystal. In yet another aspect of the present invention, a multiphoton intrapulse interference phase scan system and method characterize the spectral phase of femtosecond laser pulses. Fiber optic communication systems, photodynamic therapy and pulse characterization tests use the laser system with additional aspects of the present invention.

Abstract: According to methods and apparatus described herein, multimode laser source capable of emitting a diffraction-limited beam of various shapes (including single-lobe shape) can be realized. An optical apparatus for generating a such diffraction-limited beam comprises a spatial phase modulator for spatially modulating a spectrally dispersed optical signal emitted from a semiconductor laser into a combined-mode optical signal, wherein the lateral modes of the optical signal from the laser are combined into a diffraction-limited beam. Also, a coupling optical system is provided for wavelength-demultiplexing the multimode optical signal before the multimode optical signal is spatially modulated by the spatial phase modulator, and also for wavelength-multiplexing the combined-mode optical signal.

Abstract: A Q-modulated semiconductor laser comprises an optical gain section and an electro-absorptive modulator section, separated by a vertically etched air gap acting as a partially reflecting mirror. The modulator section is placed inside an anti-resonant Fabry-Perot cavity and acts as the rear reflector of the laser. The change of the absorption coefficient in the modulator section results in a change in the Q-factor of the laser, and consequently the lasing threshold and output power. Different embodiments are disclosed, which involve a distributed feedback (DFB) laser, a Fabry-Perot laser, a distributed Bragg reflector (DBR) laser, or a wavelength switchable multi-cavity laser. The integrated Q-modulated laser has advantages of high speed, high extinction ratio, low wavelength chirp and low cost.

Abstract: A detuned duo-cavity laser-modulator device and method are provided which include lower, middle and upper reflectors, a gain region and an absorber region integrated into a semiconductor die. The middle reflector is disposed between the lower and upper reflectors. Together, the lower and middle reflectors define a first resonant cavity, while the upper and middle reflectors define a second resonant cavity. A gain region is disposed within a laser cavity of the resonant cavities to generate an optical carrier wave, while an absorber region is disposed within a modulator cavity of the resonant cavities to modulate a signal on the optical carrier wave. The laser and modulator cavities are detuned resonant cavities, with the detuning of the laser and modulator cavities being selected to minimized change in reflection from the modulator cavity to the laser cavity when the absorber region modulates the signal on the optical carrier wave.

Abstract: A tunable pulsed laser source comprising a seed source adapted to generate a seed signal and an optical circulator. The optical circulator includes a first port coupled to the seed source, a second port, and a third port. The laser source also includes an amplitude modulator characterized by a first side and a second side. The first side is coupled to the second port of the optical circulator. The laser source further includes a first optical amplifier characterized by an input end and a reflective end including a spectral-domain reflectance filter. The input end is coupled to the second side of the amplitude modulator. Moreover, the laser source includes a second optical amplifier coupled to the third port of the optical circulator.

Abstract: An optically active element, such as a photonic crystal, is formed by creating a matrix (1) in which an optically active material is dispersed, and generating one or more void structures (2, 3) in the matrix. The matrix (1) may comprise polymer dispersed liquid crystal. The void structures (2, 3) may be generated by laser ablation. Properties of the optically active element may be tuned by thermal effects, or via the application of electric, magnetic, or polarised electromagnetic fields. The element may be adapted for use in beam steering, fluid detection, tunable lasers, polarisation multiplexing, and optical switching.

Abstract: A light source that emits light includes light source units, each emitting a plurality of light beams parallel to one another, the plurality of light beams including first and second light beams, and a beam distance adjustment element that is an optical element made of a light-transmissive material. The beam distance adjustment element is configured to adjust the distance between the first and second light beams. The beam distance adjustment element includes a first incidence plane on which the first light beam is incident, a first exit plane that is parallel to the first incidence plane and from which the first light beam exits, a second incidence plane on which the second light beam is incident, and a second exit plane that is parallel to the second incidence plane and from which the second light beam exits. The first and second light beams intersect in the beam distance adjustment element.

Abstract: The present invention is directed to a method and system for providing phase modulated current to a semiconductor laser to control beam wavelength. A first current is received into a gain portion of the semiconductor laser and a second current is received into a DBR portion of the semiconductor laser. The second current is phase modulated based upon a required intensity value. An output beam is generated by the semiconductor laser based upon the received first current and the received second current.

Abstract: A laser apparatus in a hermetically sealed container and methods for hermetically sealing the laser. The laser apparatus comprising an external cavity laser and a modulator in a single hermetically sealed enclosure.

Abstract: The invention provides a method of reducing a time-averaged coherence of laser radiation for current-tunable lasers, and a laser apparatus realizing the method, by modulating the laser drive current using a modulation function optimized for obtaining a pre-determined time-averaged spectral profile of the laser radiation. In a preferred embodiment, the pre-determined time-averaged spectral profile has a substantially Gaussian shape. The method is described in reference to laser diodes.

Abstract: A method embodiment of the invention includes a scheme for trimming and compensation of a laser emitter in a fiber optic link. A laser emitter is provided. Also a reference optical power value is determined using data models of laser emitter performance generated by statistical analysis of sample population of lasers that are similar to the subject laser emitter. The performance of the subject laser is measured and qualified optical power levels for the subject laser emitter are determined using the reference operating power value and measured performance of the subject laser emitter. The driving current of the subject laser emitter is adjusted to compensate for changes in temperature until the optical power of the subject laser emitter obtains a desired qualified optical power level. Related methods of determining qualified optical power levels for a laser emitter in a fiber optic link are also disclosed.

Abstract: The two-dimensional photonic crystal surface emitting laser according to the present invention includes a number of main modified refractive index areas periodically provided in a two-dimensional photonic crystal and secondary structures each relatively located in a similar manner to each of the main modified refractive index areas. The location of the secondary structure is determined so that a main reflected light which is reflected by a main modified refractive index area and a secondary reflected light which is reflected by a secondary structure are weakened or intensified by interference.

Abstract: A laser is disclosed including a gain section having a distributed feedback grating imposed thereon. An absorption section is embedded in the gain section such that the first and second portions of the distributed feedback grating extend on either side of the electro-absorption section. A controller imposes a substantially DC bias signal on the first and second gain electrodes and imposes a modulation signal encoding digital data on the modulation electrode to generate a frequency modulated signal. In some embodiments, the first and second portions are biased above the lasing threshold and the absorption section is modulated below the lasing threshold to modulate loss in the absorption section.

Abstract: The field of the invention is that of integrated optical emission devices comprising a laser emission section and a section for modulating the optical power emitted by the laser, also known as ILM devices, the acronym standing for Integrated Laser Modulator. The invention is aimed at an ILM device comprising a laser section and a modulation section produced in a common structure of P.I.N type, the said structure successively comprising a substrate produced from n-doped semi-conductor material, a buried active zone, a p-doped vertical confinement layer and a semi-insulating lateral confinement layer, the part of the structure belonging to the laser section comprising a blocking layer produced from n-doped semi-conductor material disposed between the semi-insulating lateral confinement layer and the vertical confinement layer so as to reduce the leakage current existing between the said layers. The performance and the reliability of the final device is thus improved.

Abstract: A surface emitting laser (100a) includes an active layer (3) disposed on a semiconductor substrate (2a), and a pair of upper and lower electrodes (5,6) for injecting carriers into the active layer (3). The plane surface of the lower electrode (6) is shaped into a star so that injection of current into the active layer (3) from the lower electrode (6) is carried out with a high density at the center of the lower electrode (6) and with a low density at its periphery part. In the surface emitting laser (100a), the density distribution of the carriers injected into the active layer corresponds to the power distribution of light inside the active layer. Thereby, hole burning due to an increase in the current density in the region of the active layer corresponding to the peripheral part of the electrode is avoided, and the transverse mode stability during high output operation is significantly enhanced to improve high-output characteristic.

Abstract: A tunable pulsed laser source includes a seed source adapted to generate a seed signal and an optical circulator having a first port coupled to the seed source, a second port, and a third port. The tunable pulsed laser source also includes a modulator driver adapted to produce a shaped electrical waveform and an amplitude modulator coupled to the modulator driver and adapted to receive the shaped electrical waveform. The amplitude modulator is characterized by a first side coupled to the second port of the optical circulator and a second side. The tunable pulsed laser source further includes a first optical amplifier characterized by an input end and a reflective end. The input end is coupled to the second side of the amplitude modulator. Moreover, the tunable pulsed laser source includes a second optical amplifier coupled to the third port of the optical circulator.

Abstract: A method for producing stimulated emission of gamma radiation comprising: 1] providing at least first and second gamma-radiation sources, both sources being in recoil-free first-excited nuclear levels and the second source being in resonance with the first source and the gamma radiation from the first source being incident on the second source, 2] during the lifetime of its excited state, abruptly moving the first source through a distance equal to ½ the wavelength of the radiation emitted therefrom, thereby inducing a ?-phase-shift gamma radiation transparency in the second source whereby the ?-phase-shifted gamma radiation stimulates the excited nuclear resonant state of the second source to emit gamma radiation.

Abstract: A control system for controlling an optical modulator that intensity-modulates input light, the system includes an automatic bias control circuit configured to control an operating point of an optical modulator due to a bias voltage, including (i) a low-frequency signal superimposing unit configured to superimpose a low-frequency signal having a frequency lower than the frequency of a data signal on the data signal; (ii) a photoelectric converter configured to convert an optical signal intensity-modulated with an optical modulator into a voltage signal based on the data signal on which the low-frequency signal is superimposed; (iii) an error voltage detector configured to detect an error voltage corresponding to the low-frequency signal superimposed on the data signal from the voltage signal; and (iv) a bias controller configured to control a bias voltage for applying to the optical modulator based on the error voltage, and an automatic bias control stabilizing circuit configured to stabilize the automatic bi

Abstract: A light source unit and a spectrum analyzer are provided in which the influence of interference can be reduced under conditions where light is separated into spectral components. A spectrum analyzer 1 is equipped with a light source unit 2 for irradiating light onto sample A, a detector unit 3 for detecting the light reflected, scattered, or transmitted from the sample A, and a sample stage 4 on which a sample A is placed. A wide band light source 20 generates wide band light P1 such as supercontinuum light (SC light). Also, the light source unit 2 has an interference suppressing means for suppressing the interference of each wavelength component of the wide band light P1.

Abstract: A light source device includes a plurality of light emission sections disposed in parallel with an interval, wherein the interval for the light emission sections near each end portion in an array of the light emission sections is narrower than the interval near a center portion in the array.

Abstract: A system and method for controlling an optical transmitter. Proximate to startup of the optical transmitter, the laser bias to the optical transmitter is increased from a minimum to a setpoint according to a predefined function. After the laser bias setpoint is reached, the electrical modulation amplitude is increased from a minimum to a setpoint according to a predefined function. Proximate to shutdown of the optical transmitter, the electrical modulation amplitude is decreased from the setpoint to the minimum according to a predefined function. After the electrical modulation amplitude minimum is reached, the laser bias to the optical transmitter is decreased from a setpoint to a minimum according to a predefined function.

Abstract: A light source device generates irradiation light that is irradiated onto a predetermined face, the light source device including: a laser light source that emits laser light; a diffractive optical element that diffracts the laser light; a diffusion optical element that has an incidence face into which the laser light is incident and a light emission face from which the laser light from the incidence face is emitted, and that diffuses the laser light; and unit structures that are two-dimensionally arrayed on at least one of the incidence face and the light emission face of the diffusion optical element, and that cause the light which is perpendicularly incident into the diffusion optical element to refract at one time, and then emit this light toward the predetermined face.

Abstract: Provided are: an RF signal generator 110 which generates and outputs an RF signal having a signal waveform in which the potential of the signal changes to be alternately positive and negative with respect to a reference potential; a semiconductor laser 140 which receives, at its one end, a drive current which is based on the signal output from the RF signal generator 110; and a rectifier 150 which receives the drive current at its one end which has a polar directivity opposite to that of the one end of the semiconductor laser 140, with the other end of the semiconductor laser 140 and the other end of the rectifier 150 connected to a common potential.

Abstract: The present invention is directed to a method and system for providing a three-level current scheme to a semiconductor laser to control beam wavelength and laser temperature. A first current is received into a gain section of the semiconductor laser and at least one other current is received into a DBR and/or phase section of the semiconductor laser. This other current(s) is pulse-width modulated based upon a required temperature value. An output beam is generated by the semiconductor laser based upon the received first current and the received pulse-width modulated current(s).

Abstract: The invention relates to an integrated circuit for controlling a laser diode, comprising a signal input for receiving a data signal; a signal output for connection to the laser diode; a modulator for modulation of the data signal; a current infeed connected to the signal output for the supply of a bias current; a coupling capacitor between the output of the modulator and the signal output in order to form a high pass with the differential resistor of the laser diode. Preferably, the circuit also comprises an active compensation circuit with a low pass connected to the output of the modulator; and a circuit which is connected to the low pass for producing a signal which is inversely proportional to the low pass output voltage and which is added to the output signal or subtracted from the output signal. The low pass can be controlled by a circuit guiding the data signal.

Abstract: An apparatus and method for the production of polymeric films by a blown film process is disclosed. Polymeric films produced from crystallizable linear polymers are extruded through a die extruder, expanded by the injection of a gas inside the tubular film, cooled at the point of extrusion from the die, and further cooled at the point of maximal expansion or the frost line to produce a film having substantially enhanced optical characteristics.