Abstract: A laser control circuit comprises a temperature control circuit and a data processing circuit. The temperature control circuit adjusts the temperature of a laser diode by controlling a temperature regulator. The data processing circuit receives the output of a wavelength monitor. The data processing circuit first adjusts the, temperature of the laser diode to a temperature value previously associated with the target wavelength. Then the data processing circuit finely adjusts the temperature of the laser diode according to the output of the wavelength monitor. Because rough adjustment has been carried out, it is not necessary to change the wavelength significantly according to the output of the wavelength monitor. Therefore, the periodic wavelength dependence of the output of the wavelength monitor does not decrease the accuracy of the control.

Abstract: A laser apparatus and method that uses active thermalization of a reflective element to minimize losses and provide wavelength stability. The laser comprises first and second reflectors defining an external cavity, and a compensating member coupled to at least one of the reflectors and configured to thermally position one reflector with respect to the other reflector. The compensating member may be coupled directly to the first reflector and configured to position first reflector with respect to said second reflector. The thermal positioning may be carried out by a thermoelectric controller operatively coupled to the compensating member and configured to thermally adjust the compensating member by heating or cooling thereof. The laser apparatus may comprise a gain medium having first and second output facets and emitting a coherent beam from the first output facet along an optical path.

Abstract: A method of evaluating a tuneable laser and determining suitable hysteresis-free laser operation points. The laser includes two or more tuneable sections in which injected current can be varied, the tuneable sections including at least one reflector section and one phase section. The current injected through the reflector section is varied at different constant currents injected through respective remaining tuneable sections. The laser power output is measured at the front or the rear mirror of the laser while sweeping the reflector current in one direction and then in the opposite direction back to its starting value. The power difference with one and the same reflector current is calculated in the different sweep directions, and those combinations that give rise to a power difference that falls below a predetermined level are detected and stored as hysteresis-free current combinations.

Abstract: Passive thermal compensation for wavelength agile tuners provides high speed, accurate laser tuning over a wide range of wavelengths and temperatures. Thermal shims (104) and (106) closely coupled to agile tuning elements (100) perform wavelength offset corrections (73) in the rapidly changing thermal environment associated with high power pulse lasers. Sensor coupling mechanisms (114) compensate housing and tuning element for gain or band sensitivity thermal variations (62). Thermal injection from both wide temperature extreme ambient and tuned energy is accommodated. Improved thermal characteristics lead to a wider range of materials for higher performance and reduced metallurgical incompatibilities.

Abstract: An in-line broadband amplifier includes at least one input fiber and a WDM splitter coupled to the input fiber. The splitter splits an optical signal into at least a first wavelength and a second wavelength. A transition from a stop band to a pass band of the splitter occurs in 20 nm or less. A Raman amplifier and a rare-earth doped optical amplifier are coupled to the splitter. A WDM combiner is coupled to the Raman amplifier and the rare-earth doped optical amplifier. The WDM combiner combines an optical signal into at least a first wavelength and a second wavelength. A transition from a stop band to a pass band of the combiner occurs in 20 nm or less. An output fiber is coupled to the WDM combiner.

Abstract: A system for controlling the operating parameters of an optical source (1), such as a laser diode in a transmitter module for optical communications, includes:

Abstract: A digital burst mode laser control technique permits maintenance of a substantially constant laser output power for burst mode operation of a laser at lower duty cycles. The control technique may involve measurement of the output power level of a burst mode laser during a first burst frame, and comparison of the measured power level to a target power level. In addition, the control technique may further involve adjustment of a digital value based on the comparison, and conversion of the digital value to an analog value to control the output power level of the burst mode laser during a second burst frame. Hence, the control technique uses the output power level measured in a first burst frame to control the output power level of the burst mode laser during a subsequent burst frame.

Abstract: A method of maintaining desirable optical performance of optical emitters over temperature variations is disclosed. The optical performance of an optical emitter in terms of power, extinction ratio, jitter, mask margin and general fiber optic transmitter eye quality can be maintained by the present invention over a wide range of temperatures. Advantageously, the present invention enables the use of inexpensive optical emitters in optoelectronic transceivers and optoelectronic transmitters.

Abstract: Active element for a laser source and laser source comprising such an active element. According to the invention, the active element for a laser source comprises an elongate rod comprising a doped matrix capable of absorbing a pump beam in order to amplify laser radiation propagating longitudinally, at least one input face for the pump beam, a first reflection face for the pump beam which is inclined with respect to the longitudinal axis of the rod and at least one interacting second reflection face, at least one of the input face and second reflection face being equally inclined.

Abstract: A method of maintaining desirable optical performance of an optoelectronic apparatus at extreme temperatures is disclosed. At a first temperature, a first bias current at which the laser generates optical signals at a first level is determined. At a second temperature outside of a predefined range of the first temperature, a second bias current at which the laser generates optical signals at a second level is determined. If the second temperature is greater than the higher end-point temperature of the predefined range, the second predefined level is defined to be less than the first predefined level. If the second temperature is less than the lower end-point temperature of the predefined range, the second predefined range is defined to be greater than the first predefined level.

Abstract: A method of frequency and mode stabilising a tuneable laser, wherein one or more measurable magnitudes is/are measured, wherein the laser has been characterised with respect to a number of operation points, and wherein the values of the measurable magnitude or magnitudes are stored in a microprocessor or corresponding device. The invention is characterised by causing the values of one or more of the measurable magnitudes to be non-extreme values; storing the values of such non-extreme values as a quotient where the numerator is the derivative of a measurable magnitude &dgr;Y with respect to a control current &dgr;I to one laser section, and where the denominator is the derivative of another measurable magnitude &dgr;Z with respect to said control current &dgr;I; and using the stored values to control the laser to a desired operation point.

Abstract: In all-optical networks, high speed optical switching and routing becomes one of the most important issues for interconnecting the transport network layers. This invention describes novel polarization-independent high speed optical switches using a digital Faraday rotator, which can also be used for various other optical switching devices. The basic digital Faraday rotator device is composed of (a) a semi-hard or hard iron garnet based magneto-optic crystal having bi-stable magnetization states at zero external magnetic field. (b) a wire winding around the crystal for changing the magnetization states by pulsed current having both fast rise time and short duration. (c) a circuit generating the required current pulses with both polarities.

Abstract: The present invention relates generally to laser/detector packages, and particularly to laser/detector packages with components that increase the accuracy and ease of laser diode positioning. In particular, the laser/detector package of the present invention includes an attachment plate having a reference surface; a header post that is perpendicular to the reference surface when attached to the reference surface; sub-mount that houses a laser diode and abuts the reference surface or a spacer, which abuts the reference surface. By abutting the reference surface or the spacer, the laser diode attached to the sub-mount is easily and precisely positioned a proper distance from the reference surface. Additionally, preferred embodiments of the invention include a marking on the sub-mount that is parallel to the reference surface and a marking that is perpendicular to the reference surface on the spacer or sub-mount.

Abstract: An excimer or molecular fluorine laser system includes a laser tube filled with a gas mixture including fluorine and a buffer gas, and multiple electrodes within the laser tube connected with a pulsed discharge circuit for energizing the gas mixture. At least one of the electrodes is longer than 28 inches in length, preferably two main electrodes are each extended to greater than 28 inches in length. The laser system further includes a resonator including the laser tube for generating a pulsed laser beam having a desired energy. The laser system is configured such that an output beam would be emitted having an energy below the desired energy if each of the electrodes were 28 inches in length or less, and the laser system outputs a beam at the desired energy due to the length of the electrodes being extended to a length greater than 28 inches.

Abstract: A line narrowed laser system having a spatial filter to filter light at wavelengths greater and/or smaller than a desired range of wavelengths. The laser system is line narrowed with a line narrowing mechanism having a dispersive element which disperses laser light into wavelength dependent directions. By spatially filtering the resulting beam the bandwidth of the beam can be reduced substantially. There is also a reduction of beam energy as a result of the spatial filtering but this reduction is substantially less than some other known techniques for reducing bandwidths. A preferred spatial filter, for reducing the bandwidth of a line narrowed gas discharge laser, includes two cylindrical mirrors separated by a distance equal to their focal lengths with a slit aperture positioned at the common focal line.

Abstract: The quality of a multi-channel signal launched into an optical fiber may be degraded by active device distortion as well as non-linear fiber effects. Active device distortion in the form of clipping distortion and interferometric noise are reduced by a laser bias control circuit that does not require significant delay of the main RF signal. An information carrying signal, with periodic high amplitude peaks, drives the RF input of a laser as well as the input of a laser bias control circuit. The laser bias control circuit directly modulates the laser with a low frequency signal that is proportional to the frequency of occurrence and intensity of peaks in the information carrying signal that are likely to cause the laser to clip.

Abstract: An optical transmitter is equipped with a laser diode and a light detector provided on a packaging base, in which the light detector has a semiconductor substrate side arranged on a packaging base side, a semiconductor junction plane, a side surface which is roughly orthogonal to the semiconductor junction plane, and a facing surface which faces the side surface, wherein the facing surface is partially or completely inclined to reflect the output light from the laser diode incident from the side surface to the semiconductor junction plane of the light detector.

Abstract: First and second temperature control modules are disposed on a bottom surface inside a package. The first module has a prism, a wavelength filter, and a mount that holds a photodiode disposed thereon, thereby to form a wavelength monitoring section. The second module has an isolator, a lens holder that holds a lens, a laser mount on which a laser device is fixed, and a lens holder that holds a lens disposed thereon, thereby to form a laser emitter. An insulating plate is disposed between the first and second modules so as to prevent the occurrence of interference between the first and second modules.

Abstract: The pulsed laser control system comprises a plurality of controllers (2) through (6) for controlling devices (21) through (30) constituting the pulsed laser apparatus (1); parallel communication lines (P1) to (P4) for parallel connection of the plurality of controllers (2) through (6); an Ethernet (S) for serial connection of the plurality of controllers (2) through (6); parallel communication line (PP) for parallel connection between the external apparatus (10) and the main controller (2); and an Ethernet (SS) for serial connection between the external apparatus (10) and the main controller (2); wherein the parallel communication lines (P1) to (P4) and (PP) transmit signals for which realtime performance is required. With this construction, even if design changes are frequently made to a pulsed laser apparatus, the changes can be made easily and with little expansion space. Moreover, management of the devices constituting the pulsed laser apparatus can be easily performed.

Abstract: A laser array system is described. The system includes a plurality of lasers, a switching mechanism, a wavelength locking mechanism, and a laser parameter feedback control. Each laser provides a collimated beam having certain wavelength and power. The beam has at least two parts, first part of the two parts used for stabilization of the wavelength and power. The switching mechanism is configured to receive and sequentially select the first part of the collimated beam from the plurality of lasers. The wavelength locking mechanism is configured to monitor and measure a drift of the wavelength and power of a selected laser. The laser parameter feedback control is configured to adjust laser parameters of the selected laser.

Abstract: A backward laser beam radiated from a laser diode is received in a photo diode, and an intensity of a forward laser beam radiated from the laser diode is adjusted according to the intensity of the received backward laser beam. The forward laser beam radiated from the laser diode is collimated in a first lens held by a lens holder, and a most portion of the forward laser beam is output through a package window inclined with respect to an optical axis of the laser diode. The remaining portion of the forward laser beam is reflected on the package window as a reflected laser beam and is transmitted through the first lens to be converged in a narrow area placed above the laser diode. A light shielding plate extending in a plane orthogonal to the optical axis is arranged in a wide area including the narrow area and shields the photo diode from the reflected laser beam from. Therefore, the intensity of the forward laser beam radiated from the laser diode is correctly adjusted.

Abstract: The laser drive device of this invention includes a laser, first and second current sources, a current amplifier, and first and second transistors. When the first transistor is OFF, a first current from the first current source is supplied to the current amplifier, where the current is amplified to generate a laser current to be supplied to the laser. Thus, the laser is turned ON. During this time, the second transistor is ON, allowing a second current to flow from a power supply node into the second current source. When the first transistor is ON, the entire or part of the first current flows into the second current source through the first transistor. This reduces the current supplied to the current amplifier and thus the laser current, resulting in turning OFF the laser. During this time, the second transistor is OFF. The values of the first and second currents are determined by a set current value.

Abstract: A WDM optical transmission apparatus of the present invention comprises: a light source (1) for generating light whose wavelength is changed according to the temperature and a drive current; a temperature control section (4) for controlling the temperature of the light source so that a wavelength at the starting of emission of the light source is stabilized in an allowable range of optical output wavelength set in advance; a drive current control section (5) for controlling the drive current applied to the light source according to the allowable range of the optical output wavelength; a wavelength control section (3) for detecting a wavelength of light output from the light source and controlling the temperature of the light source based on the detection result, to lead the optical output wavelength into the vicinity of a predetermined target wavelength; and an operation control section (6) for controlling the start and stop of the control operation of each section at predetermined timing respectively corresp

Abstract: According to the present invention, there is provided a solid-state laser diode comprising:

Abstract: This invention relates to a light source (10) for producing a binary light signal of constant average power. The light source (10) includes a laser (12) and a current supply for supplying a current to the laser (12). The current has a slowly varying bias component (33) and a modulation component (35), each of which are independently controlled by the current supply so as to keep the average output power of the laser (12) constant when the temperature of the laser (12) changes during use. The current is controlled so as to keep the bias current just above the threshold current, the threshold current being inferred from previously obtained data values. An optical sensor is provided to monitor the average optical power output of the laser (12), and the modulation current is controlled by a feedback loop so as to keep the average optical output power constant.

Abstract: An auto laser power control circuit is provided which improves the response of the optical output level of a laser diode in accordance with variations in the operation mode.

Abstract: One of objects of the present invention is to provide a method of carrying out a laser annealing with sufficient uniformity and high productivity in a wide thickness range of a non-single crystal semiconductor film. According to one aspect of the present invention, a laser irradiation apparatus for carrying out irradiation while scanning a linear laser beam in a beam width direction is characterized in that the laser beam on an irradiation surface has a first energy density in a first beam width and a second energy density in a second beam width, and the second energy density is higher than the first energy density.

Abstract: A laser diode array assembly includes a laser diode array and a memory device integrally packaged with the array. The memory device includes operational information concerning the array. The memory device is accessible by a host external operating system which determines the manner in which the array is to be powered based on the operational information. The memory device may have the capability to be written to such that tie external operating system can record in the memory device significant events such as extreme operational conditions, operational faults, and the on-time or shot-count of the array. The assembly may include sensors to which the operating system is coupled. The assembly may further include a processing means to monitor the sensors and provide real-time updates to the external operating system such that laser diode array is continuously powered in an optimal manner.

Abstract: The invention particularly relates to a mixing apparatus using an eccentric phase plate, and an optical rangefinder using the mixing apparatus. In the optical rangefinder, an external distance measurement optical path leads light from the light source to a light receiving part passing through an article to be measured, an internal distance measurement optical path leads the light from the light source to the light receiving part not passing through the article to be measured, and processing means calculates the distance to the article to be measured from the difference between the distance value obtained by the external distance measurement optical path and the distance value obtained by the internal distance measurement optical path. In the mixing apparatus, driving means drives the phase plate.

Abstract: A laser processing method is presented for processing a circuit board including at least two layers, having a conductive layer with a plurality of holes disposed on a surface layer of insulating layer to be processed by applying laser beam to an insulating layer corresponding to holes of the conductive layer. In this laser processing method or apparatus, a circuit board is irradiated with a laser beam, and a reflected laser beam is detected, whereby the laser process of the insulating layer corresponding to an abnormal hole in the conductive layer is stopped, if the detected value of the reflected laser beam is an abnormal value out of a desired value. Also in this laser processing method or apparatus, the insulating layer corresponding to the hole is processed when the detected value of the reflected light conforms to the desired value.

Abstract: The gas laser oscillator of the invention comprises a discharge tube, a pair of electrodes disposed at both ends thereof, a direct-current high voltage power source for applying a direct-current high voltage in pulse form to the pair of electrodes, an output control device for controlling the direct-current high voltage power source, a fully reflective mirror provided at one end of the outside of the pair of electrodes, a partially reflective mirror disposed at the other end of the outside of the pair of electrodes, and an absorber disposed outside of the partially reflective mirror. In thus constituted gas laser oscillator, the output control device controls to apply a same direct-current voltage as during processing between the pair of electrodes also on standby while the absorber is closed.

Abstract: The optical signal produced by a modulated semiconductor laser is passed through a fiber grating optical discriminator to increase the modulation response of the device and decrease the output chirp for transmission through optical fiber. In one embodiment, a simple pulse source comprises a directly modulated single mode semiconductor laser and a fiber Bragg grating filter. A single-mode semiconductor laser, such as, a distributed feed-back laser is driven by the addition of a DC bias current and a sinusoidal current at the desired bit rate. The output of the laser is passed through a low pass or high pass fiber Bragg grating filter with a sharp edge to produce nearly transform limited pulses. Stabilization of a laser apparatus is included.

Abstract: The gas laser oscillator of the invention comprises a discharge tube, a pair of electrodes disposed at both ends thereof, a direct-current high voltage power source for applying a direct-current high voltage in pulse form to the pair of electrodes, an output control device for controlling the direct-current high voltage power source, a fully reflective mirror provided at one end of the outside of the pair of electrodes, a partially reflective mirror disposed at other end of the outside of the pair of electrodes, and an absorber disposed outside of the partially reflective mirror. In thus constituted gag laser oscillator, the output control device controls to apply a same direct-current voltage as during processing between the pair of electrodes also on standby while the absorber is closed.

Abstract: A temperature compensation apparatus for controlling an output power of a laser diode according to a temperature variation of the laser diode, and a method therefor. An error voltage between a voltage corresponding to the output power of the laser diode and a reference voltage is generated. The error voltage is output as a control voltage corrected based on the output power and is applied to the laser diode. When the level of the error voltage overflows or underflows in a first up/down counter, the control voltage based on the luminous efficiency of the laser diode is output by applying the corrected control voltage to the laser diode while interlocking the first up/down counter with a second up/down counter. Accordingly, it is possible to stabilize the luminous efficiency and reduce control error of the laser diode.

Abstract: A light generating apparatus includes: a submount; a semiconductor laser chip mounted on the submount; a substrate which is mounted on the submount and includes an optical waveguide; and a substance having a predetermined thickness which is disposed between the semiconductor laser chip and the substrate. In an oscillation wavelength stabilizing apparatus for a light source, the light source is a semiconductor laser which includes: an active region for providing gain; and a distributed Bragg reflection (DBR) region for controlling an oscillation wavelength.

Abstract: A solid state laser includes a solid state laser crystal, a pumping source for pumping the laser crystal, a resonator, an enclosed casing which is filled with gas and in which the resonator is contained, and a temperature controller which keeps the resonator at a predetermined temperature. The ratio of the optical length of the gas layer in the resonator to the oscillation wavelength of the solid state laser is set to be not larger than 13600.

Abstract: A laser generating apparatus has a plurality of laser resonators and control loops for generating frequency locking signals independently for the respective laser resonators. A control signal generation circuit is provided so as to be common to the control loops. Control signals generated by the control signal generation circuit by frequency division are supplied to the respective control loops, whereby the phases of the laser resonators are locked to each other.

Abstract: An automatic gain control circuit in the feedback path for a laser wavelength control circuit is described herein. This gain control circuit automatically adjusts the amplification of the analog signals output from a photodetector array, where the array detects a fringe pattern created by a laser beam. Another feature of the preferred embodiment feedback circuit is the automatic setting of a DC offset voltage that compensates for errors in the feedback path and enables an accurate determination of a dark level signal in the fringe pattern signal. This dark level signal provides a reference for measuring the magnitude of the fringe pattern signal. Varying photodetector outputs may now be more accurately measured. The preferred embodiment feedback circuit also employs a very fast amplifier anti-saturation circuit using LED's connected in a clamp circuit.

Abstract: A laser diode array assembly includes a laser diode array and a memory device integrally packaged with the array. The memory device includes operational information concerning the array. The memory device is accessible by a host external operating system which determines the manner in which the array is to be powered based on the operational information. The memory device may have the capability to be written to such that the external operating system can record in the memory device significant events such as extreme operational conditions, operational faults, and the on-time or shot-count of the array. The assembly may include sensors to which the operating system is coupled. The assembly may further include a processing means to monitor the sensors and provide real-time updates to the external operating system such that laser diode array is continuously powered in an optimal manner.

Abstract: A self-mixing sensor usable for remotely measuring speed, vibrations, range, and length is provided in a manner making the device practical for economic implementation while retaining accuracy. In one embodiment, the device is configured to avoid mode hopping, such as by providing for relatively high loss for all modes other than the desired mode. Preferably this is accomplished by utilizing laser types that have a high degree of side mode supression, such as DFB lasers or through active or passive control of the amount of light permitted to reenter the laser.

Abstract: An optical transmitter includes a plurality of optical wavelength stability control apparatuses, each of which is capable of compensating for a wavelength drift by varying a laser diode drive current. Each of the optical wavelength stability control apparatuses detects a laser diode drive current, which is controlled by an auto power control circuit, by using a laser diode drive current detector. The laser diode drive current is normalized by a laser diode drive current increase/decrease normalization unit. A laser diode temperature control target value is generated at a compensated reference voltage generator, in response to the normalized laser diode drive current, to control a current value applied to a thermoelectric cooler so that an output value of a temperature monitor circuit approaches a predetermined laser diode temperature control target value.

Abstract: An optical transmitter (200) in a cable television system (100) includes an uncooled laser diode (250) and a thermal compensation circuit (FIG. 2). The thermal compensation circuit includes a voltage controlled attenuator (220) located between the transmitter input (205), at which an electrical information signal is received, and the laser diode (250). The thermal compensation circuit also includes a thermistor (230) that is situated physically near the laser diode (250) and that is characterized by a resistance that varies with temperature. The thermistor (230) is coupled to a controller (225) for sensing thermistor resistance changes, which are indicative of changes in the laser diode temperature, and for selectively controlling the attenuator (220) to attenuate the level of the electrical information signal.

Abstract: A laser chamber with a circuitous gas return path dissipates shock waves. In one embodiment, the laser chamber includes a heat exchanger with a large surface area that defines an aerodynamic passage through which gas circulates in the laser chamber. The passage through which the gas circulates directs shock waves away from the discharge region so that the shock waves may dissipate elsewhere in the laser chamber. In addition, the large surface area of the heat exchanger efficiently cools the thermally energetic gas within the laser chamber. In another embodiment, ancillary chambers that are fluidically coupled to the main laser chamber are provided to permit shock waves to be directed away from the discharge area and to be dissipated within the ancillary chambers. Openings to the ancillary chambers are positioned such that shock waves generated by the electrode structure of the laser chamber may propagate directly into the ancillary chamber, where the shock waves then dissipate.

Abstract: A first embodiment of an adjustment circuit for a laser diode output power compensator includes a feedback circuit for adjusting the laser diode output power compensator so that the output power of the laser diode is substantially constant. The feedback circuit includes a photodiode for measuring the output power of a VCSEL diode. The signal from the photodiode is coupled to a first amplifier. The difference between the signal from the photodiode and a first reference value is amplified and coupled through electronic switches to selectively charge one of multiple capacitors. The multiple capacitors are each coupled to one of a drive current source, a compensation current source, and a voltage controlled resistor, each of which are voltage controlled. A second amplifier is used for amplifying the difference between the signal from the photodiode and a second reference value to charge a capacitor coupled to a voltage controlled bias current source.

Abstract: A solid state laser has an elongate slab of lasing material having a rectangular cross section with the lower face of the slab contacting a slab mount which is of a high thermal conductivity material. Energy to drive the lasing medium is provided by a flash lamp. Upper and lower faces of the slab are polished to an optically smooth finish so that light is able to propagate in a generally axial direction through the slab. Side faces of the slab are polished and then re-roughened to provide a finish with a surface damage zone comparable in depth to the wavelength of the lasing emission. For a lasing wavelength of one micrometer, the depth of surface damage is in the region of one micrometer.

Abstract: A device for detecting failures in a laser transmitting passage includes an inner tube (80) made from an optical hollow waveguide and having a first space (122) through which laser is transported, an outer tube (78) surrounding and extending along the inner tube, and a detector which recognizes a first condition in which the first space is fluidly disconnected from the second space and a second condition in which the first space is fluidly connected to the second space. The first and second conditions can be determined from a pressure, flow rate, gas concentration, ingredient of gas, or temperature in first or second space.

Abstract: An automatic personal computer-based, rapid calibration system for tunable, narrowband lasers is achieved, detecting the LIF (Laser Induced Fluorescence) spectrum of a suitable known medium in a reference cell, which is also stored as a database in the PC to compute a functional relationship between the wavelength-shifting actuator in the laser and the emitted laser wavelength. The PC is either connected to the LIF spectrum-detecting circuit and the laser interface. Substances (media) used for reference have to exhibit at least two distinct electronic absorption lines within the tunability range of the laser. By comparing the measured and the stored LIF spectrum of the reference medium, the spectral properties of the laser are calculated automatically.

Abstract: Automatic power control of a semiconductor laser (12, 72) is achieved by monitoring the spontaneous lateral emissions from the semiconductor laser and adjusting the drive signal to the laser based on the detected emissions. A lateral detector (13, 73) generates a photocurrent from the spontaneous emissions. The detector signal (Ilat) is compared to a reference signal (Iref) and the difference is applied to the drive signal (Ilas) to alter or control the laser output. The magnitudes of the reference signal source and the drive signal source are determined and set based on the desired optical output power of the semiconductor laser measured at a series of temperatures.

Abstract: A laser power control system (150; 150') having a first pulse stretch capability, as may be used in a rapid prototyping system (100), is disclosed. According to one disclosed embodiment, a one-shot multivibrator (156) generates a pulse responsive to a gate signal (LON/LOFF.sub.--) indicating that the laser (110) is to be turned on. The pulse, which is of a selected duration suitable for achieving population inversion, is applied to the laser (110); upon the end of this pulse, pulse-width-modulation (PWM) control of the laser begins. According to another disclosed embodiment, a first pulse stretch store (166) retains a digital value corresponding to the duration by which the first PWM pulse is to be lengthened; adders (176; 178) add this digital value to the parameters indicated by the desired laser power signal (DLP) to ensure population inversion and laser output of the laser (110) in the first pulse.

Abstract: A laser diode array assembly includes a laser diode array and a memory device integrally packaged with the array. The memory device includes operational information concerning the array. The memory device is accessible by a host external operating system which determines the manner in which the array is to be powered based on the operational information. The memory device may have the capability to be written to such that the external operating system can record in the memory device significant events such as extreme operational conditions, operational faults, and the on-time or shot-count of the array. The assembly may include sensors to which the operating system is coupled. The assembly may further include a processing means to monitor the sensors and provide real-time updates to the external operating system such that laser diode array is continuously powered in an optimal manner.