Abstract: An optical communication system includes an optical module and a host. The optical module has a fiber connector and a laser condition pin, wherein the fiber connector is configured to connect to a laser output of an external laser source. The optical module is configured to set an output of the laser condition pin to have a first value when detecting a laser beam through the fiber connector. The host is connected to the laser condition pin and has a control connector, wherein the control connector is configured to connect to the external laser source. The host is configured to output a release signal through the control connector when detecting the first value on the laser condition pin, wherein the release signal changes the laser output from outputting a laser beam having a first power to outputting a laser beam having a second power higher than the first power.

Abstract: A light emission apparatus includes a transistor comprising a control terminal, a first channel terminal, and a second channel terminal, wherein the control terminal is configured to receive a modulation signal, the first channel terminal is configured to generate a driving signal according to the modulation signal, and the second channel terminal is coupled to a fixed voltage; and a load comprising: a first terminal; a second terminal, wherein the first terminal is coupled to the first channel terminal of the transistor and the second terminal is coupled to the fixed voltage; a laser diode configured to emit a light according to the driving signal; and a first capacitor coupled to the laser diode, configured to isolate a DC current on the first terminal of the transistor.

Abstract: Various implementations of the invention compensate for “phase wandering” in tunable laser sources. Phase wandering may negatively impact a performance of a lidar system that employ such laser sources, typically by reducing a coherence length/range of the lidar system, an effective bandwidth of the lidar system, a sensitivity of the lidar system, etc. Some implementations of the invention compensate for phase wandering near the laser source and before the output of the laser is directed toward a target. Some implementations of the invention compensate for phase wandering in the target signal (i.e., the output of the laser that is incident on and reflected back from the target). Some implementations of the invention compensate for phase wandering at the laser source and in the target signal.

Abstract: Noise caused by switching is reduced using a simple configuration in a circuit amplifying a pulse signal using a switching amplifier. A control data output section outputs control data that instructs that a pulse width of each of a pair of pulse signals be modulated. A data replacement section replaces the control data with data for replacement different from the control data in the case where the control data is output that instructs that the modulation leading to approximately a same pulse width for the pair of pulse signals be performed. A pulse width modulation circuit performs the modulation on each of the pair of pulse signals in accordance with the data for replacement. A pair of switching amplifiers amplify the pair of pulse signals that have been subjected to the modulation.

Abstract: Typically, quantum systems are very sensitive to environmental fluctuations, and diagnosing errors via measurements causes unavoidable perturbations. Here, an in situ frequency-locking technique monitors and corrects frequency variations in single-photon sources based on resonators. By using the classical laser fields used for photon generation as probes to diagnose variations in the resonator frequency, the system applies feedback control to correct photon frequency errors in parallel to the optical quantum computation without disturbing the physical qubit. Our technique can be implemented on a silicon photonic device and with sub 1 pm frequency stabilization in the presence of applied environmental noise, corresponding to a fractional frequency drift of <1% of a photon linewidth. These methods can be used for feedback-controlled quantum state engineering.

Abstract: Systems and methods for calibrating, operating, and setting the magnitude of the power of light provided by a laser diode in a conducted electrical weapon (“CEW”). The light of the laser diode assists in targeting by providing a visible indication of the projected point of impact of the tethered electrode of the CEW. The calibration process enables laser diode of a CEW to operate within regional guidelines of the maximum output power of light permitted by a laser. The method further permits the magnitude of the power of the light provided by a laser diode to be set and operated in changing environmental conditions in the field.

Abstract: A coolant supply system includes a coolant tank for accumulating coolant generated by using deionized water, a coolant supply passage for supplying the coolant in the coolant tank to the laser processing head, an electric conductivity meter for measuring an electric conductivity of the coolant to be supplied to the laser processing head, a drainage passage capable of draining the coolant from the coolant tank, an electromagnetic valve provided on the drainage passage, and a controller that controls open/close operations of the electromagnetic valve. The controller turns the electromagnetic valve from a closed state into an open state to drain the coolant in the coolant tank through the drainage passage when a measured value of the electric conductivity meter exceeds over a preset upper limit value.

Abstract: A driver circuit for at least one light-emitting optoelectronic component includes a control circuit having a capacitor and a control switch, wherein the control switch electrically connects to the component such that the component is supplied with current by the capacitor as a function of a switching state of the control switch, and a charging circuit having at least a first charging switch, a bias resistor and a buffer capacitor, wherein the charging circuit electrically connects to the capacitor and is configured to charge the capacitor through the bias resistor, and the buffer capacitor is linked to a connecting line between the bias resistor and the capacitor.

Abstract: In a first embodiment, an external cavity tunable laser, comprising a silicon photonics circuit comprising one or more resonators having one or more p-i-n junctions; wherein a voltage is applied to one or more of the p-i-n junctions. In a second embodiment, a method of operating an external cavity tunable laser, comprising sweeping out free-carriers from a resonator of the tunable laser by applying a voltage to a p-i-n junction of a waveguide of the resonator.

Abstract: An optical transmission module includes: a bias current drive circuit to drive a bias current of a light-emitting element, on a basis of an input bias current setting value; a modulation current drive circuit to drive a modulation current of the light-emitting element, on a basis of an input modulation current setting value; a light-receiving element to measure an optical output power of the light-emitting element; a determiner to determine whether a difference between a target value of the optical output power and the optical output power measured by the light-receiving element is equal to or more than a threshold; and a controller configured to perform a correction control to the bias current drive circuit so that the bias current is reduced in accordance with the difference, when it is determined that the difference is equal to or more than the threshold by the determiner.

Abstract: A system for controlling an optical intensity and modulation of an optical data transmitter which includes current driver circuitry configured to provide a drive current to a laser diode wherein said current comprises a fixed component and a modulated component, said modulated component having a magnitude related to an input data stream. The monitor circuitry contains a photodiode and a first transimpedance amplifier coupled to said photodiode, said monitor circuitry configured to provide an output signal related to an optical intensity of said laser diode. The system further includes replica monitor circuitry containing a replica capacitor with a replica capacitance and a second transimpedance amplifier configured to be substantially identical in construction to said first transimpedance amplifier, said second transimpedance amplifier coupled to said replica capacitor.

Abstract: A laser component includes a housing, a laser chip arranged in the housing, and a conversion element for radiation conversion arranged in the housing wherein the conversion element is irradiatable with laser radiation of the laser chip. A method of producing such a laser component includes providing component parts of the laser component including a laser chip, a conversion element for radiation conversion and housing parts, and assembling the component parts of the laser component such that a housing is provided within which the laser chip and the conversion element are arranged, wherein the conversion element is irradiatable with laser radiation of the laser chip.

Abstract: A ripple pre-amplification based fully integrated LDO pertains to the technical field of power management. The positive input terminal of a transconductance amplifier is connected to a reference voltage Vref, and the negative input terminal of the transconductance amplifier is connected to the feedback voltage Vfb. The output terminal of the transconductance amplifier is connected to the negative input terminal of a transimpedance amplifier and the negative input terminal of an error amplifier. The positive input terminal of the transimpedance amplifier is connected to the ground GND, and the output terminal of the transimpedance amplifier is connected to the positive input terminal of the error amplifier. The gate terminal of the power transistor MP is connected to the output terminal of the error amplifier, the source terminal of the power transistor MP is connected to an input voltage VIN, and the drain terminal of the power transistor MP is grounded.

Abstract: The method of phase modulating a carrier wave involves creating a set of signals sh(t) constituted by a carrier wave of frequency fC and of phase ?(t)=h?0(t) that is modulated in time t in such a manner that sh(t)=cos(2?fCt+h?0(t)), where h is an integer and where ?0(t)=2 arctan((t?t0)/w0). The modulation corresponds to a single phase pulse centered on a time t0 of characteristic duration w0 that is positive, and incrementing the phase of the signal sh(t) by the quantity h2?, in such a manner as to generate a single sideband frequency spectrum directly. The carrier wave may be of electromagnetic type or of acoustic type. The method applies in particular to transporting binary information by single sideband phase coding, to generating single sideband orthogonal signals, to detecting single sideband phase coded multiple-level digital signals, to transmitting single sideband phase coded binary signals in-phase and out-of-phase, and to single sideband combined amplitude-and-phase modulation.

Abstract: The invention describes a laser printing system (100) for illuminating an object (70) in a working plane (80). The object (70) moves relative to a print head (50) of the laser printing system (100). The print head (50) comprises a total number of laser modules (150), each laser module (150) comprises at least one laser array (110) of lasers (115). At least two of the laser modules (150) share an electrical power supply (20). The laser printing system (100) further comprises a controller (10) being adapted such that at maximum processing speed of the print head (50) only a predefined number of laser modules (150) can be driven at nominal electrical power, wherein the predefined number of laser modules (150) is smaller than the total number of laser modules. The invention further relates to a corresponding method of laser printing.

Abstract: System, including methods and apparatus, for optical detection. The system may comprise a light source to generate a beam of light, an optical element, and a detector. The optical element may include a light guide having a shaft and a tip, with the tip forming a beveled end of the light guide. The optical element may extend into the beam, such that the tip and at least a portion of the shaft are located inside the beam, and a window of the optical element is located outside the beam. Light of the beam incident on the tip may be transmitted longitudinally through the light guide and out the window, while light of the beam incident on the shaft may be transmitted transversely through the shaft and remains in the beam downstream. The detector may be configured to detect light received from the window.

Abstract: An apparatus includes an illumination source configured to emit light when driven with a current greater than a threshold current and driver circuitry configured to drive the illumination source with a controllable current. The driver circuit controlled by at least a first input value. At least one illumination detector is configured to detect light emitted by the illumination source and monitor circuitry is configured to receive an output from the illumination detector and provide the first input value.

Abstract: An optical signal module including a driver and an optical signal module. The driver includes a differential pair configured to receive and process an input signal to create a drive signal. A modulation current source provides a modulation current to the differential pair. One or more termination resistors connected to the differential pair for impedance matching. A first switch, responsive to a first control signal, maintains charge on a charge storage device. The optical signal module includes an optical signal generator arranged between a supply voltage node and a bias current node. The optical signal generator receives the drive signal and generates an optical signal representing the input signal. A second switch is between a supply voltage node the bias current node. The second switch, responsive to second control signal, selectively establishes a short between the supply voltage node the bias current node.

Abstract: A method and apparatus for controlling a dose of radiation generated by a laser light source is disclosed. In one embodiment, a dose controller receives measurements of the deviation of output energy from an expected output energy, or “energy sigma,” and the standard deviation of the error in the dose received by the item being processed from the desired dose. The ratio of the energy sigma to the standard deviation of dose error is calculated, and the laser controller adjusts the controller gain based upon the calculated ratio so as to adjust the voltage determined by the controller, and consequently the output energy and thus the dose to the item. This is an improvement over the prior art, in which the controller gain is adjusted based upon sending a voltage dither to the laser and correlating it to its response in energy at only one frequency.

Abstract: A dental laser treatment system includes a treatment laser beam and a pilot (e.g., aiming/marking) laser beam sharing a collinear beam path, where the beam path is guided by a guidance system through a handpiece/main chamber assembly having a beam exit. A laser beam presence detector is removably affixed to or within the handpiece/main chamber assembly. The laser beam presence detector provides feedback to a computer which can control actuation of the treatment laser beam and the pilot laser beam, and the beam guidance system. The computer performs a search for determining the center location of the beam exit based on the feedback and controls the beam guidance system to guide the beam path approximately to the center of the beam exit, thereby providing automatic alignment of the laser beam with the beam exit or an optional hollow waveguide.

Abstract: An optical signal generation section and a transmitter control section are provided. The optical signal generation section includes a light source, a temperature adjuster that adjusts a temperature of the light source, and a light amplifier that amplifies light generated by the light source and generates burst signals. The transmitter control section includes a temperature change suppresser that sends a temperature suppression signal to the temperature adjuster, the temperature suppression signal reporting a temperature suppression amount that is to suppress a temperature change of the light source caused by burst signal generation at the light amplifier. The temperature adjuster receives the temperature suppression signal at least a duration that the temperature adjuster requires for temperature adjustment before a timing at which the light amplifier is to generate a burst signal.

Abstract: A laser system having an automatic diagnosis function enabling a plurality of laser diodes to be diagnosed for faults in a short time. The laser system includes a judging part judging the presence of a fault or deterioration of a component of the laser system. The judging part is configured to judge the presence of a fault or deterioration of a component of the laser system based on the results of detection of a first photodetection part and second photodetection part when successively driving a plurality of laser diode module groups included in an individual laser oscillation unit so that the mutual drive times do not overlap simultaneously for at least two laser oscillation units among a plurality of laser oscillation units.

Abstract: A laser apparatus includes laser diode module groups (LDMGs) and power supply units and provides a laser light source by collecting laser beam from the LDMGs, and comprises: a driving current supply circuit network for injecting the driving currents into the respective LDMGs, independently; a control unit which controls the driving currents independently; a first recording unit in which are recorded data representing a relationship between the driving current and optical output power, and data representing a relationship between the driving current and drive voltage; and a first calculating unit which calculates the driving currents to be allocated to the LDMGs so as to achieve maximum electrical to optical conversion efficiency, wherein the control unit allocates the driving currents to the LDMGs in accordance with the results calculated by the first calculating unit so that the LDMGs as a whole can achieve maximum electrical to optical conversion efficiency under conditions.

Abstract: An optical transmitter driver is disclosed to drive a load with a drive signal responsive to a first and second input signal. The differential pair includes a first path having a first resistor connected to a first voltage supply and to a first transistor that receives the first input signal. A second path includes a second resistor connected to a second voltage supply and a second transistor. The first voltage supply is less than the second voltage supply. The second transistor has an input configured to receive the second input signal and the first and second input signals define a differential signal. Also part of this embodiment is a load connection node that presents the drive signal to the load. The first voltage supply is less than the second voltage supply. In one configuration cross coupled capacitor are connect between each input and the first path and second path.

Abstract: Light with a short pulse width is emitted using a simple structure. A light source 101, a differentiation circuit 102, and a switch 103 are connected in series. When the switch 103 is switched on, inrush current flows in a capacitor 102b forming the differentiation circuit 102, and accordingly the light source 101 is supplied with electric current and thereby emits light. When the capacitor 102b is charged, electric current flows in a resistor 102a, and voltage drops at the resistor 102a. Then, the voltage applied to the light source 101 is decreased, whereby the light source 101 stops emitting light. The values of the resistor 102a and the capacitor 102b are adjusted so that the above phenomenon occurs.

Abstract: A system for an extreme ultraviolet (EUV) light source includes an optical amplifier including a gain medium positioned on a beam path, the optical amplifier configured to receive a light beam at an input and to emit an output light beam for an EUV light source at an output; a feedback system that measures a property of the output light beam and produces a feedback signal based on the measured property; and an adaptive optic positioned in the beam path and configured to receive the feedback signal and to adjust a property of the output light beam in response to the feedback signal.

Abstract: An image forming apparatus, including: a laser light source supplied with a bias current and a superimposed current to emit laser light; a splitting unit configured to split the laser light into first and second laser lights; a photoelectric conversion unit configured to output a voltage corresponding to a light intensity of the second laser light; a voltage holding unit configured to hold a voltage output from the photoelectric conversion unit with not the superimposed current but the bias current being supplied to the laser light source; a voltage conversion unit configured to remove the voltage held by the voltage holding unit from the voltage from the photoelectric conversion unit which receives the second laser light; and a current control unit configured to control, based on a voltage from the voltage conversion unit, a value of the superimposed current supplied to the laser light source based on image data.

Abstract: A controller may be configured to: (i) predict based on an electronic transformer secondary signal an estimated occurrence of a high-resistance state of a trailing-edge dimmer coupled to a primary winding of an electronic transformer, wherein the high-resistance state occurs when the trailing-edge dimmer begins phase-cutting an alternating current voltage signal; (ii) operate a power converter in a trailing-edge exposure mode for a first period of time immediately prior to the estimated occurrence of the high-resistance state, such that the power converter is enabled to transfer energy from the secondary winding to the load during the trailing-edge exposure mode; and (iii) operate the power converter in a power mode for a second period of time prior to and non-contiguous with the first period of time, such that the power converter is enabled to transfer energy from the secondary winding to the load during the power mode.

Abstract: An arbitrary waveform generator modifies the input signal to a laser diode driver circuit in order to reduce the overshoot/undershoot and provide a “flat-top” signal to the laser diode driver circuit. The input signal is modified based on the original received signal and the feedback from the laser diode by measuring the actual current flowing in the laser diode after the original signal is applied to the laser diode.

Abstract: An electronic circuit contains a flip-flop, a switch, a photodiode and a mode-locked laser. The mode-locked laser generates light pulses, which generate a photocurrent in the photodiode the switch transfers the photocurrent to one of two inputs of the flip-flop. The flip-flop outputs its status to at least one output.

Abstract: In master oscillator-power amplifier (MOPA) systems for generating laser light, a fluorine concentration in each of the master oscillator and power amplifier chambers is maintained. While sensors at the chambers can measure certain values of some variables, the sensors do not directly measure fluorine concentration. As a further complication, the values received from the sensors are known to be affected by various specified variables. To estimate the effect on the received values, an RLS algorithm and covariance matrix are used. To ensure that the RLS algorithm is responsive to recent changes in a specified variable, portions of the covariance matrix are reset to more quickly and more heavily weight the more recent values.

Abstract: A light source system that generates stable optical power over time and temperature in which a feedback control circuit is operative to receive a temperature signal and a sample signal and in response thereto generate a control signal to a driver circuit to maintain a power level of the light output substantially constant over an operative temperature range defined by Tmin and Tmax.

Abstract: A system and method that can be employed to lock and scan the output of a laser cavity (2) is described. The system and method involves the use of a signal generator for generating an error signal between an output of the laser cavity (28) and the transmission (28) of the laser through a tunable external reference cavity (3). A dual piezo-actuated mirror (6b) permits processing of the error signal (26) with separate signal processing circuits (29a, 29b) used to provide an electrical feedback signal to the two piezo electric crystals (22, 23b). When incorporated within a laser cavity the described system and methodology can be used to lock and scan the output of the laser cavity while providing the laser output with a reduced linewidth.

Abstract: Provided is a recording apparatus including a self-excited oscillation semiconductor laser that has a double quantum well separate confinement heterostructure and includes a saturable absorber section to which a negative bias voltage is applied and a gain section into which a gain current is injected, an optical separation unit, an objective lens, a light reception element, a pulse detection unit, a reference signal generation unit, a phase comparison unit, a recording signal generation unit, and a control unit.

Abstract: The invention relates to solid state light source, a use of a driver circuit for driving a light emitting element (150) of a solid state light source, a method for driving a light emitting element (150) of a solid state light source and a corresponding computer program. The invention provides that for a large amount of an AC period the light emitting element (150) is directly supplied with the AC input directly forwarded by the driver circuit, wherein nevertheless it is prevented that power exceeding a desired level reaches the light emitting element (150). The invention is aimed at a realization with simplified components and/or reduced costs in comparison to known techniques.

Abstract: A laser driver circuit having a differential circuit and an output circuit includes a control circuit receiving a regulated supply voltage that also supplies the differential circuit as an input signal. The control circuit generates a feedback voltage across a first resistor to cause a first current to flow in the first resistor having a current value equal or proportional to the modulation current value. The laser driver circuit includes an operational amplifier receiving the feedback voltage and a reference voltage indicative of a desired modulation current value and to generate the regulated supply voltage. The control circuit and the operational amplifier form a feedback control loop to adjust the regulated supply voltage to regulate the feedback voltage to be equal to the reference voltage, thereby regulating the modulation current value to the desired modulation current value.

Abstract: A light emission apparatus includes a detection unit, a first drive unit, and a second drive unit. The detection unit detects the state of a detection element. The first drive unit controls the light amount of a light beam to be emitted by a first light emitting element based on the state of the detection element detected by the detection unit. The second drive unit controls the light amount of a light beam to be emitted by a second light emitting element based on the state of the detection element detected by the detection unit.

Abstract: A method of optical signal amplification. Incident photons are received at a photodetector including a doped semiconductor biased by a power source. The photons generate a change in a reflective property, refractive index, or electrical conductivity of the doped semiconductor. For the change in reflective property or refractive index, a first optical signal is reflected off the photodetector to provide a reflected beam, or the photodetector includes a reverse biased semiconductor junction including the doped semiconductor within a laser resonator including a laser medium, wherein a second optical signal is emitted. For the change in electrical conductivity the photodetector includes a reversed biased semiconductor junction that is within an electrical circuit along with an electrically driven light emitting device, where a drive current provided to the light emitting device increases as the electrical conductivity of the photodetector decreases, and the light emitting device emits a third optical signal.

Abstract: There provided is a semiconductor laser control device which including plural light sources that are configured with eight or more semiconductor laser elements, a one detecting section that detects a light power of the light sources, a light power control unit that compares a signal according to a light power detected by the detecting section with a control signal corresponding to a predetermined light power to control a current supplied to the light sources, and a voltage clamp circuit that functions as an overvoltage preventing means for the detecting section when turning on each of the light sources to perform light power control.

Abstract: In a VCSEL driver for automatic bias control and automatic modulation control, the VCSEL driver includes: a feedback module configured to receive an output of a VCSEL to provide a bias signal through a feedback loop; an automatic bias control block configured to adjust a bias current by switching on or off a plurality of power sources, which are connected in parallel with each other; an automatic modulation control block configured to connect in parallel a plurality of bias transistors that are connected to each of the plurality of power sources, and to adjust modulation current by switching each of the plurality of bias transistors on or off; and a main driver configured to provide the VCSEL with a drive current including the bias current and the modulation current, which are adjusted by control of each of the control blocks.

Abstract: Methods and circuits for providing a minimum driving voltage to a current-driven load (such as a laser diode) are disclosed. The circuit and methods may be useful for efficiently providing a bias and/or driving current to the current-driven load with minimal energy loss. The circuit generally comprises (1) a driver or voltage source configured to provide the bias and/or driving current to the current-driven load, (2) a sense circuit configured to (i) sense the bias and/or driving current and (ii) convert the bias and/or driving current to a first voltage, and (3) a comparator configured to (i) receive the first voltage and first and second reference voltages and (ii) provide a feedback/error signal to the driver or voltage source, the feedback/error signal configured to maintain or adjust the bias and/or driving current at or towards a target value.

Abstract: A light source system for delivery of light including a light source having an output arranged to emit light in an output path, the output path including an unguided section and an at least partially transmissive optical component wherein the optical component provides at least one residual reflection when the system is in use and a detector system is arranged to detect said residual reflection. The detector is in one embodiment arranged to produce at least one feedback response arranged to stabilize the optical output of the light source system. Hereby a feedback may be implemented with little or no reduction of performance.

Abstract: A quantum cascade laser (QCL) may include a QCL crystal having an emitting facet, and an active region adjacent the emitting facet, the emitting facet for providing an electromagnetic beam. The QCL may include an optical cavity comprising a mirror being external to the QCL crystal, and for redirecting the electromagnetic beam into the active region of the QCL crystal to provide optical feedback, and a driver circuit for driving the QCL crystal with a constant current. The QCL may include a controller coupled to the optical cavity and for dynamically and autonomously aligning the optical cavity based upon an error signal from the QCL crystal to maintain stable the optical feedback into the active region of the QCL crystal.

Abstract: A diode-laser is driven by a modulated voltage through a voltage-to-current converter. The modulated voltage has a fixed level determined by an applied fixed bias voltage and a variable level determined by a modulation voltage signal varying between minimum and maximum values. The fixed voltage level corresponds to a threshold level above which the diode-laser would provide laser-output. The modulation voltage signal is monitored and compared with a predetermined set value. If the monitored voltage signal falls below the set value, the modulated voltage is disconnected from the voltage-to-current converter and the output of the diode-laser falls to zero.

Abstract: A DC-coupled laser drive circuit (1) includes (i) a voltage drop section (14) provided between a power source and a pre-driver (12) and (ii) a voltage drop amount controlling section (16) for controlling, according to an output of the pre-driver (12), an amount of a voltage drop in the voltage drop section (14).

Abstract: An arbitrary waveform generator modifies the input signal to a laser diode driver circuit in order to reduce the overshoot/undershoot and provide a “flat-top” signal to the laser diode driver circuit. The input signal is modified based on the original received signal and the feedback from the laser diode by measuring the actual current flowing in the laser diode after the original signal is applied to the laser diode.

Abstract: A light source including a laser diode, and a method of operating a light source including a laser diode are disclosed. A driving current of the laser diode is dithered to cause a near-field light intensity distribution at an end facet to be perturbed, thereby reducing a time-averaged local intensity of the laser light at the end facet of the laser diode. The reduced time-averaged intensity reduces a possibility of a damage of the end facet.

Abstract: A method and device for providing a laser interlock having a first optical source, a first beam splitter, a second optical source, a detector, an interlock control system, and a means for producing dangerous optical energy. The first beam splitter is optically connected to the first optical source, the first detector and the second optical source. The detector is connected to the interlock control system. The interlock control system is connected to the means for producing dangerous optical energy and configured to terminate its optical energy production upon the detection of optical energy at the detector from the second optical source below a predetermined detector threshold. The second optical source produces an optical energy in response to optical energy from the first optical source. The optical energy from the second optical source has a different wavelength, polarization, modulation or combination thereof from the optical energy of the first optical source.

Abstract: Systems and methods are provided for generating an accurate, stable measurement for a laser bias current. The average current and the extinction ratio are controlled using a dual control loop. The transfer function between the laser and a monitor photo diode (MPD) is characterized. A laser driver control module predicts the average power that will be measured using the MPD relative to the data being transmitted, and this information is used to control a laser driver.

Abstract: In the field of the production of very high frequencies, for example from 1 gigahertz to several terahertz, by beating the frequencies of two laser beams together, a device includes a resonant optical cavity having very stable dimensions receiving the beams, with for each beam, an interrogation device of the resonant cavity supplying an electrical signal representing the difference in frequency between the light frequency of the beam and a resonance frequency of the resonant cavity. The frequency of each beam is servo controlled to minimize the frequency difference observed. The laser beams are produced by a dual-frequency laser producing two beams of different frequencies and orthogonal polarizations. A polarization separator is used for separate servo control of the beams according to polarization, and a polarizer is placed behind a main output of the resonant cavity producing an electromagnetic beam mixing the two polarizations and amplitude-modulated at the beat frequency.