Abstract: One embodiment is directed towards a stabilized laser including a laser to produce light at a frequency and a resonator coupled to the laser such that the light from the laser circulates therethrough. The laser also includes Pound-Drever-Hall (PDH) feedback electronics configured to adjust the frequency of the light from the laser to reduce phase noise in response to light sensed at the reflection port of the resonator and transmission port feedback electronics configured to adjust the frequency of the light from the laser toward resonance of the resonator at the transmission port in response to the light sensed at the transmission port of the resonator, wherein the transmission port feedback electronics adjust the frequency at a rate at least ten times slower than the PDH feedback electronics.

Abstract: The present invention provides apparatuses and methods for modulating the transmissivity of electrochromic devices utilizing a controller that provides a continuous potential that may be pulsed to the electrochromic device.

Abstract: A tunable Radio Frequency (RF) filter device includes a tunable optical source configured to generate an optical carrier signal, and a modulator coupled to the tunable optical source and configured to modulate the optical carrier signal with an RF input signal. The tunable RF filter device may also include first and second optical waveguides coupled to the modulator and having first and second dispersion slopes of opposite sign, and an optical-to-electrical converter coupled to the first and second optical waveguides and configured to generate an RF output signal with a frequency notch therein based upon the tunable optical source.

Abstract: An optical phased array (100) and a method (200) of forming an optical beam using an optical phased array (100) are disclosed. The optical phased array (100) comprises an optical head (116) for producing an output light beam, a spread spectrum modulation module (112), and a module (114) for controlling the phase of spread-spectrum-modulated light beams. The optical head (116) has a reference surface in the optical head (116) and comprises a number of sub-apertures (130) each for receiving a respective light beam. The reference surface (116) produces a backreflected light signal (126). The spread spectrum modulation module (112) modulates each of the light beams to have a spread spectrum signal for isolating the respective modulated light beam, which is provided to the optical head (116). The module (114) for controlling the phase of the spread-spectrum-modulated light beams is dependent upon the backreflected light signal (126) and the spread spectrum modulation.

Abstract: A polarimeter is proposed that utilizes additional Stokes parameter measurements to determine both an average Stokes vector, as well as any rotation of the state of polarization around the Stokes vector. The optical polarimeter is configured to measure the state of polarization (SOP) under multiple, different conditions that yield both averaged Stokes vector and at least one other secondary (filtered) Stokes vector, the latter thus being determined from a subset of the conditions used to create the average Stokes vector. The secondary Stokes vector created from a filtered input will necessarily exhibit changes over time as a function of polarization transformations (based on filter-dependent changes), while the average Stokes vector will retain a constant value. Thus, a comparison of the average Stokes vector to the changing secondary Stokes vector allows for these polarization-dependent transformations to be recognized.

Abstract: A nested loop system for combining coherent laser beams, The system includes multiple laser amplifiers each configured for emitting one of the laser beams, an output beam splitter configured for sampling each laser beam and for coupling each sampled laser beam to an inner feedback loop module, an output beam sampler configured for splitting the combined beam into a primary and a sampled output beam and for coupling the sampled output beam to the inner feedback loop module, multiple inner loop phase modulators each paired with one of the laser amplifiers, and the inner feedback loop module. For each laser amplifier the inner feedback loop module is configured to use the sampled output beam and the sampled laser beam associated with that laser amplifier to create a different inner loop feedback signal and to couple that inner loop feedback signal to that laser amplifier paired inner loop phase modulator.

Abstract: A thermally stabilized, high speed, micrometer-scale silicon electro-optic modulator is provided. Methods for maintaining desired temperatures in electro-optic modulators are also provided. The methods can be used to maintain high quality modulation in the presence of thermal variations from the surroundings. Direct current injection into the thermally stabilized electro-optic modulator is used to maintain the modulation performance of the modulator. The direct injected current changes the local temperature of the thermally stabilized electro-optic modulator to maintain its operation over a wide temperature range.

Abstract: A bias voltage control system and method for an optical IQ modulator are disclosed. The optical IQ modulator includes an I-branch Mach-Zehnder Modulator (MZM) to which an I-branch bias voltage is applied, a Q-branch MZM to which a Q-branch bias voltage is applied, and an optical phase shifter to which an orthogonal bias voltage is applied. The system comprises a photo-detector converting at least a part of an optical signal output by the optical IQ modulator to an electrical signal; an analog-to-digital converter converting the electrical signal to a digital signal; and a digital signal processor superimposing a first dither signal and a second dither signal on the I-branch bias voltage and the Q-branch bias voltage respectively to generate a first order harmonic signal and a second order harmonic signal, and controlling the bias voltages according to powers of a DC component, and the first and second order harmonic signals.

Abstract: The disclosure discloses a method and an apparatus for determining a bias point of a modulator, wherein the method includes: adding pilot signals to the bias voltages of the modulator; adjusting the bias point of the modulator at a predetermined step and acquiring a first harmonic amplitude value corresponding to each bias point in a backlight detection current signal output by the modulator; and determining a bias point corresponding to the maximum value of the first harmonic amplitude values associated with multiple bias points as the bias point of the modulator. By virtue of the disclosure, the detection of a difference frequency signal can be eliminated, thereby reducing the complexity and cost of a periphery control circuit while ensuring the control accuracy, effectively improving the stability and reliability of the control process, and improving the modulation and transmission performance of optical signals in the whole system.

Abstract: A terahertz continuous wave generator includes: an optical intensity modulator configured to modulate an optical signal into DSB optical signals; a local oscillator configured to generate a modulation signal for modulating the optical signal inputted to the optical intensity modulator into DSB optical signals; a notch filter configured to filter an optical signal with a specific frequency; an optical fiber amplifier configured to amplify an output signal of the optical intensity modulator; an optical circulator configured to transmit the optical signal inputted to the optical fiber amplifier to the notch filter and transmit the optical signal reflected from the notch filter to an input of the optical intensity modulator; an optical coupler configured to apply the optical signal to the optical intensity modulator; and an OE converter configured to photomix the DSB signals outputted through the notch filter.

Abstract: A laser system includes a laser light source which emits electromagnetic radiation, at least one optical amplifier which amplifies the radiation emitted from the laser light source, and a frequency multiplier which converts the amplified radiation by resonant frequency multiplying and/or summation-frequency generating. The laser system has a modulation facility which causes a modulation of the electromagnetic radiation emitted from the laser light source in such a manner that the spectrum encompasses a carrier frequency and at least one sideband, with the frequency multiplier being resonant at the carrier frequency and at the frequency of the at least one sideband.

Abstract: A method and a system is provided for configuring a device for correcting the effect of a medium on a light signal having propagated through the medium, the device including at least one optical element whose phase profiles are individually adjustable. The configuring system and method include propagating a reference signal and a disordered signal obtained at the output of the medium through the correcting device. An interference parameter is measured and optimized by modifying the phase profile of each of the optical elements of the correcting device. A method and a system is also provided for correcting the effect of a medium on a light signal having propagated through the medium.

Abstract: Techniques and devices based on optical resonators made of nonlinear optical materials and nonlinear wave mixing to generate RF or microwave oscillations using an active opto-electronic loop.

Abstract: A laser processing system quickly and flexibly modifies a processing beam to determine and implement an improved or optimum beam profile for a particular application (or a subset of the application). The system reduces the sensitivity of beam shaping subsystems to variations in the laser processing system, including those due to manufacturing tolerances, thermal drift, variations in component performance, and other sources of system variation. Certain embodiments also manipulate lower quality laser beams (higher M2 values) to provide acceptable shaped beam profiles.

Abstract: A method for determining, by a modulator assembly, an optimal drive point for a Mach-Zehnder modulator (MZM). The modulator assembly applies an electrical modulation signal to the MZM to modulate an optical input signal and create a modulated optical output signal, the modulated optical output having a spectrum that includes a first and third harmonic. The modulator assembly measures the difference in magnitude between the first harmonic and the third harmonic as the amplitude of the electrical modulation signal is varied, and determines a value for the amplitude of the electrical modulation signal that corresponds to a maximum difference between the first harmonic and the third harmonic.

Abstract: Lighting systems comprising a spectrum former upstream from a reflective pixelated spatial light modulator (reflective SLM), the SLM reflecting substantially all of the light in the spectrum into at least two different light paths, that do not reflect back to the light source or the spectrum former. At least one of the light paths acts as a projection light path and transmits desired light out of the lighting system. The lighting systems provide virtually any desired color(s) and intensity(s) of light, and avoid overheating problems by deflecting unwanted light and other electromagnetic radiation out of the system or to a heat management system. The systems can be part of another system, a luminaire, or any other suitable light source. The systems can provide virtually any desired light, from the light seen at the break of morning to specialized light for treating cancer or psoriasis, and may change color and intensity at speeds that are perceptually instantaneous.

Abstract: This document provides techniques, apparatus and designs for using electro-optic WGM resonators that support two different families of optical WGM modes with different quality factors in various applications. A radio frequency (RF) resonator is formed on the optical resonator and structured to supply an RF field and spatially overlaps the RF field of the RF resonator with the first and second optical whispering gallery modes to cause RF energy in the RF field at a first RF carrier frequency to couple with the first optical whispering gallery mode and RF energy in the RF field at a second RF carrier frequency to couple with the second optical whispering gallery mode.

Abstract: Imaging systems include a detector and a spatial light modulator (SLM) that is coupled so as to control image intensity at the detector based on predetermined detector limits. By iteratively adjusting SLM element values, image intensity at one or all detector elements or portions of an imaging detector can be controlled to be within limits. The SLM can be secured to the detector at a spacing such that the SLM is effectively at an image focal plane. In some applications, the SLM can be adjusted to impart visible or hidden watermarks to images or to reduce image intensity at one or a selected set of detector elements so as to reduce detector blooming.

Abstract: It is possible to implement a PMD generating function which can set a PMD vector for each wavelength over wide wavelength bands and which has a simple control algorithm. A PCD and a DR can be controlled independently because the PMD can be set for each wavelength. Input signal light 101 is input to a first birefringent crystal 104 through a first fiber collimator 102, and is output after a first PMD is added. This output light is input to the first Stokes mapping device 105, and is output after a state of polarization is variably controlled. This output light is input to a second birefringent crystal 106, and is output after a second PMD is added. This output light is input to a Second Stokes mapping device 107, and a state of polarization is variably controlled.

Abstract: Methods and apparatuses for controlling a bias point voltage for an external optical modulator are provided. A control loop is used to adjust a bias signal applied to an external modulator by determining unwanted signals at a predetermined frequency received by an optical receiver of the control loop and accounting for these unwanted signals when determining the bias point voltage.

Abstract: An optical modulation system has a function to compensate an operating point drift, which occurs in an MZ optical modulator, by carrying out feedback control with use of a low frequency signal. A judgment section judges stability of feedback control. In a case where the feedback control is determined to be unstable, a low frequency signal generating section switches a frequency of the low frequency signal from a first frequency to a second frequency.

Abstract: A laser system including a seed laser and an optical amplification subsystem, receiving an output of the seed laser and providing an amplified laser output, the optical amplification subsystem including a first plurality of amplifier assemblies, each of the first plurality of amplifier assemblies including a second plurality of optical amplifiers, and phase control circuitry including phase modulating functionality associated with each of the first plurality of amplifier assemblies.

Abstract: Photonic devices and techniques based on tunable single sideband (SSB) modulation in whispering gallery mode resonators formed of electro-optic materials to construct RF or microwave receivers.

Abstract: An optical probe includes a laser light source that emits laser light, a collimator lens that converts the laser light into parallel light, a light shape changing section that converts the parallel light into linear laser light, an irradiating section to irradiate an object with a selected part of the linear laser light, an image pickup section that picks up an image of the object based on the laser light reflected from the object, and a controller that controls irradiation of the linear laser light. The linear laser light is composed of a plurality of parts including one end part and the other end part; and the irradiating section irradiates the object with the parts of the linear laser light sequentially from the one end part to the other end part.

Abstract: According to an aspect of an embodiment, an optical modulation device includes a Mach-Zehnder modulator and a controller. The Mach-Zehnder modulator is supplied a drive signal and a bias voltage. The Mach-Zehnder modulator modulates inputted light on the bases of the drive signal and the bias voltage. The drive signal selectively is superimposes a predetermined frequency signal. The bias voltage selectively is superimposes the predetermined frequency signal. The controller selects a superimposing target which is the drive signal or the bias voltage so as to change modulation formats.

Abstract: Included are a first modulator, a second modulator, a first optical amplifier that amplifies an output of the first modulator at an amplification factor based on a first bias signal, a second optical amplifier that amplifies an output of the second modulator at an amplification factor based on a second bias signal, an optical phase adjuster that phase-rotates an output of the second optical amplifier, an optical multiplexer that multiplexes an output of the first optical amplifier with an output of the optical phase adjuster, and a second bias corrector that generates a first pulse signal and a second pulse signal, which are complementary to each other, and obtains a first bias value and a second bias value based on a change of strength of an output signal of the optical multiplexer. The first and second pulse signals are superimposed on the first and second bias signals, respectively.

Abstract: A lighting system operating using a digital mirror as its operative device. The digital mirror is used to shape the light which is a passed through advanced optical devices in order to produce an output.

Abstract: A modulating retroreflector system includes a modulating retroreflector having a plurality of multiple quantum well modulator pixels and at least one transimpedance amplifier. The transimpedance amplifier receives a photocurrent generated by at least one of the plurality of modulator pixels. Each pixel is capacitively coupled to a current driver, which applies a high frequency digital electrical signal to the pixel when the voltage at the output of the transimpedance amplifier exceeds a threshold value. The modulated output of the retroreflector is reflected toward the source of the received optical beam. The system activates high frequency current drivers for only the illuminated pixels, eliminating the need for a separate angle of incidence sensor and reducing power requirements.

Abstract: Apparatus, systems, and methods to construct and operate a radio frequency self-regenerated locked optical oscillator can be used in a variety of applications. Stable synchronization of an optical oscillator can be achieved by driving an amplitude modulator with a radio frequency (RF) signal regenerated from the cavity of the optical oscillator. Additional apparatus, systems, and methods are disclosed.

Abstract: A first linearly polarized bundle of rays of incident rays is converted by optical modulation with an input video signal into a second linearly polarized bundle of rays orthogonal to the first rays in polarization. The first rays pass through a polarizer before optically modulated. A second linearly polarized bundle of rays originally involved in the incident rays is reflected by the polarizer in a first direction. The second rays obtained by the optical modulation are reflected by the polarizer in a second direction. The second rays reflected in the second direction pass through another polarizer. A first linearly polarized bundle of rays involved in the reflected second rays is reflected by the other polarizer. The reflected first rays is detected by an optical sensor that is positioned outside an optical path of the second rays originally involved in the incident rays and reflected in the first direction.

Abstract: Techniques and devices based on optical resonators made of nonlinear optical materials and nonlinear wave mixing to generate RF or microwave oscillations using an active opto-electronic loop.

Abstract: Whispering gallery mode resonator based devices as photonic RF or microwave receivers.

Abstract: A control system and apparatus for use with an ultra-fast laser is provided. In another aspect of the present invention, the apparatus includes a laser, pulse shaper, detection device and control system. A multiphoton intrapulse interference method is used to characterize the spectral phase of laser pulses and to compensate any distortions in an additional aspect of the present invention. In another aspect of the present invention, a system employs multiphoton intrapulse interference phase scan. Furthermore, another aspect of the present invention locates a pulse shaper and/or MIIPS unit between a laser oscillator and an output of a laser amplifier.

Abstract: A laser processing system quickly and flexibly modifies a processing beam to determine and implement an improved or optimum beam profile for a particular application (or a subset of the application). The system reduces the sensitivity of beam shaping subsystems to variations in the laser processing system, including those due to manufacturing tolerances, thermal drift, variations in component performance, and other sources of system variation. Certain embodiments also manipulate lower quality laser beams (higher M2 values) to provide acceptable shaped beam profiles.

Abstract: A Mach-Zehnder modulator has an optical splitting element splitting an input optical signal into two optical signals that are conveyed by two optical waveguide arms, and an optical combining element combining the two optical signals into an output optical signal. Two traveling wave electrodes (TWEs) carry an electrical modulation signal to induce a change in phase of these two optical signals, and include a number of pairs of modulation electrodes positioned adjacent to the waveguide arms. At least some of the electrodes in one waveguide arm have a different shape (e.g., length or width) than the electrodes in the other waveguide arm to alter the effectiveness of the electrodes in inducing a phase change in the two optical signals.

Abstract: Disclosed herein are systems, methods, and non-transitory computer-readable storage media for simulating propagation of an electromagnetic field, performing phase retrieval, or sampling a band-limited function. A system practicing the method generates transformed data using a discrete Fourier transform which samples a band-limited function f(x) without interpolating or modifying received data associated with the function f(x), wherein an interval between repeated copies in a periodic extension of the function f(x) obtained from the discrete Fourier transform is associated with a sampling ratio Q, defined as a ratio of a sampling frequency to a band-limited frequency, and wherein Q is assigned a value between 1 and 2 such that substantially no aliasing occurs in the transformed data, and retrieves a phase in the received data based on the transformed data, wherein the phase is used as feedback to an optical system.

Abstract: A control apparatus for an external modulator that modulates light emitted from a light source based on an input signal, the control apparatus comprises: a low-frequency signal generating device that generates and outputs a low-frequency signal having a predetermined frequency; a signal superimposing device that superimposes a first modulation signal, which is the input signal on the low-frequency signal, to make a second modulation signal, and applies this second modulation signal to the external modulator; a low-frequency signal detecting device that detects the low-frequency signal component from an optical output of the external modulator, compares a phase of this detected low-frequency signal with a phase of a low-frequency signal output from the low-frequency signal generating device, and outputs a signal according to a phase difference; an operating point control device that controls based on an output signal of the low-frequency signal detecting device, so as to compensate for operating point drift of

Abstract: A method and apparatus for suppression of four-wave mixing using polarization control with a high power polarization maintaining fiber amplifier system. The apparatus includes a master oscillator (MO) that generates a beam; a polarization controller that receives the beam from the MO and transmits the beam with a desired polarization; a pre-amplifier that receives the beam from the polarization controller, pre-amplifies the beam, and transmits the beam; a high power fiber amplifier that receives the beam from the pre-amplifier, amplifies the beam, and transmits an output beam; and a polarization detector that detects the polarization of the output beam. The polarization detector transmits feedback to the polarization controller to ensure that the output beam components aligned with the principal birefringent axes of the high power fiber amplifier have approximately equal power.

Abstract: A bias controller and a method for controlling the bias of an electro-optic modulator are provided. In the method, for a received indication of modulator temperature, steps are provided for accessing a look-up table to determine a corresponding value of bias voltage, for a required bias point, to apply to the modulator. If no such value is stored, additional steps are provided to generate a pilot tone for input to the modulator and to recognize, from the signal content of a modulated optical signal output by the modulator, operation of the modulator at the required bias point, adjusting the value of bias voltage being applied to the modulator as required. When operation at the required bias point is recognized, the respective value of bias voltage for that modulator temperature is stored in the look-up table. The same method is provided to configure a bias controller in respect of a given modulator, if necessary ab initio.

Abstract: Examples of apparatus and methods are provided for controlling a bias in an optical modulator. An exemplary apparatus may comprise an optical modulator operable to modulate an optical signal. The optical modulation apparatus may comprise a photodetector disposed to receive at least a portion of the modulated optical signal. The optical modulation apparatus may comprise a bias controller coupled to both the optical modulator and the photodetector. The bias controller may be configured to receive a dither signal and to produce a bias feedback signal for the optical modulator. The bias feedback signal may be based on a ratio between an odd order harmonic signal of the modulated optical signal and an even order harmonic signal of the modulated optical signal.

Abstract: A microscope system as an optical microscope system for observing a specimen includes: an imaging optical system that forms an image of transmitted light or reflected light from the specimen; an illumination light source that illuminates illumination light on the specimen; an illumination optical system that has a first spatial light modulation element, which changes intensity distribution of the illumination light at a conjugate position of a pupil of the imaging optical system, and illuminates light, which is originated from the illumination light source, on the specimen; an image sensor that detects light through the imaging optical system; and a calculation section that calculates the intensity distribution of the illumination light appropriate for observation of the specimen on the basis of the intensity distribution of the illumination light formed by the first spatial light modulation element and output data detected by the image sensor.

Abstract: A system and method for locking the relative phase of multiple coherent optical signals, which compensates for optical phase changes induced by vibration or thermal changes in the environment.

Abstract: Photonic devices and techniques based on tunable single sideband (SSB) modulation in whispering gallery mode resonators formed of electro-optic materials to effectuate coupling between whispering gallery modes of different polarizations.

Abstract: An optical transmitter includes a light source that outputs light superposed with a pilot signal having a predetermined frequency; an optical modulating unit that modulates the light from the light source according to an input electric signal; a detecting unit that detects a high-output-side maximum value of signal light output from the optical modulating unit, a fluctuation width of the high-output-side maximum value, and a fluctuation width of a low-output-side minimum value; a bias-potential adjusting unit that adjusts a bias potential of an electric signal to be input to the optical modulating unit based on the detected maximum value; and an amplitude adjusting unit that adjusts an amplitude of the electric signal to be input to the optical modulating unit based on the fluctuation width of the high-output-side maximum value and the fluctuation width of the low-output-side minimum value.

Abstract: An apparatus comprises a first photonic crystal structure having a first photonic band gap distribution and configured to support a first electromagnetic signal, wherein the first photonic band gap distribution may vary according to a second electromagnetic signal.

Abstract: A tunable optical filter apparatus and method are disclosed. The apparatus may include a filter driver, a filter device, a detector device and a controller device. The filter driver generates a filter driver signal, including a dither signal. The controller device may be coupled to the detector device, the filter device and the filter driver. The controller device may receive the detector output signal and determine a ratio of the odd order harmonic signal to the even order harmonic signal with respect to the dither frequency. The controller device may also compare the ratio to a predetermined setpoint ratio and generate a control feedback signal for generating a new filter driver signal. The control feedback signal may be based on the comparison of the ratio of the odd order harmonic signal to the even order harmonic signal, to the predetermined setpoint ratio that corresponds to a desired filter operating frequency.

Abstract: The present disclosure relates to devices, systems and techniques for producing asynchronous delta-sigma modulated output signals from an optical input signal. In some examples, a modulator may include a first inverted integrator for producing a first integrated optical signal based on the optical input signal. Example modulators may also include a second inverted integrator for producing a second integrated optical signal based on the first integrated optical signal. Example modulators may also include an optical quantizer for producing an optical output signal based, at least in part, on the second integrated optical signal.

Abstract: Disclosed herein are systems, methods, and non-transitory computer-readable storage media for simulating propagation of an electromagnetic field, performing phase retrieval, or sampling a band-limited function. A system practicing the method generates transformed data using a discrete Fourier transform which samples a band-limited function f(x) without interpolating or modifying received data associated with the function f(x), wherein an interval between repeated copies in a periodic extension of the function f(x) obtained from the discrete Fourier transform is associated with a sampling ratio Q, defined as a ratio of a sampling frequency to a band-limited frequency, and wherein Q is assigned a value between 1 and 2 such that substantially no aliasing occurs in the transformed data, and retrieves a phase in the received data based on the transformed data, wherein the phase is used as feedback to an optical system.

Abstract: Devices and techniques for forming devices based on electro-optic whispering gallery mode (WGM) resonators by using spatially modulated electrodes and electro-optic whispering gallery mode (WGM) resonators that effectuate coupling between light in an optical whispering gallery mode in the TE mode and light in another optical whispering gallery mode in the TM mode.

Abstract: A modulating retroreflector system includes a modulating retroreflector having a plurality of multiple quantum well modulator pixels and at least one transimpedance amplifier. The transimpedance amplifier receives a photocurrent generated by at least one of the plurality of modulator pixels. Each pixel is capacitively coupled to a current driver, which applies a high frequency digital electrical signal to the pixel when the voltage at the output of the transimpedance amplifier exceeds a threshold value. The modulated output of the retroreflector is reflected toward the source of the received optical beam. The system activates high frequency current drivers for only the illuminated pixels, eliminating the need for a separate angle of incidence sensor and reducing power requirements.