Abstract: An apparatus includes an optical device to output a data-modulated optical signal, an electrical radio-frequency (RF) driver to drive the optical device with one or more RF drive signals, a photodetector to provide a measure of a light intensity output by the optical device, and an electronic controller. The electronic controller is configured to dither an amplitude of at least one of the one or more RF drive signals at a dithering frequency. The electronic controller is also configured to adjust one or more operation settings of at least one of the electrical RF driver and the optical device based on a component of the measure of a light intensity at the dithering frequency.

Abstract: In an approach to improve detecting and identifying objects through orbital synthetic aperture radar satellites, embodiments arrange an array of elements in a predetermined configuration, and process, by a threshold and signature analysis, detected peaks in processed image data. Further, embodiments generate a list of objects detections based on the processed peaks, and identify an object based on amplitude, polarization ratio, and polarization phase difference. Additionally, embodiments, classify the identified object based on the generated list of objects, and output, by a user interface, a list of probable object detections with position coordinates and identifications based on the classified identified objects, wherein the list of probable objects are above or within a predetermine threshold of confidence.

Abstract: Multi-state switchability is highly desirable in optoelectronic devices. For liquid crystal (LC) based devices, the stability of any configuration is achieved through a balance between imposed interactions and the LC's orientational elasticity. In most cases, the latter acts to resist deformation. By combining surface topography and chemical patterning, provided here are the effects of saddle-splay orientational elasticity, a property that, despite being intrinsic to all LCs, is routinely suppressed. Utilizing theory and continuum elastic calculations, provided here are example conditions for which, even using generic, achiral LC materials, spontaneously broken surface symmetries develop. Also provided are multi-stable devices in which a weak, but directional, applied field switches between spontaneously-polar surface state domains. The disclosed approach is useful in low-field and fast-switching optoelectronic devices, beyond those attainable by current technologies.

Abstract: Examples are disclosed relating to tunable attenuation of incident light using a switchable grating. One example provides an optical attenuator comprising a switchable grating configured to diffract light within a wavelength band at a diffraction angle. The optical attenuator further comprises an electrode pair configured to apply a voltage across the switchable grating to tune a proportion of incident light diffracted at the diffraction angle, and an optical dump to receive the proportion of incident light diffracted.

Abstract: A determination method includes causing the state in each of the plurality of pixels to correspond to a plurality of states of a plurality of bits of an Ising model, and setting an evaluation function for evaluating a degree of coincidence between the target image and the formed image as a function of the plurality of bits, and determining which one of the plurality of states is to be set for each of the plurality of pixels on the basis of states of the plurality of bits included in a result obtained by evaluating the evaluation function by an Ising machine.

Abstract: An optical transmission device includes: a control module generate a control signal output which includes a slope adjust signal and a bias voltage offset adjust signal according to an input signal indicating a dispersion amount an electrical level adjust signal; a multi-level pulse amplitude modulator; and an asymmetrical optical modulator which is controlled by the slope adjust signal to be operated at one of a positive slope and a negative slope of a transfer function of the asymmetrical optical modulator itself, and is controlled by the bias voltage offset adjust signal of the control signal output to offset a bias voltage point of the asymmetrical optical modulator itself from a quadrature point of the transfer function, and modulates the multi-level pulse amplitude modulation signal to an optical signal to generate an optical modulate signal having a chirp.

Abstract: A Bayesian model for predicting spectacle independence of one or more IOLs based on pre-clinical data (e.g., visual acuity value for one or more defocus values) of an IOL. The Bayesian model is trained to assign appropriate weights for different combinations of defocus values.

Abstract: A heterodyne phase-controlled beam-combiner system includes a laser source, a first beam splitter, a plurality of phase modulators, a tiled array and an optical mixer. The laser source generates a light beam, and the first beam splitter splits the light beam into multiple beamlets. A phase modulator tags each beamlet with an arbitrary phase dither signal corresponding to an arbitrary phase setpoint or offset, and a tiled array, including a number of lenslets, combines the tagged beamlets and directs the combined light to a second beam splitter. The optical mixer generates a heterodyne light including tagging information. A first output light of the second beam splitter is a target light directed to a target, and the arbitrary phase offset enables achieving a nonflat phase profile for beamlets to obtain the desired on-axis far-field intensity of the target light.

Abstract: Controller circuitry configured to control an optical transceiver of an optical line terminal, OLT, in a passive optical network, PON. The controller circuitry configured to derive a level of optical beat interference, OBI, of a received upstream optical signal from an optical transceiver of an optical network terminal, ONT; and set a wavelength of a downstream optical signal based on the level of OBI such that the wavelength is forced to differ from the upstream optical signal wavelength.

Abstract: A device includes an optical assembly and a digital projector. The optical assembly is configured to receive visible scene light at a backside of the optical assembly and to direct the visible scene light on an optical path toward an eyeward side. The optical assembly includes a dimming layer disposed on the optical path. The dimming layer includes a photochromic material that is configured to darken in response to exposure to a range of light wavelengths. The digital projector is disposed on the eyeward side of the optical assembly and is configured to selectively emit an activation light within the range of light wavelengths to activate a darkening of a region of the dimming layer to dim the visible scene light within the region.

Abstract: A hybrid electronic optical chip has a first photonic element with which a first diode is associated, a second photonic element with which a second diode is associated and a common electrical driver connected to the first and second diodes by a common electrical connection with opposite polarity. The electrical driver generates a common electrical drive signal divided in time into first and second drive signal components for independently driving the first and second photonic elements through the common electrical connection.

Abstract: In one embodiment, an optical state monitor includes an a light source detection layer for detecting electromagnetic radiation from an associated good. The optical state monitor uses a processor to evaluate the detected radiation, and make a comparison to a pre-defined optical state profile for the good. By making this comparison, the optical state detector is able to determine a quality for the good. In a particular construction, the optical state detector has an integral light source, and the light detection layer is printed as a thin film device. In this way, a stand-alone self-contained sensor is constructed for determining the good's current quality.

Abstract: A femtosecond laser multimodality molecular imaging system includes a near-infrared pulse generation device for providing near-infrared pulses with a central wavelength of 1010 nm to 1100 nm and a spectral width of less than 25 nm. The near-infrared pulses can excite an optical medium with strong nonlinearity to generate the femtosecond laser pulses with ultra-wide spectrum. A pulse measurement compression and control module measures and compensates the accumulated dispersion of the femtosecond laser pulses arriving at the tissue sample, so as to eliminate the “time domain broadening” effect as much as possible. The obtained shortest pulses can interact with the tissue sample to generate spectral signals from different modalities, thus providing a variety of nonlinear molecular image modalities.

Abstract: A light control device includes: a light control element including a first layer stack and a second layer stack which include electrodes provided on base members, respectively, and a liquid crystal layer sandwiched between the first and second layer stacks; a switching element connected between an AC power supply and the light control element; a comparator that detects whether or not the AC power supply is higher than a first voltage that is higher than 0 V and is lower than a maximum value of the AC power supply; and a control circuit that performs PWM control or PFM control on the switching element if the AC power supply is higher than the first voltage.

Abstract: Aspects of the subject technology relate to electronic devices with displays. The display includes an array of display pixels and one or more display-light sensors that monitor the display light generated by the display pixels. Using the display-light sensors, corrections to control signals for the display pixels can be provided to correct for array non-uniformities and/or pixel degradation over time. The display-light sensors may be provided in an array of display-light sensors mounted parallel to the array of display pixels. The array of display-light sensors can be in-plane with the display pixels or vertically displaced from the display pixels. The display-light sensors may be prevented from receiving non-display light such as ambient light.

Abstract: Aspects of the present disclosure describe systems, methods, and structures including integrated laser systems that employ external chirping structures that may advantageously include phase shifters and/or one or more filters. Further aspects of the present disclosure describe systems, methods, and structures including laser systems that employ external chirping structures that may advantageously include optical phased arrays.

Abstract: An optical atomic clock includes a fiber-coupled electro-optic modulator to phase modulate and suppress residual amplitude modulation of a frequency-doubled laser; a rubidium-enriched vapor cell configured to perform a two-photon transition of rubidium atoms to generate a fluorescence signal from the laser; and a differential lock mechanism to stabilize a frequency of the fluorescence signal to a resonance frequency of the two-photon transition of the rubidium atoms.

Abstract: A debugging method and device for an operating point voltage of a parallel MZI electro-optical modulator. The parallel MZI electro-optical modulator comprises a Parent MZI (2) formed by a parallel connection of a Child MZI (3) in an I path and a Child MZI (4) in a Q path.

Abstract: In order to project an image excluding zero-order light without adding extra modulation elements or pixels, without applying distortions, and without reducing luminance, a projection device includes: a phase modulator that modulates the phase of incident laser light; a Fourier transform lens that performs Fourier transformation on laser light, whose phase is modulated by the phase modulator; a mirror disposed on an image formation surface by the Fourier transform lens, and configured to reflect the laser light subjected to Fourier transformation by the Fourier transform lens; and a projection lens that enlarges the light reflected by the mirror and projects the light as projected light. The mirror guides zero-order light included in the Fourier-transformed laser light in a direction different from a direction of the projection lens, and reflects the light excluding zero-order light toward the projection lens.

Abstract: An optical phased array includes, in part, a multitude of optical signal emitters and a multitude of optical signal phase/delay elements each associated with and disposed between a different pair of the optical signal emitters. Each optical signal phase/delay element is adapted to cause a phase/delay shift between the optical signals emitted from its associated pair of optical signal emitters. Each optical signal phase/delay element is optically a ring resonator that includes a p-i-n junction. By varying the bias applied to the p-i-n junction, the phase/delay generated by the ring resonator is varied. Furthermore, each optical signal emitter is optionally an optical grating having a multitude of grooves. The groove lengths of the optical gratings are optionally selected so as to increase along the direction of travel of the input optical signal through the optical phase array.

Abstract: An optical transmission device includes: a first drive unit that drives a VOA adjusting an attenuation amount for an optical signal from an optical amplifier; a second drive unit that drives an excitation light source of the optical amplifier; a first FF control unit that sets a first set value for the first drive unit and performs FF control; a second FF control unit that sets a second set value for the second drive unit and performs the FF control; a first control unit that controls the second drive unit in a manner that causes an optical output power from the optical amplifier to attain a first control target value; and a switch unit that switches to the first control unit when the optical output power corresponding to the second set value is attained as a result of FF control of the second FF control unit.

Abstract: Devices and techniques for integrated optical data communication. A method of encoding symbols in an optical signal may include encoding a first symbol by injecting charge carriers, at a first rate, into a semiconductor device, such as a PIN diode. The method may also include encoding a second symbol by injecting charge carriers, at a second rate, into the semiconductor device. The first rate may exceed the second rate. A modulator driver circuit may include a resistive circuit coupled between supply terminal and drive terminals. The modulator driver circuit may also include a control circuit coupled between a data terminal and the resistive circuit. The control circuit may modulate a resistance of the resistive circuit by selectively coupling one or more of a plurality of portions of the resistive circuit to the drive terminal based on data to be optically encoded.

Abstract: A system and method are disclosed to characterize and correct for the effects of IQ skew and insertion loss in a coherent optical transmitter. The coherent optical transmitter receives a digital data signal including in-phase (I) and quadrature (Q) components and generates corresponding first and second dither signals. The first dither signal may be combined with the I component and the second dither signal may be combined with the Q component to generate I and Q combined signals, which may be converted into I and Q analog waveforms. An optical signal may be generated corresponding to the I and Q analog waveforms for transmission over an optical fiber. The IQ skew and/or insertion loss for the coherent optical transmitter may then be calculated based on the optical signal using the disclosed dither tone processing techniques in order to correct IQ skew and/or insertion loss impairment.

Abstract: Embodiments of the invention describe polarization insensitive optical devices utilizing polarization sensitive components. Light comprising at least one polarization state is received, and embodiments of the invention select a first optical path for light comprising a first polarization state or a second optical path for light comprising a second polarization state orthogonal to the first polarization state. The optical paths include components to at least amplify and/or modulate light comprising the first polarization state; the second optical path includes a polarization rotator to rotate light comprising the second polarization state to the first polarization state.

Abstract: An optoelectronic oscillator (OEO) is disclosed comprising an electronically tunable filter for transposing narrow pass band characteristics of a surface acoustic wave (SAW) filter to a microwave frequency to provide mode selection in the OEO. An OEO is disclosed comprising a set of optical domain components, a downconverter in communication with an output of the optical domain components, and a set of radio frequency (RF) domain components in communication with an output of the downconverter. The set of RF domain components comprises a tunable filter operating at a filter center frequency and having an output coupled to the set of optical domain components for communicating a mode selection result. The tunable filter including a tuner; and a sub-filter. The sub-filter operating at a fixed center frequency to provide mode selection and adjacent mode suppression with respect to the tunable filter center frequency.

Abstract: The disclosure is directed at a method and system for optical telecommunications performance monitoring via a dual frequency pilot tone. By applying a dual frequency pilot tone, with a first pilot tone frequency selected from a low frequency band and a second pilot tone frequency selected from a high frequency band, either simultaneously or alternatively, to a wavelength channel, one of the pilot tone frequencies may be adaptively selected to improve wavelength channel monitoring. More specifically, stimulated Raman scattering (SRS) caused crosstalk and chromatic dispersion (CD) caused pilot fading which adversely affect performance monitoring of the wavelength channel may be reduced.

Abstract: The present invention relates to telecommunication techniques and integrated circuit (IC) devices. More specifically, embodiments of the present invention provide an off-quadrature modulation system. Once an off-quadrature modulation position is determined, a ratio between DC power transfer amplitude and dither tone amplitude for a modulator is as a control loop target to stabilize off-quadrature modulation. DC power transfer amplitude is obtained by measuring and sampling the output of an optical modulator. Dither tone amplitude is obtained by measuring and sampling the modulator output and performing calculation using the optical modulator output values and corresponding dither tone values. There are other embodiments as well.

Abstract: An optical waveguide modulator with automatic bias control is disclosed. A portion of the modulator light is mixed with reference light and converted to one or more electrical feedback signals. An electrical feedback circuit controls the modulator bias responsive to the feedback signals.

Abstract: A fiber laser amplifier system that employs a technique for reducing polarization modulation instability (PMI) in a delivery fiber. The system includes a fiber amplifier that amplifies a seed beam and provides the amplified seed beam to a weakly polarization maintaining (PM) delivery fiber that delivers the amplified beam to a certain location. The polarization of the seed beam is controlled so that it aligns with the slow axis of the delivery fiber such that nonlinear birefringence that occurs in the delivery fiber is added to the natural birefringence of the delivery fiber so as to suppress the PMI in the delivery fiber.

Abstract: Methods and apparatuses for optical communications are provided. By way of example, an optical transceiver includes a processing device coupled to a memory, an optical subassembly, and a programmable device. The optical subassembly is configured to receive and modulate a first signal carrying high speed user data for transmission to a remote device over an optical link. The programmable device is coupled to the processing device and configured to receive data relating to digital diagnostic monitoring information (DDMI) of the optical transceiver from the processing device, perform forward error correction encoding on the DDMI data to produce a remote digital diagnostic monitoring (RDDM) signal, and send the RDDM signal to the optical subassembly as a second signal to modulate for transmission. The optical subassembly is configured to current modulate the second signal on the first signal to produce a double modulated optical signal for transmission to the remote device.

Abstract: A control circuit coupled to a light source and an optical modulator receives an electrical modulating signal with alternating active and idle temporal segments; the active temporal segments encode corresponding information. A portion of a source optical signal produced by the light source is transmitted by the modulator as the output optical signal. During idle temporal segments, the light source produces a non-zero source idle power level, and the modulator transmits at a constant idle transmission level. During active temporal segments, the light source produces a source average active power level, the modulator transmits at an average active transmission level that is higher than the idle transmission level, and the output optical signal is modulated in accordance with the electrical modulating signal, so that each active temporal segment of the output optical signal encodes the information of the corresponding active temporal segment of the electrical modulating signal.

Abstract: A method and an apparatus for digitally and automatically controlling a bias voltage of an electro-optic optical modulator are disclosed. The method includes: outputting a scanning bias voltage; acquiring a first optical signal; converting the first optical signal into a first electrical signal; outputting a first direct current signal; calculating an operating bias voltage at each operating point and a half-wave voltage; calculating an error feedback coefficient and a dither amplitude; outputting an operating bias voltage and a dither signal with the dither amplitude; acquiring a second optical signal; converting the second optical signal into a second electrical signal; outputting a harmonic component; calculating a harmonic amplitude and a shift phase; calculating a new bias voltage; and using the new bias voltage as the operating bias voltage.

Abstract: The present invention relates to a power conversion device in the power electronics field. An object of the present invention is to provide a technique of determining whether a switching element operates normally or not from a gate monitor signal of a power conversion device, and predicting a sign of a failure by obtaining the temperature of the switching element from a transient state of the switching voltage of the power conversion circuit as a component of the power conversion device without using a new signal path.

Abstract: Coherent spectroscopic methods are described, to measure the total phase difference during an extended interrogation interval between the signal delivered by a local oscillator (10) and that given by a quantum system (QS).

Abstract: Disclosed herein is a modulator (50) for polarization-division multiplexing (PDM) transmission. The modulator (50) comprises first and second DP-MZMs (12, 28) associated with first and second polarizations, each DP-MZM (12, 28) having an input for an in-phase and a quadrature driving signal for modulating the in-phase and quadrature components of an optical signal according to respective transfer functions, and a detector (58) suitable for detecting light comprising at least a portion of the light outputted by the first DP-MZM (12) and a portion of the light outputted by the second DP-MZM (28). The modulator (50) is adapted to superimpose a first pilot signal on one of the in-phase and quadrature driving signals of the first DP-MZM (12) and on one of the in-phase and quadrature driving signals of the second DP-MZM (28), and a second pilot signal on the respective other of the in-phase and quadrature driving signals of the first and second DP-MZMs (12, 28).

Abstract: The present application is directed to a method of short pulse generation. The method includes the step of creating, via electrical circuitry in a master oscillator, a square wave pulse with a predetermined pulse repetition rate. The method includes the step of retiming the square pulse with a clock. The method includes the step of recovering an electrical signal from the retimed square pulse. Further, the method includes the step of sending the recovered electrical signal to a modulator for modulating an optical signal.

Abstract: A transmitter includes a pilot loading apparatus, an optical modulator, and a pilot locking apparatus. The pilot locking apparatus is configured to determine a pilot operating point that is currently on a response curve and that is of the optical modulator, and a target initial amplitude of an electrical pilot signal. The pilot locking apparatus is further configured to control the pilot loading apparatus to adjust an initial amplitude of the electrical pilot signal to the target initial amplitude.

Abstract: In various embodiments, a beam-parameter adjustment system and focusing system alters a spatial power distribution of a radiation beams before the beam is coupled into an optical fiber or delivered to a workpiece.

Abstract: Methods and systems are provided, which pattern an illumination of a metrology target with respect to spectral ranges and/or polarizations, illuminate a metrology target by the patterned illumination, and measure radiation scattered from the target by directing, at a pupil plane, selected pupil plane pixels from a to respective single detector(s) by applying a collection pattern to the pupil plane pixels. Single detector measurements (compressive sensing) has increased light sensitivity which is utilized to pattern the illumination and further enhance the information content of detected scattered radiation with respect to predefined metrology parameters.

Abstract: Embodiments of the invention describe polarization insensitive optical devices utilizing polarization sensitive components. Light comprising at least one polarization state is received, and embodiments of the invention select a first optical path for light comprising a first polarization state or a second optical path for light comprising a second polarization state orthogonal to the first polarization state. The optical paths include components to at least amplify and/or modulate light comprising the first polarization state; the second optical path includes a polarization rotator to rotate light comprising the second polarization state to the first polarization state.

Abstract: A device comprises two polarization-selective optical elements for separately modulating wave fronts of two components of a collimated light beam, which are transversally polarized in orthogonal directions. The two polarization-selective optical elements are first and second partial areas of one spatial light modulator (SLM) diffracting the light beam in backward direction. A mirror arranged between the first and second partial areas of the SLM reflects the light beam coming from the first partial area towards the second partial area. A wave plate arranged between the first partial area and the second partial area of the SLM rotates the polarization directions of both components of the light beam by 90°. The mirror reflects the first and second components of the light beam as parallel bundles of light rays resulting in a lateral offset between the first and second components of the light beam behind the second partial area of the SLM.

Abstract: An optical system for a microlithographic projection exposure apparatus has an optical axis, at least one mirror arrangement having a plurality of mirror elements that are adjustable independently of one another for altering an angular distribution of the light reflected by the mirror arrangement, and a deflection device which includes, relative to the optical beam path downstream of the mirror arrangement, at least one deflection surface at which a deflection of the optical axis occurs. The at least one deflection surface has refractive power.

Abstract: An optical transmitter has a modulator for modulating data onto an optical signal for transmission to the receiver, the modulated signal having components at one or more constellations of points of different amplitudes and phases. The modulator is tunable such that distortions of the points of the one or more constellation can be tuned, and a tuning controller is provided for receiving a feedback signal from the receiver indicating a distortion measured at the receiver, and for tuning automatically the modulator to adjust the modulation based on the received feedback signal to pre-compensate for the measured distortion. Such pre-compensation can reduce the amount of distortion in the transmission system and thus enable more transmission capacity, without the need for a complex transmitter.

Abstract: A photodiode converts an optical signal output from a laser diode to a current signal, and a current-to-voltage conversion circuit converts the current signal to a voltage signal. A comparison amplifier compares the voltage signal with a reference voltage to control the current flowing from a variable current source and increases or decreases a bias current for driving the laser diode. The current-to-voltage conversion circuit comprises a resistor and a variable current source that are connected in parallel. Therefore, it is possible to change the bias current without changing the resistance value of the resistor and to avoid limiting the dynamic range of the optical signal that is output. In addition, since the resistance value of the resistor does not change, the loop gain does not change, thereby stabilizing the control operation.

Abstract: An optical transmitting/receiving system using a timing extracting method that allows a feed forward type of optimized structure exhibits increased cost and increased power consumption, therefore, an optical transmitting/receiving system according to the present invention includes an optical transmitter apparatus including a light source, an optical modulator, and a pseudo RZ carver; and an optical receiver apparatus including a coherent receiver, an AD converter, a main signal processing unit, and a timing extracting unit; wherein the pseudo RZ carver forms a dip in an optical signal phase-modulated with a frequency f by the optical modulator by dropping the optical intensity at a symbol transition point to approximate zero per n-symbol interval; the AD converter outputs a sample obtained by AD converting an electrical signal which is detected and outputted by the coherent receiver; the timing extracting unit extracts a clock component of a frequency f/n from the sample and derives from the clock component a

Abstract: In various embodiments, systems and methods can be structured to provide efficient active bidirectional mode-locked lasers, which can be used as intracavity phase interferometer (IPI) sensors. Stable bidirectional mode-locking can be achieved by a combination of a passive mechanism, a passively driven active mechanism, and a beat note detection system. Such systems can be used in guidance, navigation, and control systems, where attitude control of a vehicle relies on accurate measurements of its position and motion. In various embodiments, a detection system can be based on an all fiber intracavity phase interferometer (IPI) active laser capable of delivering accurate simultaneous measurements of all three degrees of rotation and position in a single, compact, cost effective unit. A variation of the same system can include a linear cavity laser for accurate measurements of acceleration without the use of any inertial masses. Additional apparatus, systems, and methods are disclosed.

Abstract: A device comprising, a mirror which is configured to oscillate in response to an oscillation signal, wherein the device is configured such that oscillation of the mirror will induce a signal; and a circuit in operable cooperation with the mirror such that an induced signal can be measured by the circuit and wherein the circuit is configured to provide an oscillation signal proportional to the measured induced signal; wherein the device is configured such that the mirror can receive the oscillation signal so that the oscillation signal is filtered due to oscillation limitations of mirror, to provide a filtered signal.

Abstract: A multi-beam combining apparatus includes a phase shifting section, a superposing section, an observing section and a phase control section. The phase shifting section generates a plurality of phase-shifted laser beams by shifting the phase of each of the plurality of laser beams. The superposing section generates a plurality of superposed laser beam by superposing the reference laser beam and each of the plurality of phase-shifted laser beams. The observing section generates interference pattern data of a spatial interference pattern which appears when observing each of the superposed laser beams. The phase control section carries out a feedback control of the phase shifts in the phase shifting section based on the interference pattern data obtained for every superposed laser beam, and thereby sets the plurality of phase-shifted laser beams to desired states.

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: 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.