Abstract: An optoelectronic transceiver includes an optoelectronic transmitter, an optoelectronic receiver, memory, and an interface. The memory is configured to store digital values representative of operating conditions of the optoelectronic transceiver. The interface is configured to receive from a host a request for data associated with a particular memory address, and respond to the host with a specific digital value of the digital values. The specific digital value is associated with the particular memory address received from the host. The optoelectronic transceiver may further include comparison logic configured to compare the digital values with limit values to generate flag values, wherein the flag values are stored as digital values in the memory.

Abstract: A laser component includes multiple laser devices arranged in an array to include different emission wavelengths, and a driving unit that, while switching each of the laser devices along the array into a turn-ON-enabled state that enables the laser device to turn to an ON state, brings one of the laser devices in the turn-ON-enabled state into an ON state.

Abstract: A laser light-source apparatus includes a control unit configured to perform control in such a manner that a seed light source is driven in a pulse oscillation mode of oscillating pulse light based on gain switching in an output permitted state where output of pulse light from the apparatus is permitted, and is driven in a continuous oscillation mode of oscillating continuous light in an output stopped state in which the output of the pulse light from the apparatus is stopped, with power of excitation light for a solid state amplifier maintained, and adjusts power of laser light input to the solid state amplifier from the seed light source in the continuous oscillation mode in such a manner that the solid state amplifier outputs light with substantially same average power in the output stopped state and in the output permitted state.

Abstract: A silicon-on-insulator chip including an arrayed waveguide grating (AWG) and an array of detector remodulators (DRMs) in a planar arrangement with the AWG such that the modulators or modulators and detectors of said DRMs are located within the same plane as the waveguides of the AWG; and wherein each DRM is located at an input or output of the AWG.

Abstract: THz device includes: a semiconductor substrate; a first semiconductor layer disposed on the semiconductor substrate; an active element formed by being laminated on the first semiconductor layer; a second electrode connected to the first semiconductor layer to be connected to a cathode K of the active element, the second electrode disposed on the semiconductor substrate; a first electrode connected to an anode A of the active element, the first electrode disposed on the semiconductor substrate to be opposite to the second electrode; a rear reflector metal layer disposed on a back side surface of the semiconductor substrate opposite to the first semiconductor layer, wherein the active element forms a resonator between the second and first electrodes, wherein electromagnetic waves are reflected on the rear reflector metal layer, and electromagnetic waves have a surface light-emission radiating pattern or surface light-receiving pattern in a vertical direction to the semiconductor substrate.

Abstract: An LED (light-emitting diode) driver for a photoplethysmography system, including a switched-mode operational amplifier for driving a driver transistor with a source-drain path in series with the LED. In a first clock phase in which the LED is disconnected from the driver transistor, the amplifier is coupled in unity gain mode, and a sampling capacitor stores a voltage corresponding to the offset and flicker noise of the amplifier; the gate of the driver transistor is precharged to a reference voltage in this first clock phase. In a second clock phase, the sampled voltage at the capacitor is subtracted from the reference voltage applied to the amplifier input, so that the LED drive is adjusted according to the sampled noise. A signal from the transmitter channel is forwarded to a noise/ripple remover in the receiving channel, to remove transmitter noise from the received signal.

Abstract: According to a transmitter, a receiving device, and a frequency offset correction method that are provided in embodiments of the present invention, after a power parameter of a pilot in an OFDM signal received by a receiving device is detected, a frequency offset value used to indicate a degree and a direction that are of a difference that is between a center frequency of a filter and a center frequency of a laser and that deviates from a first threshold is determined according to the power parameter of the pilot, and then the receiving device corrects the difference between the center frequency of the laser and the center frequency of the filter according to the determined frequency offset value, thereby implementing frequency offset correction of an OFDM system.

Abstract: A method includes receiving a mode control signal indicative of a current-mode or a voltage-mode. When the mode control signal is indicative of the voltage-mode, the method includes connecting a voltage-mode bias sub-circuit to an anode of a reflector-section diode and applying an adjustable bias voltage to bias a diode voltage at the anode of the reflector-section diode. The reflector-section diode is disposed on a shared substrate of a tunable laser. When the mode control signal is indicative of the current-mode, the method includes connecting a current-mode bias sub-circuit to the anode of the reflector-section diode and delivering an adjustable bias current to the anode of the reflector-section diode.

Abstract: A system based on recombination by superposition using a diffractive optical element DOE to combine the beams is provided. An optical diffractive assembly is placed upstream of a diffractive optical element to make it possible, via an appropriate imaging system, to optimize the combining efficiency in the ultra-short pulse regime.

Abstract: A heat-sinking package of an optical fiber combiner comprising an optical fiber combiner assembly and a case operates for a uniform temperature gradient inside the case. The optical fiber combiner assembly, fixed inside the case, comprises an overlay structure and an optical fiber combiner. The overlay structure comprises a long shallow receptacle divided by three compartments on upper side of the overlay structure, in which the optical fiber combiner is fixed with three epoxies respectively applied in the three compartments. The three epoxies with different refractive indices accommodated in the three compartments of the long shallow receptacle not only fix the optical fiber combiner in place but also serve thermal contacts to effectively disperse the heat generated in the optical fiber combiner to the overlay structure, further dispersing to surroundings of the case. The overlay structure further comprises one or more thermally conductive sheaths to more efficiently disperse the heat.

Abstract: A spatial modulator for RF beams (microwave (uW), millimeter wave (MMW), and sub-millimeter wave (sub-MMW)) using dynamically-writable highly-reflective regions, with sub-wavelength diffractive pattern spatial definition that is finer than the wavelength of the incident RF beam.

Abstract: Generally discussed herein are systems, devices, and methods for providing a frequency stabilized optical frequency comb, including frequency stabilizing the optical frequency comb to a laser that is frequency stabilized to an optical reference cavity, generating a low frequency electrical signal from the optical frequency comb, comparing the generated low frequency electrical signal to a reference low frequency electrical signal, determining an optical reference cavity drift based on the comparison, and then adjusting a frequency of the laser in response to the determined optical reference cavity drift.

Abstract: Apparatus and associated methods relate to an open-loop control circuit (OLCC) configured to determine a lasing element drive current as a function of a commanded optical power signal and a measured temperature signal, where the absolute value of the second derivative of the optical output power with respect to laser drive current exceeds a predetermined threshold. In an illustrative example, the absolute value of the second derivative may exceed the predetermined threshold in a non-linear operating region of the laser element. The non-linear operating region may represent, for example, a characteristic output power vs. drive current curve of the lasing element. The OLCC may provide laser peak power control for arbitrary peak power, within linear and non-linear regions of laser efficiency. In some embodiments, the OLCC may substantially improve control over laser optical output power over a wide dynamic range of, for example, temperature associated with the lasing element.

Abstract: A system and method for operating one or more light emitting devices is disclosed. In one example, the intensity of light provided by the one or more light emitting devices is adjusted responsive to a temperature of the one or more light emitting device. The light is adjusted via modifying a current supplied to the one or more light emitting devices.

Abstract: This semiconductor laser device includes a semiconductor laser chip and a spatial light modulator SLM optically coupled to the semiconductor laser chip. The semiconductor laser chip LDC includes an active layer 4, a pair of cladding layers 2 and 7 sandwiching the active layer 4, a diffraction grating layer 6 optically coupled to the active layer 4, and a drive electrode E3 that is disposed between the cladding layer 2 and the spatial light modulator SLM and supplies an electric current to the active layer 4, and the drive electrode E3 is positioned within an XY plane and has a plurality of openings as viewed from a Z-axis direction and has a non-periodic structure.

Abstract: An atomic oscillator includes an atom cell having an internal space in which alkali metal is encapsulated, a first light source section for making a resonance light pair, which is circularly polarized in the same direction as each other and resonates the alkali metal, enter the internal space using light from a first light source, a second light source for making adjustment light, which is circularly polarized in a rotational direction opposite to the direction of the resonance light pair and resonates the alkali metal, enter the internal space from the same side as the resonance light pair using light from a second light source, and an aperture member disposed between the internal space, and the first light source and the second light source.

Abstract: A mass spectrometry system includes a laser source, a trapping volume, first and second beam deflectors, and a deflector controller. The first and second beam deflectors are arranged on a path from the laser source to the trapping volume. The first beam deflector is configured to oscillate in a first direction at a first frequency and the second beam deflector configured to oscillate in a second direction orthogonal to the first direction at a second frequency. The deflector controller is configured to scan a scanned area within the trapping volume with the laser by controlling the oscillation of the first and second beam deflectors to cause ions trapped within the trapping volume to fragment into fragment ions. The scanned area has a first dimension defined by the oscillation in first direction and a second dimension defined by the oscillation in the second direction.

Abstract: An optical modulator apparatus may include a plurality of segment drivers, each segment driver having a unique offset voltage and driving but a portion or a segment of an electro-optical modulator. A modulating electrical signal may be applied to the segment drivers via a plurality of electrical delays. Parameters of the segment drivers may be selected so as to approximate a pre-defined transfer function, which may include a linear or a non-linear transfer function.

Abstract: The present invention relates to an active gain layer stack (21) for a vertical emitting laser device, the active gain layer stack (21) comprising a semiconductor material, wherein the semiconductor material is structured such that it forms at least one mesa (24) extending in a vertical direction. A transversally neighboring region (25) that at least partly surrounds said mesa (24) has a second refractive index (n2)—At least part of said mesa (24) has a first refractive index (n1) and a part of the neighboring region (25) transversally adjacent to said part of the mesa (24) has second refractive index (n 2)—Said first refractive index (n1) is higher than said second refractive index (n2) and a diameter in transversal direction of said mesa (24) is chosen such that a transversal confinement factor in the active gain layer stack (21) is increased.

Abstract: Methods and apparatus for controlling a bias voltage (20) supplied to an optical modulator that comprises a biasable component configurable to be biased by application of the bias voltage (20), the method comprising: providing a target for the modulator output power; applying, to the biasable component, a bias voltage (20) that biases the biasable component so that the output power is within a pre-defined range of the target; monitoring the output power and, if the output power of the modulator is determined to be outside the pre-defined range, varying the value of the bias voltage (20) to bring the output power back within the pre-defined range; and monitoring the optical input to the modulator and, if it has been disabled, maintaining the bias voltage (20) at its current level for a pre-determined length of time that is dependent upon how long the modulator has been operating at quadrature.

Abstract: An apparatus comprising a first electrical driver configured to generate a first binary voltage signal according to first data, a second electrical driver configured to generate a second binary voltage signal according to second data, wherein the first data and the second data are different, and a first optical waveguide arm coupled to the first electrical driver and the second electrical driver, wherein the first optical waveguide arm is configured to shift a first phase of a first optical signal propagating along the first optical waveguide arm according to a first voltage difference between the first binary voltage signal and the second binary voltage signal to produce a first multi-level phase-shifted optical signal.

Abstract: An electroabsorption modulator incorporates waveguiding regions along the length of the modulator that include quantum wells where at least two of the regions have quantum wells with different bandgaps. In one embodiment of the invention, the regions are arranged such that the quantum wells have bandgaps with decreasing bandgap energy along the length of the modulator from the modulator's input to its output. The bandgap energy of the quantum wells may be decreased in discrete steps or continuously. Advantageously, such an arrangement better distributes the optical absorption as well as the carrier density along the length of the modulator. Further advantageously, the modulator may handle increased optical power as compared with prior art modulators of similar dimensions, which allows for improved link gain when the optical modulator is used in an analog optical communication link.

Abstract: An amplifier including a pre-amplifier, an impedance converter, and a traveling wave amplifier (TWA) is disclosed. The pre-amplifier receives a differential input signal and has a pair of first output nodes that output a first differential signal by amplifying the differential input signal. Each first output node has first output impedance. The impedance converter includes a pair of first input nodes that receive the first differential signal and a pair of second output nodes that output a second differential signal. Each first input node has first input impedance greater than the first output impedance. The impedance converter converts the first differential signal into the second differential signal. Each second output node has second output impedance smaller than the first output impedance. The TWA includes a pair of transmission lines connected to the pair of the second output nodes. Each transmission line has characteristic impedance matching with the second output impedance.

Abstract: A device such as a laser diode is provided with a monitoring arrangement. The monitoring arrangement has voltage to current converters arranged to provide respectively currents which are proportional to the respective voltages on an anode and on a cathode of the laser diode. The monitoring arrangement provides a first output signal when the laser diode is on too long. That output signal is used to cause the laser diode to be switched off.

Abstract: A plane illumination apparatus has an optical device, an irradiation unit, and a light guide plate. The irradiation unit makes the coherent light beams scan the surface of the optical device, the light guide plate comprises a light take-out portion to take out coherent light beams to outside while making coherent light beams propagate between a first end face on which coherent light beams from the optical device are incident and a second end face provided to face the first end face, the specific zone is provided inside the light take-out portion or along the first end face, or along the second end face, the light take-out surface is a third end face that is connected to the first and second end faces, and the irradiation unit is provided at a rear side of a fourth end face that is an opposite side to the light take-out surface.

Abstract: Described herein are photonic integrated circuits (PICs) comprising a semiconductor optical amplifier (SOA) to output a signal comprising a plurality of wavelengths, a sensor to detect data associated with a power value of each wavelength of the output signal of the SOA, a filter to filter power values of one or more of the wavelengths of the output signal of the SOA, and control circuitry to control the filter to reduce a difference between a pre-determined power value of each filtered wavelength of the output signal of the SOA and the detected power value of each filtered wavelength of the output signal of the SOA.

Abstract: A laser device has a plurality of semiconductor lasers, a driving device that supplies a driving electric current to the semiconductor laser, a trigger generation circuit that sends a trigger signal to the driving device in order to output the driving electric current, and a wave-combining device that wave-combines laser light emitted from the semiconductor lasers at the combined-wave end, and at least any one of a signal transmitting time, an electric current transmitting time and a light transmitting time is adjusted so as to be the time set respectively for transmitting paths; wherein the signal transmitting time in which the trigger signal transmits over the signal path, the electric current transmitting time in which the laser light transmits over the electric current path, a light transmitting time in which the laser light transmits over the optical path.

Abstract: Multiple panel luminaires for light-based communication (LCom) and related techniques of use are disclosed. Each luminaire panel may comprise at least one solid-state light source, where the light sources are configured to output light. The luminaire may also include at least one modulator configured to modulate the light output of the light sources to allow for emission of LCom signals. The luminaire may also include a controller configured to synchronize timing of the LCom signals. In some cases, one panel may be configured to emit an LCom signal that is the inverse or duplicate of the LCom signal emitted from another panel. Panel signal inversion may be used to maintain a relatively constant level of light output from the luminaire and/or to create a virtual fiducial to provide orientation information. Using a multiple panel luminaire to transmit data may also result in improved data transmission rates and transmission reliability.

Abstract: Systems and methods for using a dispersion compensation circuit to directly modulate a laser. Techniques include calibrating a varactor bias point in a dispersion compensation circuit during manufacturing, but positioning the dispersion compensation circuit between a first attenuator and a second attenuator. Each attenuator, capable of reducing power of an input signal, may be adjustable so that the attenuation provided by each attenuator may be adjusted. The ratio of attenuation between attenuators may be adjusted based on either chirp of a laser or fiber length, and a varactor bias point may be adjusted by the other one of the chirp of the laser or fiber length. Thus, both chirp and fiber length may serve as a basis for adjusting attenuation between attenuators having a dispersion compensation circuit positioned between them.

Abstract: This display includes a control portion controlling a laser beam generation portion to output a first laser beam including a region of relaxation oscillation to a partial first image forming element included in a plurality of image forming elements and to output a second laser beam including no region of relaxation oscillation to a second image forming element, other than the first image forming element, included in the plurality of image forming elements.

Abstract: Systems and methods are provided herein. An exemplary system may include a laser source, the laser source having a laser center wavelength; at least one narrowband optical element receiving light emitted by the laser, the narrowband optical element having a filter center wavelength, the narrowband optical element being arranged such that the filter center wavelength is initially spectrally aligned with the laser center wavelength, the filter center wavelength changing in response to a temperature change such that the filter center wavelength is not substantially aligned with the laser center wavelength; and a passive adjustment mechanism coupled to the narrowband optical element, the passive adjustment mechanism including an actuator, the actuator moving in response to the temperature change, the actuator motion rotating the narrowband optical element, the rotation compensating for the temperature change such that the filter center wavelength and laser center wavelength remain spectrally aligned.

Abstract: Disclosed are a quantum key distribution terminal and system. An optical transceiving device and an electronics media board in a quantum key distribution system are organically integrated into a whole through an electronics back panel. A quantum key distribution terminal with a compact structure and a high integration level is provided, so that uniform testing, maintenance and management for various components in the quantum key distribution system can be realized, thereby realizing the integration and terminalization of the key distribution system. The same quantum key distribution terminal can also be used to conduct flexible networking, thereby setting up a quantum key distribution system on a point to point, local area network or metropolitan area network scale.

Abstract: The present invention provide a laser, where the laser is divided into a laser region and a grating adjustment region through a first electrical isolation layer; the laser region is configured to generate optical signals, where the optical signals include an optical signal with a wavelength corresponding to a “0” signal and an optical signal with a wavelength corresponding to a “1” signal; the grating adjustment region is configured to adjust a wavelength of the grating adjustment region by controlling current of the grating adjustment region, so that the optical signal with the wavelength corresponding to the “1” signal of the laser region passes through the grating adjustment region, and the optical signal with the wavelength corresponding to the “0” signal of the laser region returns to the laser region, thereby implementing suppression to chirp of a directly modulated laser.

Abstract: A detector remodulator comprising a silicon on insulator (SOI) waveguide platform including: a detector coupled to a first input waveguide; a modulator coupled to a second input waveguide and an output waveguide; and an electrical circuit connecting the detector to the modulator; wherein the detector, modulator, second input waveguide and output waveguide are arranged within the same horizontal plane as one another; and wherein the modulator includes a modulation waveguide region at which a semiconductor junction is set horizontally across the waveguide.

Abstract: The invention describes a mounting layer (200) for mounting at least two light emitting semiconductor devices. The mounting layer (200) comprises corner protrusion (205) and edge protrusion (210) for aligning the mounting layer (200) to the cooling structure (100). The mounting layer (200) further comprises aligning holes (215) defining mounting areas (270) for mounting the light emitting semiconductor devices. The mounting layer (200) enables, for example, manufacturing of a ?-channel cooler with mounting areas (270) by means of one direct bonding process. Tolerances may thus be reduced. The invention further describes a cooling structure (100) like a ?-channel cooler comprising such a mounting layer (200) and a light emitting structure comprising such a cooling structure (100). Furthermore, methods of manufacturing such a mounting layer (200), cooling structure (100) and light emitting structure are described.

Abstract: The embodiments of this disclosure provide an optical module, which expands the network bandwidth, eases a problem on dynamic bandwidth allocation. The optical module comprises an optical transceiver assembly and a control circuit, wherein the optical transceiver assembly comprises a first optical emitter and a second optical emitter; the control circuit is configured to control the first optical emitter to generate an optical signal of a first waveband, and the first optical emitter is configured to emit the optical signal of the first waveband to a transmission optical fiber; or, the control circuit is configured to control the second optical emitter to generate an optical signal of a second waveband, and the second optical emitter is configured to emit the optical signal of the second waveband to the transmission optical fiber. This disclosure is applied to an optical module of a wavelength division multiplex passive optical network.

Abstract: A computer-implemented method includes creating a test suite, wherein the test suite includes a plurality of test cases for execution on a plurality of test agents. The method distributes a first portion of test cases to any available test agents, wherein each test case out of the first portion of test cases does not have any associated preconditions. The receives test results and event information for a first test case out of the first portion of test cases from a first test agent. Responsive to determining the event information for the first test case includes a satisfied condition for a second test case with one or more associated preconditions, the method determines whether the satisfied condition for the second test case relates to a global variable or local variable.

Abstract: An organic light emitting display device having high transmittance with respect to external light and a method of manufacturing the same. The organic light emitting display device includes a substrate; a plurality of pixels formed on the substrate, each of the pixels including a first region that emits light and a second region that transmits external light; a plurality of thin film transistors disposed in the first region of each pixel; a plurality of first electrodes disposed in the first region of each pixel and electrically connected to the thin film transistors, respectively; a second electrode formed opposite to the plurality of first electrodes and comprising a plurality of transmission windows corresponding to the second regions; and an organic layer formed between the first electrodes and the second electrode. The transmission windows can be formed in the second electrode, that is, a cathode.

Abstract: Methods and systems are provided for using optical interferometry in the context of material modification processes such as surgical laser or welding applications. An imaging optical source that produces imaging light. A feedback controller controls at least one processing parameter of the material modification process based on an interferometry output generated using the imaging light. A method of processing interferograms is provided based on homodyne filtering. A method of generating a record of a material modification process using an interferometry output is provided.

Abstract: Provided herein is a link management method and apparatus in a multi-layered network, the method including confirming whether or not set virtual TE link resources can be committed to a virtual TE (traffic engineering) link; in response to the set virtual TE link resources being committable to the virtual TE link, committing the resources to the virtual TE link through resource commitment; in response to the set virtual TE link resources being not committable to the virtual TE link, determining whether or not the virtual TE link is an adaptive virtual TE link; and in response to the virtual TE link being determined as the adaptive virtual TE link and the adaptive bandwidth satisfying TE link setting standards, committing the resources to the virtual TE link.

Abstract: A method of calibrating a tunable laser having a distributed Bragg reflector includes, aligning a reflection peak of the distributed Bragg reflector with a target cavity mode of a plurality of cavity modes defined by a total optical path length inside a resonant cavity of the tunable laser. The method includes aligning a resultant lasing mode with a target wavelength of an output wavelength grid. The resultant lasing mode is formed by alignment of the reflection peak of the distributed Bragg reflector with the target cavity mode. The method also includes setting a target output power and a target extinction ratio of the tunable laser.

Abstract: A visible light communication apparatus and a method for visible light communication are provided. The method includes calculating a quantity of terminals in coverage of each of a plurality of visible light sources. The visible light sources include a first visible light source and a second visible light source. Determining a quantity of the sub-bands according to the quantity of terminals. The sub-bands include a first sub-band and a second sub-band. Distributing the first sub-band for the first visible light source and the second sub-band for the second visible light source according to the quantity of terminals in coverage of each of the visible light sources, in which the first sub-band and the second sub-band are different from each other. Allocating a bandwidth for each of the terminals according to the distributed sub-bands or a user requirement. Modulating a transmission data on one of the first sub-band and the second sub-band.

Abstract: An approach to proving a flexible grid architecture for time and wavelength division multiplexed passive optical networks is described. One embodiment includes an optical transmitter array configured to transmit an optical signal, an optical combiner coupled to the optical transmitter array configured to receive unlocked wavelengths from the optical transmitter array and output a single optical signal, and an optical amplifier coupled to the optical combiner configured to boost downstream optical power. In some embodiments, a WDM filter is coupled to the optical amplifier, and a tunable optical network units (ONUs) coupled to the WDM filter configured to transmit and receive the optical signals. In still other embodiments, a cyclic demultiplexer is coupled to the optical splitter and connects to an optical receiver array configured to receive optical signals.

Abstract: An image forming apparatus includes a signal generation unit configured to generate a light-emission signal. The signal generation unit stores information relating to a toner non-adherent area oriented light-emission pattern having been set beforehand. The toner non-adherent area oriented light-emission pattern is a light-emission pattern that causes a light irradiation unit to emit light in such a way as to prevent toner particles from adhering to a photosensitive member. When the light irradiation unit scans respective portions corresponding to two pixels adjacently disposed in a scanning direction a based on a part of the light-emission signal generated based on the toner non-adherent area oriented light-emission pattern, at least one of (a) light-emission start timing of light irradiation unit and (b) light-emission termination timing of the light irradiation unit is differentiated between the two pixels.

Abstract: Linearized optical transmitter units are described for a hybrid optical fiber coaxial cable network. The linearized optical transmitter unit can comprise a directly-modulated or externally-modulated laser optically coupled to an optical conduit directed to an optical fiber communications link and electrically coupled to an electrical RF source line that provides an RF source to drive the laser or an external modulator for a light beam from the laser. A linearization information electrical component comprising memory and/or a processor, and a data output configured to transmit linearization enabling data for input into a direct digital synthesis engine that enables the direct digital synthesis engine to generate an RF signal wherein nonlinear responses of the transmitter and/or the optical fiber communications link are pre-compensated, in which the data is specific for the optical transmitter and/or the optical fiber communications link.

Abstract: Embodiments for driving a laser diode includes generating a bias current having a duty cycle that is less than 100%. The current level of the bias current is insufficient to turn on the laser diode. A drive current is generated and combined with the bias current to turn on the laser diode almost instantly.

Abstract: An illumination device including a light source section including a laser light source, and allowing a laser light beam emitted from the laser light source to be output intermittently at a predetermined frequency; an optical element through which the laser light beam passes; and a driver section changing a coherency of the laser light beam by driving the optical element at a predetermined drive frequency. Expressions (1) |2×f2?n1×f1|?20 or (2) |2×f2?n2×f1|?3, (3) f2?20 or (4) f2?3, and (5) |f2?n1×f1|?20 or (6) |f2?n3×f1|?3 are satisfied, where f1 denotes the predetermined frequency in Hz, f2 denotes a variation frequency of luminance in illumination light output from the optical element in Hz, the variation frequency being generated by the driving of the optical element, n1 denotes an arbitrary integer of 0 to 10 both inclusive, and n2 and n3 denote respective predetermined integers of 0 to 10 both inclusive.

Abstract: In an optical device, a ring resonator, having a resonance wavelength, optically couples an optical signal that includes a wavelength from an input optical waveguide to an output optical waveguide. A monitoring mechanism in the optical device, which is optically coupled to the output optical waveguide, monitors an output optical signal on the output optical waveguide. For example, the monitoring mechanism may dither a temperature of the ring resonator at a frequency using a heater, and the output optical signal may be monitored by determining amplitude and phase information of the output optical signal at the frequency and twice the frequency. Moreover, control logic in the optical device adjusts the resonance wavelength based on the monitored output optical signal, where the adjustment is made without monitoring an input optical signal on the input optical waveguide.

Abstract: A tunable transmission optical filter is optically coupled between a laser section and semiconductor optical amplifier (SOA) section of a tunable laser device. The optical filter may be tuned to provide a high transmission near the lasing peak while suppressing a significant portion of back-propagating amplified spontaneous emission (ASE) of the SOA section. Without the optical filter, the laser output spectrum may develop side lobes of higher intensity after the ASE is amplified and reflected in the forward direction by the laser gain and mirror sections. While lessening the side lobes, the optical filter simultaneously transmits the laser peak for amplification by the SOA section.

Abstract: A wavelength tunable laser includes a gain section, a grating section, and an isolation section. The gain section generates and modulates an optical signal. The grating section is positioned adjacent to the gain section, and the isolation section is disposed between the gain section and the grating section. The isolation section impedes conduction of an electrical current between the gain section and the grating section.