Abstract: There is provided a time of flight sensor including a light source, a first pixel, a second pixel and a processor. The first pixel generates a first output signal without receiving reflected light from an external object illuminated by the light source. The second pixel generates a second output signal by receiving the reflected light from the external object illuminated by the light source. The processor calculates deviation compensation and deviation correction associated with temperature variation according to the first output signal to accordingly calibrate a distance calculated according to the second output signal.

Abstract: An optical circuit for routing a signal includes a coupler and first and second waveguides. The coupler has an input for the signal and has first and second outputs. The first waveguide has a first optical connection to the first output, and the second waveguide has a second optical connection to the second output. Both waveguides have the same propagation length. The first and second waveguides include different widths at the respective optical connections to the respective outputs. This coupler can be used with another input couplers, two additional waveguides, and two 2×2 output couplers to provide a 90-degree hybrid for mixing signal light and local oscillator light in a coherent receiver or the like.

Abstract: An optical device that can be used as an optical hybrid, e.g., in CMOS-compatible PICs. In an example embodiment, the optical device has a single optical input and four optical outputs. The two optical input signals to be mixed in the optical device are applied to the single optical input as transverse electric (TE) and transverse magnetic (TM) polarization components, respectively, of the corresponding polarization-multiplexed optical input signal. In response to the latter, the optical device causes the four outputs to receive four different relative-phase combinations of the two optical input signals, each combination being coupled into a TE waveguide mode at the respective optical output. A PIC having one or more instances of the optical device can be used, e.g., to implement a coherent optical receiver, wherein the TE and TM polarization components of the optical input signal are populated by a communication signal and a local-oscillator signal.

Abstract: In one or more particular implementations, a plurality of energy harvesting cells are provided, wherein each cell comprising a substrate supporting a least one electrical energy generating device, at least one control circuit for controlling at least the operation of the electrical energy generating device, wherein the energy harvesting cell is encased in a polymer Wherein the substrate has two opposing first sides each having a length L, a second side orthogonal to both first sides having a length equal to 2L, a third side opposed from the second side having a length of 4L, wherein the width of the substrate between the two opposing first sides is 8L.

Abstract: A cable modem (CM) system for utilizing additional bandwidth is disclosed. The system includes a receiver path, a feedback path, and a feedback receiver. The receiver path is configured to obtain a base signal having a base bandwidth from a downstream signal. The feedback path is configured to obtain an additional signal having an additional bandwidth from the downstream signal and convert the additional signal to a feedback bandwidth. The feedback receiver of a cable modem tuner is configured to process the additional signal using the feedback bandwidth.

Abstract: An electromagnetic wave phase/amplitude generation device includes a radiation unit configured to radiate electromagnetic waves of a random radiation pattern on a spatial frequency in which a state of the electromagnetic waves to be radiated for each divided region is determined to an imaging object, an imaging unit configured to generate a captured image by imaging scattered electromagnetic waves that are electromagnetic waves generated when the imaging object scatters the electromagnetic waves of the radiation pattern radiated by the radiation unit, and a generation unit configured to generate information indicating at least a phase and amplitude of the electromagnetic waves from the imaging object by performing an arithmetic sparsity constraint operation according to sparsity of the imaging object on the basis of the captured image generated by the imaging unit, information indicating the radiation pattern, and information indicating a signal of the imaging object.

Abstract: Optoelectronic modules operable to collect distance data and spectral data include demodulation pixels operable to collect spectral data and distance data via a time-of flight approach. The demodulation pixels include regions with varying charge-carrier mobilities. Multi-wavelength electromagnetic radiation incident on the demodulation pixels are separated into different portions wherein the respective portions are used to determine the composition of the incident multi-wavelength electromagnetic radiation. Accordingly, the optoelectronic module is used, for example, to collect colour images and 3D images, and/or ambient light levels and distance data. The demodulation pixels comprise contact nodes that generate potential regions that vary in magnitude with the lateral dimension of the semiconductor substrate. The potential regions conduct the photo-generated charges from the photo-sensitive detection region to a charge-collection region.

Abstract: Optical signal receivers and methods are provided that include multiple optical resonators, each of which receives a portion of an arriving optical signal. Various of the optical resonators are tuned or detuned from a carrier wavelength, and produce an intensity modulated output signal in response to modulation transitions in the arriving optical signal. A detector determines modulation transitions in the arriving optical signal by analyzing the intensity modulation output signals from the optical resonators.

Abstract: An apparatus for transmitting and receiving encoded optical signals having a data transmitter including: an optical emission device to output light energy as an optical beam having an operating bandwidth; a beam dividing device to receive and divide the operating bandwidth into plural communication bands; a frequency presence modulation unit to: spectrally segregate the bandwidth of at least one communication band into plural channels, and modulate the bandwidth to selectively produce an optical output signal with wavelengths that correspond to one or more of the channels, wherein presence and absence of energy within channels constitute an information packet for data communication; an optical pathway for bi-directional optical communication over a common optical path for transmitting the optical output signal and for receiving an optical input signal; and a data receiver to receive the optical output signal from the optical pathway.

Abstract: Optical signal receivers and methods are provided that include first and second optical resonators, each of which receives a portion of an arriving optical signal. The first optical resonator is tuned to a carrier wavelength and accumulates resonant optical signal energy whose output is disturbed responsive to a transition in the arriving optical signal. The second optical resonator is detuned from the carrier wavelength but also exhibits a disturbed output responsive to the transition in the arriving optical signal. Detectors detect the output disturbances from the two optical resonators to determine characteristics of the transition in the arriving optical signal.

Abstract: An optical beam scanning microscopy apparatus includes a light source adapted to emit an optical beam (2) and a microscope objective (1) adapted for focusing the optical beam (2) in an object plane (11). The microscopy apparatus includes first and second reflecting optical elements (M-X1, M-X2) disposed in series on the optical path of the optical beam (2) between the light source and the microscope objective (1), first elements of angular tilting (21, 25) adapted for tilting the first reflecting optical elements (M-X1, M-XY1) according to a first predetermined rotation angle (RX1), and second elements of angular tilting (22, 26) adapted for tilting the second reflecting optical elements (M-X2, M-XY2) according to a second rotation angle (RX2), in such a way as to angularly tilt the axis (12) of the optical beam (2) by pivoting about the center (O) of the pupil of the microscope objective (1).

Abstract: A phase difference error detecting unit detects a phase difference error component included in a phase difference component; a phase difference correcting unit corrects a first signal having the phase difference component as an angle of a cosine function and a second signal whose angle of the cosine function differs from that of the first signal by approximately ?/2 based on the detected phase difference error component; a phase operating unit operates a phase difference component from the first signal and the second signal corrected by the phase difference correcting unit; and the phase difference correcting unit obtains the corrected first signal and the corrected second signal by rotating a coordinate point represented by the first signal and the second signal on a polar coordinate plane by an angle corresponding to the phase difference error component.

Abstract: In some example embodiments, a demodulator may include an input polarization beam splitter (IPBS), input half waveplate (IHWP), cubical polarization beam splitter (CPBS), first reflector (R1), second reflector (R2), first quarter waveplate (QWP1), second quarter waveplate (QWP2), beam displacer (BD), output half waveplate (OHWP), and output polarization beam splitter (OPBS). The CPBS may be positioned to receive an output from IPBS. The IHWP may be positioned between IPBS and CPBS. The R1 may be positioned to receive and return a first output from CPBS. The QWP1 may be positioned between CPBS and R1. The R2 may be positioned to receive and return a second output from CPBS. The QWP2 may be positioned between CPBS and R2. The BD may be positioned to receive a third output from CPBS. The OPBS may be positioned to receive an output from BD. The OHWP may be positioned between BD and OPBS.

Abstract: A spectral sensing demodulator can include a programmable filter bank and a reconfigurable processor coupled to the programmable filter bank. The programmable filter bank can frequency demultiplex a plurality of frequency division multiplexed channels from a frequency band into a plurality of demultiplexed channels. The reconfigurable processor can include a plurality of reconfigurable resources. Each resource can be alternatively be configured to demodulate a demultiplexed channel and to monitor a demultiplexed channel.

Abstract: In an embodiment, a DP-QPSK demodulator includes first, second and third polarization beam splitters (“PBSs”) and first, second and third half waveplates (“HWPs”). The first HWP is positioned to receive an output of the first PBS. The second PBS is positioned to receive an output of the first HWP. The second HWP is positioned to receive an output of the second PBS. The third PBS is positioned to receive an output of the second HWP. The third HWP is positioned to receive an output of the third PBS.

Abstract: In an embodiment, a demodulator includes first, second, third, fourth and fifth beam displacers, a half waveplate, and a quarter waveplate. The second beam displacer is positioned to receive an output from the first beam displacer. The third beam displacer is positioned to receive an output from the second beam displacer. The half waveplate is positioned to receive an output from the third beam displacer. The fourth beam displacer is positioned to receive an output from the half waveplate. The fifth beam displacer is positioned to receive an output from the fourth beam displacer. The quarter waveplate is positioned between the fourth beam displacer and the fifth beam displacer.

Abstract: A delay interferometer includes a half beam splitter and two pentagonal prisms disposed on a substrate. The half beam splitter branches light to be measured which travels substantially in parallel with the substrate into two branched light beams. The pentagonal prisms respectively reflect the respective branched light beams such that the optical axes of the branched light beams are moved in parallel in a direction substantially perpendicular to the substrate by reflection. The half beam splitter combines the branched light beams reflected by the pentagonal prisms to generate interference light beams.

Abstract: An optical sampler includes a first and second 1×n optical beam splitters splitting an input optical sampling signal and an optical analog input signal into n parallel channels, respectively, a plurality of optical delay elements providing n parallel delayed input optical sampling signals, n photodiodes converting the n parallel optical analog input signals into n respective electrical output signals, and n optical modulators modulating the input optical sampling signal or the optical analog input signal by the respective electrical output signals, and providing n successive optical samples of the optical analog input signal. A plurality of output photodiodes and eADCs convert the n successive optical samples to n successive digital samples. The optical modulator may be a photodiode interconnected Mach-Zehnder Modulator. A method of sampling the optical analog input signal is disclosed.

Abstract: In an embodiment, a demodulator includes first, second, third, fourth and fifth beam displacers, a half waveplate, and a quarter waveplate. The second beam displacer is positioned to receive an output from the first beam displacer. The third beam displacer is positioned to receive an output from the second beam displacer. The half waveplate is positioned to receive an output from the third beam displacer. The fourth beam displacer is positioned to receive an output from the half waveplate. The fifth beam displacer is positioned to receive an output from the fourth beam displacer. The quarter waveplate is positioned between the fourth beam displacer and the fifth beam displacer.

Abstract: In a delay line interferometer inside a demodulator, with respect to polarization states of two split beams of light to be interfered with each other, p polarization and s polarization are reversed by a half beam splitter and, further, again multiplexed by the half beam splitter used for splitting so that interference beams of light are generated.

Abstract: Polarization based channeled images are optically demodulated to produce directly viewable images. A channeled image flux is converted to an unpolarized flux by a phosphor or other sensor, and the resulting converted flux is demodulated by modulating at a spatial frequency corresponding to a modulating frequency of the channeled image flux. After modulation, the converted flux is spatially filtered to remove or attenuate portions associated with the modulation frequency and harmonics thereof. The resulting baseband flux is then imaged by direct viewing, projection, or using an image sensor and a display.

Abstract: A spectral sensing demodulator can include a programmable filter bank and a reconfigurable processor coupled to the programmable filter bank. The programmable filter bank can frequency demultiplex a plurality of frequency division multiplexed channels from a frequency band into a plurality of demultiplexed channels. The reconfigurable processor can include a plurality of reconfigurable resources. Each resource can be alternatively be configured to demodulate a demultiplexed channel and to monitor a demultiplexed channel.

Abstract: This invention relates generally to the field of quasicrystalline structures. In preferred embodiments, the stopgap structure is more spherically symmetric than periodic structures facilitating the formation of stopgaps in nearly all directions because of higher rotational symmetries. More particularly, the invention relates to the use of quasicrystalline structures for optical, mechanical, electrical and magnetic purposes. In some embodiments, the invention relates to manipulating, controlling, modulating and directing waves including electromagnetic, sound, spin, and surface waves, for pre-selected range of wavelengths propagating in multiple directions.

Abstract: The present invention relates to a phase modulating apparatus capable of highly accurately and easily correcting the phase modulation characteristic of a reflective electric address spatial light modulator even when a condition of input light is changed. In the LCOS phase modulating apparatus, an input unit inputs the condition of the input light, and a processing unit sets an input value for each pixel. A correction value deriving unit determines a correction condition according to the condition of the input light. A control input value converting unit converts the input value set for each pixel into a corrected input value based on the correction condition. An LUT processing unit converts the corrected input value into a voltage value, and drives each pixel by using a drive voltage equivalent to the converted voltage value.

Abstract: The invention is a Demodulator for an Optical Analog Pulse Position Modulated signal suitable for inclusion in receivers for Free Space Optical communication systems. In one embodiment the Demodulator may use the pulse position modulated optical information signal and the clock signal with different wavelengths. By proper biasing of a Semiconductor Optical Amplifier and selection of wavelengths for the information signal and the clock signal, the performance of the Demodulator is made insensitive to noise in the received signals.

Abstract: A digital data transmission device is provided comprising optical waveguide architecture, a sideband generator, a modulation controller, an optical filter, a data mapping unit, and a phase controller. The optical waveguide architecture is configured to direct an optical signal through the sideband generator and the optical filter. The sideband generator comprises an electrooptic interferometer comprising first and second waveguide arms. The modulation controller is configured to generate an electrical drive signal to drive the sideband generator at a control voltage that is substantially larger than V? to generate optical frequency sidebands about a carrier frequency of the optical signal. The optical filter is configured to discriminate between the optical frequency sidebands and the optical carrier frequency such that optical sidebands of interest can be directed through the optical waveguide architecture as an optical millimeter wave signal.

Abstract: A phase difference error detecting unit detects a phase difference error component included in a phase difference component; a phase difference correcting unit corrects a first signal having the phase difference component as an angle of a cosine function and a second signal whose angle of the cosine function differs from that of the first signal by approximately ?/2 based on the detected phase difference error component; a phase operating unit operates a phase difference component from the first signal and the second signal corrected by the phase difference correcting unit; and the phase difference correcting unit obtains the corrected first signal and the corrected second signal by rotating a coordinate point represented by the first signal and the second signal on a polar coordinate plane by an angle corresponding to the phase difference error component.

Abstract: In some example embodiments, a demodulator may include an input polarization beam splitter (IPBS), input half waveplate (IHWP), cubical polarization beam splitter (CPBS), first reflector (R1), second reflector (R2), first quarter waveplate (QWP1), second quarter waveplate (QWP2), beam displacer (BD), output half waveplate (OHWP), and output polarization beam splitter (OPBS). The CPBS may be positioned to receive an output from IPBS. The IHWP may be positioned between IPBS and CPBS. The R1 may be positioned to receive and return a first output from CPBS. The QWP1 may be positioned between CPBS and R1. The R2 may be positioned to receive and return a second output from CPBS. The QWP2 may be positioned between CPBS and R2. The BD may be positioned to receive a third output from CPBS. The OPBS may be positioned to receive an output from BD. The OHWP may be positioned between BD and OPBS.

Abstract: The invention provides a PLC-type DP-QPSK demodulator that reduces connection loss between a polarization beam splitter and a 90-degree hybrid circuit and aims at reducing the manufacturing cost and an optical transmission system using the same. In an embodiment of the invention, a PLC-type DP-QPSK demodulator that receives a DP-QPSK signal includes one PLC chip having a planar lightwave circuit. Input ports and output ports of signal light are provided at an input end and at an output end of the PLC chip, respectively. Within the planar lightwave circuit, there are integrated a polarization beam splitter that splits the DP-QPSK signal into an X-polarization QPSK signal and a Y-polarization QPSK signal, and two 90-degree hybrid circuits that mix the X-polarization QPSK signal and local oscillation light and the Y-polarization QPSK signal and local oscillation light, respectively, split each QPSK signal into orthogonal components I, Q and output them.

Abstract: Apparatus for combining laser radiation (1) 5 which apparatus comprises a seed laser (2), a splitter (3), a plurality of amplifier chains (4), a reference amplifier chain (7), detection means (5). demodulator means (6), and phase control means (12), wherein each of the amplifier chains (4) comprises at least one optical amplifier (11), optical radiation (17) emitted from the seed laser (2) is split into the plurality of amplifier chains (4) by the splitter (3).

Abstract: A demodulating delay circuit with a planar lightwave circuit includes: an optical interferometer including input and output couplers, and a first arm waveguide connecting the couplers, and a shorter second arm waveguide. The interferometer delays each bit of a signal by one bit such that the delayed bit interferes with its adjacent bit, and has a bent form such that propagation directions of light in the couplers are different by 180 degrees. The couplers each include first and second waveguides. The first waveguide is longer and the waveguides are closely arranged in parallel at two positions thereby forming directional couplers. The input and output couplers are each configured as a wavelength insensitive coupler having a coupling ratio of 50 percent in a bandwidth used. The first waveguide of the input coupler is arranged on the same side as that on which the first waveguide of the output coupler is arranged.

Abstract: A PLC-type delay demodulation circuit includes a planar lightwave circuit that is provided on one PLC chip and demodulates a DQPSK signal. The planar lightwave circuit includes a Y-branch waveguide that branches a DQPSK-modulated optical signal into two optical signals and first and second MZIs that delay the branched optical signals by one bit. The length of a short arm waveguide of the first MZI is different from the length of a short arm waveguide of the second MZI, and the length of an optical path from the Y-branch waveguide to output ports of the first MZI through the short arm waveguide of the first MZI is equal to that of an optical path from the Y-branch waveguide to output ports of the second MZI through the short arm waveguide of the second MZI.

Abstract: This invention relates generally to devices constructed from quasicrystalline heterostructures. In preferred embodiments, two or more dielectric materials are arranged in a two- or three-dimensional space in a lattice pattern having at least a five-fold symmetry axis and not a six-fold symmetry axis, such that the quasicrystalline heterostructure exhibits an energy band structure in the space, the band structure having corresponding symmetry, which symmetry is forbidden in crystals, and which band structure comprises a complete band gap. The constructed devices are adapted for manipulating, controlling, modulating, trapping, reflecting and otherwise directing waves including electromagnetic, sound, spin, and surface waves, for a pre-selected range of wavelengths propagating within or through the heterostructure in multiple directions.

Abstract: Disclosed are a PLC-type delay demodulation circuit and a PLC-type optical interferometer capable of reducing the size of a PLC chip with respect to the arrangement of various kinds of light output waveguides. In a PLC-type delay demodulation circuit, arm waveguides of a first MZI and arm waveguides of a second MZI are formed so as to overlap each other in the same region of a planar lightwave circuit. The optical paths of the MZIs are arranged such that the propagation directions of two DQPSK signals branched by a Y-branch waveguide are opposite to each other.

Abstract: An optical signal processor may include an optical waveguide loop, and first and second phase modulator loops. Each of the first and second phase modulator loops may be in optical communication with the optical waveguide loop. The first and second phase modulator loops may include respective control signal input ports to control phase modulation applied by the first and second phase modulation loops. The optical waveguide loop may include two input ports to direct input signals in opposite directions in the optical waveguide loop and may further include an output port to output resulting signals.

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: The PLC-type delay demodulation circuit includes a planar lightwave circuit that is provided on one PLC chip and demodulates a DQPSK signal. The planar lightwave circuit includes a Y-branch waveguide that branches a DQPSK-modulated optical signal into two optical signals and first and second MZIs that delay the branched optical signals by one bit. A wave plate is provided in central portions of first and second arm waveguides of the first MZI and first and second arm waveguides of the second MZI in such a manner that the wave plate intersects all of the four arm waveguides, the four arm waveguides being close to one another in a portion where the wave plate is provided.

Abstract: A modulation device and method, and a demodulation device and method are provided. The modulation device modulates plural baseband signals to generate an optical signal, and comprises: plural modulation units for modulating plural electrical carriers with different frequencies by using the baseband signals respectively, to generate corresponding electrical modulated signals; a synthesizer for synthesizing the electrical modulated signals to generate a single electrical synthesized signal; an optical modulation unit for modulating a single optical carrier by using the electrical synthesized signal to generate the optical signal, wherein signal components corresponding to the baseband signals in the optical signal are distributed on both sides of a carrier frequency of the optical carrier at a predetermined frequency interval.

Abstract: A phase shift keyed demodulator includes first and second beam splitters, a first optical path, a second optical path, and a wavelength tuner. The first beam splitter splits an input signal into first and second output signals. The second beam splitter splits each first and second output signal into a transmitted signal and a reflected signal. The first optical path includes an optical path of each transmitted signal from a beam splitting surface to a reflector and back to the beam splitting surface. The second optical path includes an optical path of each reflected signal from the beam splitting surface to a mirror surface and back to the beam splitting surface. A path difference introduces a delay between the transmitted signal and the reflected signal. The wavelength tuner tunes the demodulator to a predetermined central wavelength and introduces a phase shift between first and second transmitted signals.

Abstract: A PLC-type delay demodulation circuit includes a planar lightwave circuit that is provided on one PLC chip and demodulates a DQPSK signal. The planar lightwave circuit includes a Y-branch waveguide that branches a DQPSK-modulated optical signal into two optical signals and first and second MZIs that delay the branched optical signals by one bit. The length of a short arm waveguide of the first MZI is different from the length of a short arm waveguide of the second MZI, and the length of an optical path from the Y-branch waveguide to output ports of the first MZI through the short arm waveguide of the first MZI is equal to that of an optical path from the Y-branch waveguide to output ports of the second MZI through the short arm waveguide of the second MZI.

Abstract: The embodiments of the present invention provides an optical demodulator, which includes a first reflective mirror, a second reflective mirror, a third reflective mirror, and an optical splitter. The optical splitter is configured to: split input light for the first time; split for the second time a first path of light reflected back by the first reflective mirror, where two paths of light obtained by splitting the first path of light are emitted to the first reflective mirror and the third reflective mirror respectively, split for the second time a second path of light reflected back by the second reflective mirror, where two paths of light obtained by splitting the second path of light are emitted to the first reflective mirror and the third reflective mirror respectively.

Abstract: A phase-shift keyed signal demodulator and method for demodulating is disclosed. An example demodulator includes N filters that receive inputs from a splitter and include transmission functions offset from one another. N pairs of photodiodes receive the transmitted and reflected beams from each filter and a decoder converts the outputs of the pairs of photodiodes to one or more data symbols.

Abstract: The present invention provides a 90-degree hybrid capable of miniaturization and also capable of a stable operation in a wide band. According to an embodiment of the present invention, a PLC-type 90-degree hybrid comprises: a PLC chip having a planar lightwave circuit formed therein; and a 90-degree hybrid circuit formed in the planar lightwave circuit, mixing a modulated signal light and an LO light to separate the signal light into quadrature components I and Q, and outputting the same. The 90-degree hybrid circuit includes: two Y-branch couplers each branching the signal light and the LO light; and two wavelength-independent directional couplers which cause LO lights passing through two paths and signal lights passing through two paths to interfere with each other, respectively. The above-described paths include waveguides having mutually inverted shapes and waveguides having an identical shape, and have a shape substantially symmetrical with respect to the signal light.

Abstract: An optical A/D converter according to the present invention includes an optical splitter that splits an analog input signal light into plurals, a plurality of Mach-Zehnder interferometers to which each of the signal lights split by the optical splitter is input, and plurality of optical/electrical conversion unit that convert each signal lights output from each Mach-Zehnder interferometer into a digital electrical signal, in which each Mach-Zehnder interferometer includes optical intensity-to-phase conversion unit that optically convert intensity of the input signal light into an amount of phase shift and the amount of phase shift differs for each Mach-Zehnder interferometer. Then, it is possible to provide a high speed and low power consuming optical demodulation circuit.

Abstract: Method and apparatus for controlling bias point of DQPSK demodulator are disclosed. The method comprises: step 1: respectively applying first and second bias voltages to I-path and Q-path, and applying identical pilot voltage signals to I-path and Q-path (S202); step 2: executing filtering processing on I-path and Q-path differential current signals collected by balance receiver and determining ?Iand ?Q (S204); step 3: performing feedback control to first and second bias voltages respectively according to ?I and ?Q so that ?I and ?Q respectively reaches expected bias point values of I-path and Q-path (S206); executing step 2 and 3 cyclically at preset regular intervals (S208), so that ?I and ?Q remains consistently the expected bias point values of I-path and Q-path. The solution enables bias point of DQPSK demodulator to be locked at any expected bias point value, facilitates realization of digitization, and is not easily influenced.

Abstract: A phase-shift keyed signal demodulator is disclosed including a filter positioned to receive an input beam, a first photodiode positioned to receive light reflected from the filter, and a second photodiode positioned to receive light transmitted through the filter. A difference between outputs of the first and second photodiodes is interpreted to determine a data value encoded in the input beam. In another embodiment N filters receive inputs from a splitter and include transmission functions offset from one another. N pairs of photo diodes receive the transmitted and reflected beams from each filter and a decoder converts the outputs of the pairs of photodiodes to one or more data symbols.

Abstract: Provided is a wavelength selective switch which includes: at least one input port; a dispersive portion for dispersing wavelength-multiplexed light input from the input port into wavelength-demultiplexed lights; a condenser element for condensing the wavelength-demultiplexed lights dispersed by the dispersive portion; a deflection portion having deflection elements for deflecting, for each wavelength-demultiplexed light condensed by the condenser element; at least one output port for outputting the wavelength-demultiplexed lights deflected by the deflection portion. A light-condensing position shift compensating element is disposed in an optical path between the input port and the dispersive portion or in the dispersive portion, for compensating light-condensing position shift of the wavelength-demultiplexed lights relative to the deflection element, light-condensing position shift being generated based on the arrangement of the input ports.

Abstract: A system comprises an optical processor comprising a sideband generator, an optical filter, and a phase-shift-keying (PSK) modulator, wherein: the sideband generator generates optical frequency sidebands about a carrier frequency of an optical signal; the optical filter discriminates between the optical frequency sidebands and the optical carrier frequency such that optical sidebands of interest can be used to generate an optical millimeter-wave signal; the PSK modulator comprises an optical splitter, an optical phase delay unit, two or more optical gates, and an optical combiner; the optical splitter divides the optical millimeter-wave signal into two or more intermediate signals; the optical phase delay unit delays one or more of the intermediate signals to create distinct phase relationship between them; the optical gates modulate each intermediate signal individually, based on a control input; and the optical combiner combines the gated intermediate signals into a single, PSK-modulated optical millimeter-

Abstract: Disclosed are a PLC-type delay demodulation circuit and a PLC-type optical interferometer capable of reducing the size of a PLC chip with respect to the arrangement of various kinds of light output waveguides. In a PLC-type delay demodulation circuit, arm waveguides of a first MZI and arm waveguides of a second MZI are formed so as to overlap each other in the same region of a planar lightwave circuit. The optical paths of the MZIs are arranged such that the propagation directions of two DQPSK signals branched by a Y-branch waveguide are opposite to each other.

Abstract: Methods and systems to control a gain applied to a free-space optical (FSO) signal to reduce time-varying intensity fluctuations. An optical pre-amplifier may provide a first, relatively moderate gain with low noise factor (NF). A second optical amplifier may provide a second gain. Amplification may include doped fiber amplification (DFA), such as erbium-doped fiber amplification (EDFA) and/or Raman amplification. A variable optical attenuator (VOA) may be controllable with a relatively fast response time to reduce the time-varying intensity fluctuations. The VOA may effectively control an overall system gain. The gain of the first and/or second optical amplifier may also be controllable to reduce the time-varying intensity fluctuations. Optical intensities may be detected at one or more locations to support one or more feed-forward and/or feedback control loops. A clamp may be applied when an optical power reaches a threshold.