Abstract: Disclosed is manufacturing method of an optical module including an optical/electrical converter, a receptacle, and a substrate, the method including: the receptacle that has a guide portion that aligns an optical connector ferrule that holds an end portion of an optical fiber and that has a device accommodating portion that matches with a profile of the optical/electrical converter; a process of accommodating the optical/electrical converter in the device accommodating portion; a process of securing the optical/electrical converter to the receptacle; and a process of electrically connecting to the substrate that electrically connects to the optical/electrical converter the optical/electrical converter secured to the receptacle.

Abstract: A new technique for sensing optical cavity mode mismatch using a mode converter formed from a cylindrical lens mode converting telescope, radio frequency quadrant photodiodes (RFQPDs), and a heterodyne detection scheme. The telescope allows the conversion of the Laguerre-Gauss basis to the Hermite-Gauss (HG) basis, which can be measured with quadrant photodiodes. Conversion to the HG basis is performed optically, measurement of mode mismatched signals is performed with the RFQPDs, and a feedback error signal is obtained with heterodyne detection.

Abstract: An optically-switch data network includes an optical data bus, an optical wavelength bus, and multiple nodes connected by the optical data bus and the optical wavelength bus. A first node determines that it has communication information to transmit to a second node, and determines if a first subscription signal is present on the optical wavelength bus. The first subscription signal includes a target frequency. If the first subscription signal is not present on the optical wavelength bus, the first node injects an optical communication signal onto the optical data bus. The optical communication signal includes the communication information and a carrier wave. The carrier wave includes the target frequency. The second node receives the optical communication signal using the optical data bus. If the first subscription signal is present on the optical wavelength bus, injection of the optical communication signal onto the optical data bus is postponed.

Abstract: Techniques are provided for single edge coupling of chips with integrated waveguides. For example, a package structure includes a first chip with a first critical edge, and a second chip with a second critical edge. The first and second chips include integrated waveguides with end portions that terminate on the first and second critical edges. The second chip includes a signal reflection structure that is configured to reflect an optical signal propagating in one or more of the integrated waveguides of the second chip. The first and second chips are edge-coupled at the first and second critical edges such that the end portions of the integrated waveguides of the first and second chips are aligned to each other, and wherein all signal input/output between the first and second chips occurs at the single edge-coupled interface.

Abstract: An Optical Add/Drop Multiplexer (OADM) node includes a plurality of degrees each having a multiplexer and a demultiplexer configured to interface to an optical section in an optical network; one or more channel holder sources configured to connect to corresponding multiplexers of the plurality of degrees and provide optical power at unoccupied portions of optical spectrum on the corresponding optical section to present a full-fill loading condition thereon; and control circuitry configured to locally detect a failure on the one or more channel holder sources affecting an upstream degree, and switch unoccupied optical spectrum filled with the channel holder signals from one or more downstream degrees to the upstream degree.

Abstract: To increase efficiency of optical control of phase shifting elements, arrangements comprising optical lenses are presented. The optical lenses may be arranged in reflective arrays so as to focus light from a light source on a phase shifting element, which may be placed in a feed point of an antenna, such as for example a lithographic antenna. In some embodiments, thus both optical controlling radiation and radio frequency, RF, power are concentrated in substantially the same place.

Abstract: A 2-D sensor array includes a semiconductor substrate and a plurality of pixels disposed on the semiconductor substrate. Each pixel includes a coupling region and a junction region, and a slab waveguide structure disposed on the semiconductor substrate and extending from the coupling region to the region. The slab waveguide includes a confinement layer disposed between a first cladding layer and a second cladding layer. The first cladding and the second cladding each have a refractive index that is lower than a refractive index of the confinement layer. Each pixel also includes a coupling structure disposed in the coupling region and within the slab waveguide. The coupling structure includes two materials having different indices of refraction arranged as a grating defined by a grating period. The junction region comprises a p-n junction in communication with electrical contacts for biasing and collection of carriers resulting from absorption of incident radiation.

Abstract: An optical transmitter includes: a plurality of laser diodes each of which outputs signal light having a wavelength that is different from a wavelength of other signal light; an optical multiplexer that is disposed adjacently to the laser diodes along a first direction, and that multiplexes the signal light output from the respective laser diodes; and a driving circuit that is disposed adjacently to the optical multiplexer along a second direction that is different from the first direction, and that drives the laser diodes. The optical multiplexer and the driving circuit are integrated.

Abstract: To provide a multiplexer that makes it possible to achieve a reduction in size and that minimizes the influence of the expansion of laser light on a multiplexing unit. A multiplexer is provided with a plurality of waveguides, multiplexing units that are provided at an intermediate location within the waveguides, and laser light sources, wherein: the first multiplexing unit is arranged at a position that is closest to the laser light sources; and the laser light sources that have an optical axis at a position that is separated from the transmission axis of the visible light that is introduced into the first multiplexing unit are arranged so that the optical axis is inclined with respect to the transmission axis and the outer periphery of laser light that expands at a predetermined expansion angle passes in front of the first multiplexing unit.

Abstract: A fiber optic module for use in a fiber optic terminal. The fiber optic module includes a body having a front end, a first body section including a first group of adapters on the front end and a first fiber routing arm having a first fiber retaining element at a free end of the first routing arm, and a second body section in stacked alignment with the first body section, wherein the second body section includes a second group of adapters on the front end and a second fiber routing arm having a second fiber retaining element at a free end of the second routing arm. The first body section and the second body section define an internal volume containing an optical splitter. The fiber optic module may also include a handle coupleable to the first body section.

Abstract: Aspects of the subject disclosure may include, a system for receiving first optical power signals via an optical fiber connected with a light source of a network device, converting the first optical power signals to electrical energy utilizing an optical power converter where the electrical energy is utilized as power by the system, and transmitting or receiving electromagnetic waves that propagate along a transmission medium without requiring an electrical return path, and wherein the electromagnetic waves convey data. Other embodiments are disclosed.

Abstract: An optical element includes a lens component and a filter. The lens component has first, second, third, fourth, fifth, sixth and seventh surfaces disposed around and parallel to a reference axis. The lens component further has spaced apart first and second collimating units formed on the first surface, and a third collimating unit formed on the second surface. The second collimating unit is located between the first and third collimating units. The third surface is formed with a groove defined by the fourth, fifth, sixth and seventh surfaces. The filter is disposed on the third surface, covers the groove, and has a first side surface facing the fourth, fifth, sixth and seventh surfaces, and a second side surface opposite to the first side surface.

Abstract: Aspects of the present disclosure describe planar lightwave circuit systems, methods and structures including a resonant mirror assembly having cascaded resonators that provide or otherwise facilitate the control of the transmissivity/reflectivity of a planar lightwave circuit (PLC)—or portion thereof—over a range of 0% to substantially 100%.

Abstract: Active optical cable (AOC) includes at least one optical fiber constituting a signal transmission medium and a plurality of optical data transceivers disposed at separate connector ends of the AOC assembly. The AOC includes a common laser source in a common laser hub (CLH) providing a source optical signal to the optical data transceivers. The optical data transceivers modulate the source optical signal to form modulated optical data signals. In some scenarios described herein, the CLH is disposed at an intermediate location along a length of the AOC between the separate connector ends of the AOC. Further, a central processor can be provided in the CLH to facilitate consolidated data processing operations for the plurality of optical data transceivers.

Abstract: A system and method for automatic discovery of an optical cable route. The method comprises: a light source power meter automatically monitoring an attenuation value of an optical cable fiber core, the optical cable fiber core being configured in an optical cable route; when the power meter generates an alarm, determining a level of the optical power alarm and reporting the alarm condition of the optical cable route in real time; and a drive automatically searching for available optical cable routes to provide options of available optical cable routes for real-time allocation of services.

Abstract: Embodiments of the invention describe apparatuses, optical systems, and methods for utilizing a dynamically reconfigurable optical transmitter. A laser array outputs a plurality of laser signals (which may further be modulated based on electrical signals), each of the plurality of laser signals having a wavelength, wherein the wavelength of each of the plurality of laser signals is tunable based on other electrical signals. An optical router receives the plurality of (modulated) laser signals at input ports and outputs the plurality of received (modulated) laser signals to one or more output ports based on the tuned wavelength of each of the plurality of received laser signals. This reconfigurable transmitter enables dynamic bandwidth allocation for multiple destinations via the tuning of the laser wavelengths.

Abstract: A 3-dimensional augmented reality (AR) world is a version of our “real” physical world augmented with virtual 3D objects that may be experienced by a user, such as someone who “sees” the virtual 3D objects through a smartphone or special eyewear. A shared 3D AR world is one in which multiple individuals can simultaneously experience the same augmented reality, even if they are not using the same devices. The shared 3D AR world is created by obtaining and synthesizing sensory and other inputs from various devices in use by different users, and providing augmented outputs adapted to different devices. The synthesis of a wide range of inputs allows the augmented reality effects to be realistic. The augmented reality effects may be pre-rendered by a cloud-based server to reduce the computational burden on user devices.

Abstract: A component for a quantum communication system, the component comprising: an input section and a decoder section, the input section comprising n waveguides, where n is an integer of at least 2, the decoder section comprising m decoders, where m is an integer of at least 2, each decoder comprising at least one waveguide, the input section and the decoder section being provided on a single substrate such that the waveguides are continuous and integrated between the input section and the decoder section, the waveguides of the input section and the decoder section being arranged such that light pulses enter the waveguides of the decoder section via the waveguides of the input section and the m decoders operate in parallel.

Abstract: The disclosures provide a method and apparatus for transmitting and receiving interface signals of a distributed base station. At least one channel of Common Public Radio Interface (CPRI) signals of a distributed base station are encapsulated into optical transport unit x (OTUx) signals in a frame structure of OTUx by adopting Generic Mapping Procedure (GMP) mapping scheme, wherein the x represents a transmission capacity and wherein the OTUx is adopted for providing a bandwidth required by the at least one channel of CPRI signals, and then the OTUx signals that bear the at least one channel of CPRI signals are sent.

Abstract: A system and method for in-service optical signal-to-noise ratio (OSNR) testing in optical communication systems. At least one OSNR test signal is combined onto an optical path with data channels. A receiver detects the received power of the OSNR test signal and provides output data representative of the OSNR of the system.

Abstract: Examples described herein relate to an optical switching device wherein a racetrack resonant structure is positioned to determine a frequency passband by coupling. In some examples, a first waveguide receives an input light signal. A second waveguide is positioned to enable the input light signal to couple between the first waveguide and the second waveguide through a first coupling gap. The racetrack resonant structure is positioned adjacent to the first coupling gap to enable the input light signal to couple between one of the first waveguide and the second waveguide and the racetrack resonant structure through a second coupling gap. Thus, the racetrack resonant structure is to determine the frequency passband such that a first portion of the input light signal that coincides with the frequency passband is output by the first waveguide, and a second portion of the input light signal that does not coincide with the frequency passband is output by the second waveguide.

Abstract: An optical filter for an optical data transmission system, including a substrate; a first and a second reflective structure which are spaced apart from each other such that they form a Fabry-Perot cavity, and at least one optical waveguide formed on or in the substrate, via which light can be coupled into the Fabry-Perot cavity and/or out of the Fabry-Perot cavity. The Fabry-Perot cavity formed by the first and the second reflective structure at least partly is a free-beam cavity, and the waveguide is an integrated waveguide which is formed by one or more layers arranged on the substrate, and the first and the second reflective structure are at least partly arranged in a cutout of the substrate or adjoin the cutout.

Abstract: An apparatus for generating a spectral image includes a filter to receive incident light. The filter has a variable refractive index. The apparatus also includes a modulator, operably coupled to the filter, to modulate the variable refractive index of the filter so as to generate a plurality of optical patterns from the incident light. The plurality of optical patterns represents the spectral image and each optical pattern in the plurality of optical patterns corresponds to a different modulation of the variable refractive index. The apparatus further includes a detector, in optical communication with the filter, to detect the plurality of optical patterns.

Abstract: There is provided an image processing device include an image processing section including a pipeline in which a plurality of processing modules is connected in series, each processing modules being configured to perform a predetermined process on input data, and the image processing section performing pipeline processing by the processing modules sequentially performing the process. Each of the processing modules includes a data buffer configured to temporarily store the data in unit of processing, and a control section configured to determine whether or not to store the data in the data buffer on the basis of a state of a data flow in the pipeline processing and a state of the data stored in the data buffer, and to select a path within the processing module by which the data is transferred on the basis of a determination result, and to control an operation of the data buffer.

Abstract: An apparatus includes a first and second VCSEL, each with an integrated lens. The VCSELs emit a first light beam having first optical modes at first wavelengths and a second light beam having second optical modes at second wavelengths. The apparatus also has an optical block with a first and second surface, a mirror coupled to the second surface, and a wavelength-selective filter coupled to the first surface. The first integrated lens mode matches the first beam to the optical block, and the second integrated lens mode matches the second beam to the optical block such that the first beam and second beam each have substantially a beam waist with a beam waist dimension at the first and second input region, respectively. An exit beam that includes light from the first beam and the second beam is output from the second surface of the optical block.

Abstract: The present invention relates to optical coupling systems that employ a multicore optical fiber. The system can be employed with two multicore optical fibers or with a single multicore optical fiber for use with an optical device. In particular, the system includes connectors having a lens assembly configured to relay optical signals and a ferrule to position the lens assembly. Additional details for making and using such systems are described herein.

Abstract: In accordance with certain embodiments, lighting systems include flexible light sheets and one or more sealed regions containing light-emitting elements, the sealed regions defined by seals between a top housing and a bottom housing and/or the light sheet.

Abstract: A storage system including a hardware module slot, configured to mechanically accommodate a first hardware module. The hardware module slot includes a hardware module data connector configured to electrically interface with the first hardware module inserted into the hardware module slot. The storage system further includes a fabric that includes a first switch. The first switch includes a first protocol interface to the hardware module data connector and is configured to enable first protocol communications between the first hardware module and a second hardware module. The fabric also includes a second switch that includes a second protocol interface to the hardware module data connector and is configured to enable second protocol communications between the first hardware module and the second hardware module.

Abstract: The specification relates to a microscopy system. The microscopy system includes a first laser emitting a first laser pulse, the first laser pulse being a pump beam; a second laser emitting a second laser pulse, the second laser pulse being a probe beam; time delay components for delaying the probe beam, wherein the time delay components delay the probe beam by 0.3 ps to 5 ns relative to the pump beam; an optical device for combining the pump beam and the delayed probe beam into a combined laser pulse, the combined laser pulse having a reduced focal spot size; a galvanometer scanning system for delivering the combined laser pulse to a focal spot in a focal plane, wherein the reduced focal spot size of the combined laser pulse initiates a stimulated emission of a targeted molecule, the stimulated emission having dipole-like backscatter, and a detector for detecting the dipole-like backscatter.

Abstract: In general, a branching configuration used in a wavelength division multiplexed (WDM) optical communication system, consistent with an embodiment of the present disclosure, includes a branch path with two or more optical paths cross-coupled to each other to provide redundant add and/or drop channel wavelengths to a branch terminal on each cross-coupled path. Accordingly, a fault condition affecting some of the cross-coupled optical paths may occur physically downstream from the cross-coupling, e.g., within a subsea umbilical cable or associated termination equipment. However, so long as at least one of the cross-coupled optical paths remains operational, then branch terminal equipment in the branch terminal may continue to receive channel wavelengths associated with a faulted optical path via an operational optical path by virtue of cross-coupling. Thus, the cross-coupled configuration reduces or otherwise eliminates the necessity of allocating spare optical paths within the subsea umbilical cable.

Abstract: A system and method including polarization modulation of supervisory signals for reducing interference with data signals in a wavelength division multiplexed optical communication system. At least one supervisory signal for monitoring a transmission path and/or elements coupled to the transmission path is fast polarization modulated and launched with data signals onto the path. Polarization modulating of the supervisory signal reduces impact of the supervisory signal on the data signals and improves system performance.

Abstract: An electro-optical sensor comprises an optical input configured to receive an optical carrier via an upstream fiber. The electro-optical sensor also includes an optical modulator configured to modulate an electrical signal onto the optical carrier to create an optical signal. The electro-optical sensor further includes an optical output configured to transmit the optical signal via a downstream fiber. The electro-optical sensor employs a variation output configured to transmit variation data indicating variation in the received optical carrier to support compensation for corresponding variation in the optical signal.

Abstract: A photonic integrated circuit (PIC) coupled to a substrate may be aligned with receptacles having guide pin structures configured to receive guide pins attached to a fiber assembly. The receptacles may be affixed to a surface of the substrate and/or the PIC to permit the fiber assembly to be removed during a solder reflow process while maintaining the alignment of the fiber assembly to the PIC when reconnected following the solder reflow process.

Abstract: A downhole tool apparatus is disclosed that includes an input fiber optic cable coupled to an electro-optic modulator. The input fiber optic cable propagates first and second actively orthogonally polarized light beams. The electro-optic modulator modulates the first and second actively orthogonally polarized light beams in response to a measurement data stream (e.g., telemetry data). A single light beam comprising the modulated first and second actively orthogonally polarized light beams is propagated over an output fiber optic cable so that the modulated first and the second actively orthogonally polarized light beams propagate the same data through the output fiber optic cable. Recovery circuitry coupled to the single light beam is then used to detect, demodulate, and decode the original measurement data stream.

Abstract: A flexible grid optical transceiver communicatively coupled to an optical network includes a coherent optical transmitter configured to generate a transmit signal at a first frequency/wavelength center and spanning a first one or more bins of optical spectrum; and a coherent optical receiver configured to receive a receive signal at a second frequency/wavelength center and spanning a second one or more bins of optical spectrum, wherein a size of each of the first one or more of bins and the second one or more of bins is based on a required roll off of a wavelength selective component in the optical network.

Abstract: The present invention relates to a driver system that can include an optical power based isolated power supply. The driver system can include an optical receiver that can be in communication with an optical transmitter to receive an optical signal. The optical receiver can be configured to convert the optical signal to a drive signal having a determined drive strength. The driver system can further include a driving circuit that can be configured to drive an input of the transistor device based on the drive signal according to a control signal defining an on-time and off-time for the driving circuit over a time interval. In some examples, the driver system can be integrated with a protection system.

Abstract: To provide a multiplexer that makes it possible to achieve a reduction in size and that minimizes the influence of the expansion of laser light on a multiplexing unit. A multiplexer is provided with a plurality of waveguides, multiplexing units that are provided at an intermediate location within the waveguides, and laser light sources, wherein: the first multiplexing unit is arranged at a position that is closest to the laser light sources; and the laser light sources that have an optical axis at a position that is separated from the transmission axis of the visible light that is introduced into the first multiplexing unit are arranged so that the optical axis is inclined with respect to the transmission axis and the outer periphery of laser light that expands at a predetermined expansion angle passes in front of the first multiplexing unit.

Abstract: An optical coupling device can include a first birefringent layer having opposing first and second surfaces. The first birefringent layer can split incident light received at the first surface into first and second beams. The first and second beams can have respective polarization orientations that are orthogonal to each other. The first birefringent layer can propagate the first and second beams along respective first and second paths within the first birefringent layer to the second surface. The first and second beams can be spatially separated at the second surface. A redirection layer facing the second surface of the first birefringent layer can include first and second grating couplers configured to respectively redirect the first and second beams to propagate within the redirection layer as respective third and fourth beams. In some examples, the third and fourth beams can have respective polarization orientations that are parallel to each other.

Abstract: An optical dispersion compensator integrated with a silicon photonics system including a first phase-shifter coupled to a second phase-shifter in parallel on the silicon substrate characterized in an athermal condition. The dispersion compensator further includes a third phase-shifter on the silicon substrate to the first phase-shifter and the second phase-shifter through two 2×2 splitters to form an optical loop. A second entry port of a first 2×2 splitter is for coupling with an input fiber and a second exit port of a second 2×2 splitter is for coupling with an output fiber. The optical loop is characterized by a total phase delay tunable via each of the first phase-shifter, the second phase-shifter, and the third phase-shifter such that a normal dispersion (>0) at a certain wavelength in the input fiber is substantially compensated and independent of temperature.

Abstract: A device for detecting a substance includes a light source arranged to emit a light signal through a sample cell, wherein the sample cell is arranged to temporally house a sample compound having a portion of the substance, and an optical processing module arranged to detect the light signal emitted through the sample cell to identify physical attributes of the light signal altered by the sample compound, wherein the physical attributes of the light signal altered by the sample compound is processed so as to detect the substance within the sample compound.

Abstract: There is described a transmitter device for transmitting an optical signal in the form of a plurality of subcarrier channels having different wavelengths. The device comprises first and second optical carrier emitters for emitting light in first and second subcarriers at first and second frequencies or polarizations respectively. First and second modulators are provided for modulating the first and second subcarriers with first and second modulation signals. An interleaver is provided for interleaving the first and second modulated subcarriers into the optical signal. First and second digital signal processing units are configured to pre-emphasize the first and second modulation signals to compensate for a wavelength-dependent power transfer function of the interleaver.

Abstract: There are provided an optical waveguide including cores arranged in a lattice form in which intersection loss is further reduced where, at each intersection of the cores including first and second cores extending in two intersecting directions, the first core is separated by the second core and a gap is formed between the second core and each of the end portions of the first core, and a position sensor using the same. The position sensor includes an optical waveguide including cores arranged in a lattice form. At each intersection of the cores including first and second cores extending in two intersecting directions, the first core is separated by the second core, and a gap is formed between the second core and each of the end portions of the first core. The width of the end portions of the first core is greater than the width of the second core.

Abstract: The present application discloses an add/drop multiplexer, including a first line board and a tributary board, where the first line board includes at least a first interface and a second interface, the first interface is disposed between the tributary board and the first line board, and the second interface is disposed on a network side of the first line board; the first line board is configured to output a first signal received from a first link through the second interface; the first line board is configured to output a second signal received from the first link to the tributary board through the first interface; and the first line board is configured to receive a third signal from the tributary board through the first interface, and input the third signal into the first link. An inter-board interface on a link is effectively eliminated, thereby improving a link bandwidth of a device.

Abstract: An optical receiver module that receives a wavelength-multiplexed optical signal is disclosed. The optical receiver module includes a first lens, an optical de-multiplexer, second lenses, and photodiodes. The first lens forms a beam waist of the wavelength-multiplexed optical signal output therefrom. The optical de-multiplexer de-multiplexes the wavelength-multiplexed optical signal into optical signals depending on wavelengths thereof and is installed so as to make optical paths for respective optical signals different from each other. The second lenses concentrate the optical signals onto the respective photodiodes. In the optical receiver module, the beam waist of the wavelength-multiplexed optical signal is set in a halfway between a longest path and a shortest path from the first lens to the second lenses.

Abstract: An optical receiver includes a cascade of optical filtering elements, each of which selects spectral components from incoming optical signals at a wavelengths aligned to filter passbands. The selected spectral components may be optically combined to form k pairs of intermediary signals, where k=log2(M). By comparing the k pairs of intermediary signals, k bits of a digital signal representing the incident signal may be generated. The filtering elements may be configured to perform demultiplexing and demodulation simultaneously, increasing functionality and reducing excess losses.

Abstract: Unlike most MEMS device configurations which simply switch between two positions in many optical devices the state of a MEMS mirror is important in all transition positions. It may determine the characteristics of an optical delay line system and by that an optical coherence tomography system in one application and in another the number of wavelength channels and the dynamic wavelength switching capabilities in the other. The role of the MEMS is essential and it is responsible for altering the paths of the different wavelengths in either device. It would be beneficial to improve the performance of such MEMS and thereby the performance of the optical components and optical systems they form part of. The inventors have established improvements to the design and implementation of such MEMS mirrors as well as optical waveguide technologies to in-plane optical processing as well as the mid infrared for optical spectroscopy.

Abstract: A semiconductor laser module includes a package; a plurality of semiconductor laser elements provided in the package; a member having a plurality of mounting surfaces on which the semiconductor laser elements are mounted, the mounting surfaces being separated from a bottom surface of the package by respective distances, the distances being gradually different from each other in a manner that the mounting surfaces as a whole form a step-like form; a plurality of lenses collimating respective laser beams emitted from the semiconductor laser elements; a plurality of reflection mirrors reflecting the respective laser beams; a condenser lens unit condensing the laser beams; an optical fiber where the optical beams condensed by the condenser lenses are optically coupled; and an optical filter disposed on optical lines of the respective laser beams reflected by the reflection mirrors and reflecting light having wavelengths different from the wavelengths of the laser beams.

Abstract: A regenerator system is provided for dynamic and asymmetric bandwidth capacity adjustment when exchanging data between a first remote network device and a second remote network device. The regenerator includes first and second couplers in communication with the first and second remote network devices, respectively, using a first communication medium that provides multiple communication channels, and at least one redirecting device operable to selectively configure at least one of the channels for either transmission of a signal from the first remote network device to the second remote network device, or transmission of the signal from the second remote network device to the first remote network device.

Abstract: A technique that does not increase the circuit size, does not make the circuit design and manufacturing difficult, and can reduce insertion loss when light enters from a slab waveguide toward an arrayed waveguide or when the light enters from the arrayed waveguide toward the slab waveguide. An optical waveguide provided with a slab waveguide in which a grating is formed therein at a distance from an end, and an arrayed waveguide whose end is connected to an end of the slab waveguide at a position where a constructive interference portion of a self-image of the grating is formed.

Abstract: A multi-stage interferometer circuit of the present invention includes: a multiplexing port; (N?1) stages of lattice type two-beam interferometers, wherein each stage includes a two-beam delay circuit having a path length difference of an integral multiple of M·? L/2, and wherein the two-beam delay circuit of the lattice type two-beam interferometer of the first stage is connected to the multiplexing port; an M-beam interferometer including: two sets of 1×(M/2) optical couplers connected to the first optical coupler of the lattice type two-beam interferometer at the final stage; an M-array delay circuit, each delay circuit of which has a delay length different from each other by ?L; and M×M optical couplers; and M demultiplexing ports, wherein one or more transversal filters are arranged inside the multi-stage interferometer circuit so that the light guided between the demultiplexing port and the multiplexing ports passes therethrough at least once.