Abstract: Microresonators, such as a microsphere resonators and planar microresonators, are optically coupled to waveguides for input and output of light. It is important that the relative positions of the microresonator and the waveguide are maintained stable, while still maintaining high cavity Q and ease of launching and extracting the optical beams. Structures are provided on a substrate that are useful for maintaining the position of the microresonator relative to the waveguide. The structures provide for vertical or horizontal coupling between the waveguide and the microresonator.

Abstract: The present invention is directed to an optical module, which stabilizes an oscillation characteristic of a laser by means of a simple configuration. To this end, a gain member, a partial reflection section connected to the gain member, and an optical device section connected to the partial reflection section are formed integrally into an apparatus of the present invention. The partial reflection section includes an optically-coupling waveguide section having a first light waveguide connected to the gain member, and a second light waveguide which has an optical axis differing from that of the first light waveguide and which is optically coupled to the first light waveguide and optically connected to the optical device section; and a first total reflection mirror formed at an end of the first light waveguide facing the optical device section.

Abstract: An optical microresonator includes microcylinder and spiral resonant waveguide formed on the microcylinder that optically couples light from an optical source waveguide to the microcylinder and slows light propagating along the microcylinder. A coupling element, for example, a diffraction grating can be operative with the resonant waveguide structure and configured to meet a desired phase matching A second microcylinder having a spiral resonant waveguide formed thereon can be positioned adjacent to the spiral resonant waveguide formed on the first microcylinder for coupling therewith. The spiral resonant waveguides on first and second microcylinders can be configured for slowing light propagating along the microcylinder.

Abstract: An optical channel monitor assembly for simultaneously measuring the optical power levels of multiple series of dense wavelength division multiplexed channels or the like traveling on separate optical fibers in an optical communications system includes an arrayed waveguide grating router having a first side and a second side, the first side including a first plurality of ports and the second side including a second plurality of ports, the first plurality of ports in optical communication with the second plurality of ports, wherein the first side includes a first input port for collectively receiving a first series of optical channels, wherein the second side includes a first plurality of output ports for individually delivering the first series of optical channels, wherein the second side includes a second input port for collectively receiving a second series of optical channels, and wherein the first side includes a second plurality of output ports for individually delivering the second series of optical cha

Abstract: Invention discloses an apparatus that provides linear optical modulation of light carrier signals by an electrical modulation signal. Linearized modulation is achieved through the selection of a spacing profile between two optical transmission waveguides. The spacing profile relates to a transfer function, the parameters of which are chosen to yield linear modulation within a particular dynamic range. A preferred embodiment discloses the invention being fabricated within a monolithic structure.

Abstract: A planar lightwave circuit type variable optical attenuator with a small polarization dependent loss is provided. By setting the waveguide birefringence (absolute value) in first and second optical coupler sections equal to or greater than 3.5×10?4, the polarization mode coupling is made equal to or less than ?25 dB, and the effect of the polarization dependence caused by the polarization mode coupling at the cross port of the first and second optical couplers is suppressed. In addition to or independently of this, the arm waveguide length can be designed to be equal to an integer multiple of the optical beat length obtained by dividing a used optical wavelength by the waveguide birefringence.

Abstract: The invention relates to an optoelectronic component and a method for producing it, in particular a waveguide structure, featuring at least one irradiation-sensitive structure in a layer structure of the optoelectronic component, the refractive index of the irradiation-sensitive structure being able to be permanently altered in a manner dependent on an irradiation. It is thus possible to change the properties of at least one layer, in particular of an optical waveguide, in a targeted manner by means of a simple method step.

Abstract: A low-ripple optical device comprising an optical demultiplexer structure and an optical multiplexer structure cascaded together wherein one of the structures exhibits n passband maxima and the other device exhibits n+1 passband maxima.

Abstract: One embodiment of the present invention provides a system that communicates between a first semiconductor die and a second semiconductor die through optical signaling. During operation, the system converts an electrical signal into an optical signal using an electrical-to-optical transducer located on a face of the first semiconductor die, wherein the first semiconductor die and the second semiconductor die are oriented face-to-face so that the optical signal generated on the first semiconductor die shines on the second semiconductor die. Upon receiving the optical signal on a face of the second semiconductor die, the system converts the optical signal into a corresponding electrical signal using an optical-to-electrical transducer located on the face of the second semiconductor die.

Abstract: Disclosed is a surface plasmon optic device that has a periodic array of apertures in a dielectric substrate and a metal film formed on the dielectric substrate and emits light from metal-air interface. The surface plasmon optic device includes a surface plasmon generating apparatus, a surface plasmon detecting apparatus, a surface plasmon controlling apparatus, an etching apparatus, etc. if a metal diffraction grating is disposed on the metal film having a well-defined interface, propagation of the surface plasmon can be efficiently reflected, divided and controlled. Further, radiating surface plasmon having a half period of a lattice constant formed at air-metal (1, 0) can be preserved at a distance of at least a few micron.

Abstract: An optical switch, an optical modulator, and a wavelength variable filter each have a simple configuration, which requires only a low driving voltage, which is independent of polarization, and which can operate at high speed. An optical switch includes a 3-dB coupler placed on an output, a 3-dB coupler placed on an output, and two optical waveguides connecting the input-side 3-dB coupler and the output-side 3-dB coupler together. The optical switch also includes a phase modulating section that applies electric fields to one or both of the two optical waveguides. At least two optical waveguides are a crystal material including KTaxNb1-xO3 (0<x<1) and KxLi1-xTayNb1-yO3 (0<x<1, 0<y<1), or KTaxNb1-xO3 or KxLi1-xTayNb1-yO3.

Abstract: An optical branching unit according to the invention, has on a substrate, a light input part which inputs light, an optical branch which branches the light input to the light input part at a predetermined ratio, a light output part which guides the light branched by the optical branch to a predetermined position, and a dummy pattern which is provided on a substrate independently of an area provided with the light input part, optical branch and light output part, made of the same material as the light input part, optical branch and light output part, and defined to have an area, so that an occupation rate, or a ratio of the dummy pattern to the area of a substrate except the light input part, optical branch and light output part, is 70% or higher.

Abstract: An optical switch, an optical modulator, and a wavelength variable filter each have a simple configuration, which requires only a low driving voltage, which is independent of polarization, and which can operate at high speed. An optical switch includes a 3-dB coupler placed on an output, a 3-dB coupler placed on an output, and two optical waveguides connecting the input-side 3-dB coupler and the output-side 3-dB coupler together. The optical switch also includes a phase modulating section that applies electric fields to one or both of the two optical waveguides. At least two optical waveguides are a crystal material including KTaxNb1-xO3 (0<x<1) and KxLi1-xTayNb1-yO3 (0<x<1, 0<y<1), or KTaxNb1-xO3 or KxLi1-xTayNb1-yO3.

Abstract: An optical apparatus comprises: a waveguide substrate; three planar optical waveguides formed on the substrate, each comprising a transmission core and cladding; a laser positioned to launch its optical output to propagate along the first waveguide; a photodetector positioned to receive an optical signal propagating along the second waveguide; and means formed on the substrate for i) transferring a first fraction of laser optical output propagating along the first waveguide to the second waveguide, and ii) transferring a second fraction of the laser optical output propagating along the first waveguide to the third waveguide. The transferring means may comprise: i) a pair of parallel spaced-apart tap core segments; ii) a branched splitter core; or iii) a lateral splitter core.

Abstract: A position of a first module (12a) with respect to an optical fiber (11) is determined in accordance with a receiving efficiency at the first module (12a) with respect to light emitted from the optical fiber (11). Power of light coupled into the optical fiber (11) from the first module (12a) is set in accordance with a value of a far-end reflectivity on a side of the first module (12a) in the position so as to satisfy a predetermined formula. By giving priority to determining a condition that significantly influences an improvement of an eye opening ratio, it is possible to manufacture an optical communication system at a low cost and with more freedom in manufacturing. Thus provided is a method of manufacturing an optical communication system, the method allowing for manufacturing an optical communication system at a low cost and with more freedom in manufacturing.

Abstract: An optical fiber coupler capable of providing a low loss, high coupling coefficient interface between conventional optical fibers and optical waveguide devices is provided. The novel coupler, which may be polarization maintaining, if a polarization maintaining preform is used in its fabrication includes a core, a cladding, a first end for interfacing with an optical fiber and a second end for interfacing with an optical waveguide device. The sizes of the core and cladding are gradually reduced from the first end to the second end in accordance with a predetermined reduction profile. Various parameters, such as refractive indices and sizes of the core and cladding and the reduction profile are selected to produce a low numerical aperture at the first end and a high numerical aperture at the second end, while advantageously minimizing insertion loss and maximizing the coupling coefficient at each end.

Abstract: The invention provides an optical switch including a substrate which has conductivity or semiconductivity, an optical waveguide layer which is formed on the substrate, and a control electrode which is formed on the optical waveguide layer. The optical waveguide layer includes an incident-side channel waveguide to which a light signal is incident and plural outgoing-side channel waveguides branched from the incident-side channel waveguide. The control electrode forms a reflection plane reflecting the incident light signal near a crossover portion of the plural outgoing-side channel waveguides by applying voltage to the optical waveguide layer with the substrate to control a refractive index of the optical waveguide layer, and switches propagation paths of the light signal.

Abstract: An optical switching element comprising: a multimode waveguide having an electro-optical effect; one or a plurality of first single mode waveguides; a plurality of second single mode waveguides; a first electrode arranged in the vicinity of one edge on one side of the multimode waveguide; a second electrode arranged in the vicinity of the other edge on the same side of the multimode waveguide; and a third electrode arranged on the other side of the multimode waveguide, over the first electrode and the second electrode being arranged so as to be positioned on luminescent spots in an optical mode field generated by the light propagating through the multimode waveguide, and an optical path being switched between the first single mode waveguide and the second single mode waveguide by applying voltage between the first electrode and the third electrode and between the second electrode and the third electrode, is provided.

Abstract: The present invention provides a set-reset flip-flop operating in an all-optical manner. In this invention, a set pulse is inputted from the setting port. In doing so, only oscillation in set mode is generated at the multi-mode interference portion in a waveguide. As a result, a non-inverting output Q is obtained from the non-inverting output port. This state is then continued even if the set pulse input goes off. Next, a reset pulse is inputted to the resetting port. In doing so, at the multi-mode interference portion, oscillation of light in the set mode is halted, and oscillation in the reset mode occurs. As a result, it is possible to obtain an inverting output Q-bar from the inverting output port. This state is then continued even if the reset pulse goes off.

Abstract: An OADM includes optical input and output; first and second bandpass filters with a first pass band, optically coupled to the optical input and output, respectively; third and fourth bandpass filters with a second pass band, optically coupled to reflection ports of the first and second bandpass filters, respectively; first and second cascaded series of channel filter assemblies optically coupled to the transmission ports of the first and second bandpass filters, respectively, and third and fourth cascaded series of channel filter assemblies optically coupled to the transmission ports of the third and fourth bandpass filters, respectively. The OADM may be extended or upgraded so as to accommodate the throughput of additional channels or wavelengths by extending the number of filters within each cascaded series of bandpass filters, where the transmission ports of the additional bandpass filters are optically coupled to respective additional cascaded series of channel filter assemblies.

Abstract: An optical connector used for inputting light to an optical element from an external optical system or outputting light from an optical element to an external optical system includes a photonic crystal having a periodic refractive index structure, and an optical waveguide to be optically coupled to the optical element and a region in which a plurality of defects are formed at intervals equal to or less than four times the refractive index period a of the photonic crystal are formed in the photonic crystal. The region has a size equal to or greater than the wavelength of the light input from the external optical system or the wavelength of the light output to the external optical system, and the external optical system and the optical waveguide are optically coupled to each other via the region. The optical connector has an improved optical coupling efficiency, can achieve optical coupling of a plurality of light components of different wavelengths, and can readily achieve alignment.

Abstract: An optical transmitting and receiving module for an optical waveguide performs both a transmitting operation and a receiving operation simultaneously. The linear first waveguide is provided such that one side is coupled to an optical fiber and the other side is coupled to a light receiving element. A second waveguide is coupled so as to meet and make an acute angle with the first waveguide. The second waveguide is shaped with a tapered portion adjacent to the first waveguide.

Abstract: An optical waveguide element having a directional coupler is disclosed. The element includes a first and a second waveguide located adjacent to each other at a predetermined portion for mode coupling, a first dummy waveguide extending from an one end of the second waveguide, a reflector installed on an end surface of the first dummy waveguide, and a second dummy waveguide located adjacent to the first dummy waveguide at a predetermined portion for a mode coupling. The optical signals progressing from the second dummy waveguide to the first dummy waveguide disappear while sequentially passing through the reflector and the second dummy waveguide. In the optical waveguide element, optical signals passing through the first dummy waveguide gradually disappear while passing through the reflector and the second dummy waveguide, thereby improving a bi-directional cross-talk.

Abstract: A free-space optically-coupled collimator for the efficient bidirectional transmission of an optical metrology beam emanating from a waveguide aperture of a waveguide optical transmission element, all contained in an isothermal nested enclosure, with the waveguide element mounted in a stress-free fashion. The focus of the collimator is set at the waveguide aperture of the waveguide optical transmission element, the optical axis of the collimator aligns with the optical metrology beam as it exits the waveguide aperture of the waveguide optical transmission element, and the numeric aperture of the collimator is equal to or larger than the numeric aperture of the optical metrology beam as it exits the waveguide aperture of the waveguide optical transmission element.

Abstract: Broadband optical switches based on adiabatic couplers having a pair of asymmetric waveguides with variable curvature sections include in a 2×2 configuration based on a Mach-Zehnder interferometer two such adiabatic couplers, and in a 1×2 or 2×1 configuration an adiabatic coupler and an Y-splitter. Each adiabatic coupler includes two waveguide branches of different but constant widths having curved sections with varying radii, separated over a coupling length by a changing spacing therebetween and blending in an asymmetric intersection area, and two symmetric branches. In the 2×2 switch, the two adiabatic couplers face each other with their respective symmetric branches, and are connected by the two identical arms along a main propagation axis in a mirror image. The utilization of the variable curvature adiabatic couplers in silica MZI switches on a silicon substrate provides switches with an exceptional broadband range (1.2-1.

Abstract: An optical waveguide circuit component according to the present invention is characterized by that a clad layer composed of quartz is provided on the surfaces of a substrate and core formed by quartz doped selectively on a quartz plate structure, and a lid or a cover member is fixed onto the clad layer by heat pressing. With this structure, it is possible to reduce the magnitude of a polarization-dependent loss (PDL) generated when the lid and clad layer are combined.

Abstract: Apparatuses and methods for forming displays are claimed. This invention relates to a display which may be conformal and which can receive information in order to alter or configure the display. In one embodiment, a flexible layer may be made to receive an array of blocks which drive a display material to provide an alterable or configurable display. This display is coupled to a receiver which receives data and drives the data onto the blocks causing the display to change. The receiver (and blocks) may be powered by a signal from a transmitter which beams the information to the receiver. The receiver in turn controls the update of the display information on the display. Another embodiment of the invention has a receiver coupled to each block. The receiver also may be independent from the block and may be deposited onto the flexible layer.

Abstract: An optical isolator for coupling light from a first waveguide to a second waveguide is disclosed. The optical isolator utilizes a resonator coupled to the first and second optical waveguides. The resonator has a resonance at ? for light traveling from the first optical waveguide to the second optical waveguide; however, the resonator does not have a resonance at ? for light traveling from the second waveguide to the first waveguide. The resonator can use a layer of ferromagnetic material in an applied magnetic field. The magnetic field within the ferromagnetic material varies in strength and/or direction over the layer of ferromagnetic material. The magnetic field can be generated by an external magnetic field that varies over the layer of ferromagnetic material. Alternatively, the resonator can include a layer of ferromagnetic metal that overlies a portion of the layer of ferromagnetic material and a constant external magnetic field.

Abstract: A mode coupler structure includes a discriminating structure that discriminates between various incoming modes from an input optical fiber structure. A waveguide structure is coupled to the discriminating structure that couples light not discriminated by the discriminating structure to an output optical fiber structure.

Abstract: In an optical wavelength division multiplexed access system, a center unit (OSU) and n optical network units (ONUs) are connected together via a wavelength splitter and optical fiber transmission lines, and downstream optical signals from the OSU to the ONUs and upstream optical signals from the ONUs to the OSU are transmitted in both directions, the wavelength spacing ??d (optical frequency spacing ?fd) of the downstream optical signals is set to twice or more the wavelength spacing ??u (optical frequency spacing ?fu) of the upstream optical signals, each ONU transmits an upstream optical signal whose optical spectral width is twice or more ??u (?fu), and the wavelength splitter spectrum slices the upstream signals transmitted from the ONUs into wavelengths (optical frequencies) whose optical spectral widths are mutually different within ??u (?fu), and wavelength-division multiplexes them and transmits to the OSU.

Abstract: An all optical chopping device for shaping and reshaping comprising an all optical AND logic gate having a first input for receiving a first optical signal, a second input for receiving a second optical signal and at least one output. The AND gate may be arranged to produce at least at one output thereof an optical output signal corresponding to a portion of the AND product of the first optical signal and the second optical signals. The optical output signal may be narrower than at least one of the first optical signal and the second optical signal.

Abstract: A method of improving a grating design function describing a refractive index variation defining a multi-channel grating structure in a waveguide material, the improvement being a reduced maximum refractive index variation in the waveguide material along the grating structure while maintaining a desired functional spectral domain in a spectral response function associated with the design function, the method comprising the steps of modifying a first design function to generate a second design function having a reduced maximum amplitude compared with the first design function, determining a second response function associated with the second design function, modifying the second response function to create a third response function having a desired functional spectral domain, and determining a third design function associated with the third response function, and iterating the method steps until the desired improvement is achieved, wherein the third design function of the previous iteration takes the place of

Abstract: The invention relates to a glass fiber monitoring module comprising a mounting plate, couplings for receiving plugs of incoming and outgoing glass fibers and at least one coupler module being arranged on the mounting plate, couplers being arranged in the coupler module and being used to split the signals of one incoming glass fiber between at least two outgoing glass fibers at a predeterminable ratio, one outgoing glass fiber transmitting a useful signal and the other glass fiber transmitting a test signal, the glass fibers carrying the test signals being combined in the coupler module to form one multifiber cable, a splitting element being arranged at that end of the multifiber cable which is remote from the coupler module and being used to split the multifiber cable into a number of monofiber cables which corresponds to the number of fibers, plugs being arranged at the ends of said monofiber cables.

Abstract: A method for producing light-scattering structures on flat optical waveguides into which light can be coupled for making the light-scattering structures visible. The light-scattering structures are applied to a surface of the optical waveguide in accordance with a predetermined arrangement prescription. The light-scattering structures are applied directly to the optical waveguide with a non-impact method. The application of the light-scattering structures can occur by imprinting with a computer-controlled, contactless-operating print head or by electro-photographic coating.

Abstract: A coupled waveguide optical microresonator is formed from a plurality of microcylinders coupled together. Each microcylinder includes a resonant waveguide. At least one of the microcylinders is adapted to be positioned adjacent an optical source waveguide for optically coupling light from an optical source waveguide onto the resonant waveguide on the microcylinder. The microcylinders are coupled together at the resonant waveguides, which are mutually coupled. Any coupled fields add coherently with each other.

Abstract: Disclosed is a waveguide type optical device utilizing a nonlinear refractive index change according to a large 3rd order nonlinear optical phenomenon. The waveguide type optical device includes a signal beam waveguide through which a signal beam propagates; and a pump beam waveguide through which a pump beam propagates, wherein the pump beam waveguide is disposed adjacent to the signal beam waveguide so that the pump beam can be coupled to the signal beam waveguide, the signal beam waveguide is made of nonlinear optical materials with large 3rd order nonlinear optical property and the pump beam waveguide is made of linear optical materials, and the wavelength range of the signal beam is different from that of the pump beam. By such a structure, the pump beam is coupled to one arm of the signal beam waveguide, thereby generating a 3rd nonlinear phenomenon on one arm of the waveguide through which the signal beam passes.

Abstract: A polarization compensated planar waveguide branch is disclosed having a planar optical trunk waveguide for transporting a linearly un-polarized optical signal having TE and TM modes. A planar optical branch waveguide, capable of supporting TE and TM modes is optically coupled to the trunk waveguide such that at least a portion of an optical signal propagating within the trunk waveguide will couple into the branch waveguide with an undesired imbalance, having stronger TM mode coupling than TE mode coupling for the at least the portion of the optical signal which couples into the branch waveguide from the trunk waveguide.

Abstract: A variable optical gain control device is capable of amplifying an optical signal while controlling its luminous intensity. The device is made up of optical waveguide paths which are formed on a flat face of a substrate and includes an input directional coupler for combining an input optical signal and a pump laser light; a luminous intensity control portion in the form of a Mach-Zehnder interferometer for controlling the luminous intensity of the optical signal combined with the pump laser light; and an output directional coupler for separating the pump laser light from the resulting optical signal. The luminous intensity control portion is doped with a rare earth element so that the optical signal is amplified by means of the pump laser light, while a heater is applied to one of the optical waveguide paths forming the Mach-Zehnder interferometer to control the luminous intensity of the optical signal.

Abstract: Disclosed are an optical coupler type filter, and a wavelength stabilizing apparatus of a light source using the same.

Abstract: An optical transmission system which permits transmission distance to be prolonged without using repeaters and yet ensures economical, high-quality optical transmission. A branch station performs non-repeated communication with an optical branching point and includes a light pumping section for causing pump light to enter an optical fiber through which a branched, receiving optical signal flows, to perform optical amplification by using the fiber as an amplification medium. An optical branching device includes an optical amplification section and an optical branching section. The optical amplification section redirects the pump light originated from the branch station and propagated through a line to the paired line through which an optical signal transmitted from the branch station flows, to excite an amplification medium inserted in the paired line and doped with active material for optical amplification and thereby amplify power of the optical signal transmitted from the branch station.

Abstract: The present invention relates to all optical choppers for shaping and reshaping. A chopper according to some embodiments of the invention may include a threshold device having an input terminal for receiving an optical input signal and an output terminal for emitting an optical output signal in response to a part of the input signal having intensity above a threshold level of the chopping device, wherein the output signal is narrower than the input signal. In other embodiments the device may include a first splitting device having at least first, second and third terminals, and at least one nonlinear element, wherein the second and third terminals form an optical loop including at least one nonlinear element displaced from the center of the optical loop, wherein the splitting device is arranged to receive an input signal for producing a first output signal that is narrower than the input signal. In further embodiments the optical loop includes at least one more attenuator.

Abstract: An optical demultiplexing device used in an optical monitoring device includes an input port and an output port unit including a plurality of ports, and separates a WDM light of plural channels, which is input from the input port, for each wavelength to output to the output port unit. The output port unit includes a plurality of output port sets each of which includes at least two individual output ports as a set, and crosstalk between adjacent individual output ports in a single output port set is larger than crosstalk between adjacent individual output ports belonging to different output port sets.

Abstract: To provide an optical device whereby the optical characteristics of a lightwave circuit element can be varied with low power consumption. There is provided an optical device comprising a lightwave circuit element having one or plurality of optical waveguides, and also having a refractive index adjusting portion composed of resin located in the one or plurality of optical waveguides and/or in a portion of the area in the one or plurality of optical waveguides. The lightwave circuit element comprises an adjustment-light waveguide for guiding adjustment light that varies the refractive index of the resin, and directing the adjustment light to the adjusting portion.

Abstract: The directional coupler switch is configured by a parallel waveguide including a first region which is subjected to a nonlinear action and a second region which is not subjected to a nonlinear action. A dispersion relationship of the first region is varied due to the nonlinear action to switch over an exit of light entering from an input side to cause the switch to function as an optical switch. A dispersion curve of the first region has: a region of a constant frequency in one of an even mode and an odd mode which are two kinds of eigen modes of the parallel waveguide; and a region in which gradients of the two eigen modes at frequencies belonging to a region other than the region of a constant frequency are substantially equal to each other. The gradients of the two kinds of eigen modes indicate monotone decreasing or monotone increasing.

Abstract: A connector pair formed of a receptacle having an inner cavity about which is arranged a plurality of contact springs each of which is coupled to a corresponding one of a plurality of external contacts, and a plug having a plurality of contact pads upon an outer surface of the plug, and a vertical cavity surface emitting laser (VCSEL) coupled to the plurality of contact pads and at least one optical fiber wherein a portion of the plug occupies a portion of the inner cavity such that at least one of the plurality of contact pads is coupled to at least one of the contact springs.

Abstract: A planar optical isolator is formed within the silicon surface layer of an SOI structure. A forward-directed signal is applied to an input waveguiding section of the isolator and thereafter propagates through a non-reciprocal waveguide coupling region into an output waveguide section. A rearward-directed signal enters via the output waveguide section and is thereafter coupled into the non-reciprocal waveguide structure, where the geometry of the structure functions to couple only a small amount of the reflected signal into the input waveguide section. In one embodiment, the non-reciprocal structure comprises an N-way directional coupler (with one output waveguide, one input waveguide and N?1 isolating waveguides).

Abstract: An optical waveguide used in a WDM optical transmission system are fabricated by the following steps in order to be highly integrated and reduced in size and to have a more preferable design. Namely, a first cladding and a first core are formed on a substrate; at least the first core is etched so as to remain a first waveguiding part for guiding light and non-waveguiding parts, disposed on the both sides of the waveguiding part along a guiding direction of the guiding of light, for guiding no light and in such a manner that two grooves, having varying widths in the guiding direction respectively, are formed between the waveguiding part and each of the non-waveguiding parts; a second cladding is deposited on the remaining first core and the fist cladding; and the second cladding is reflowed by a heat treatment so as to be flattened.

Abstract: Various methods and apparatuses are described for a multiple wavelength light source. The multiple wavelength light source may be located in a central office to supply a first broad band of wavelengths for a one or more passive optical networks. The multiple wavelength light source generates a series of four or more pulses of light in the first broad band of wavelengths. Each pulse of light in that series has a different center wavelength. The series of pulses of light in the first broad band of wavelengths may be repeated at a channel data rate of an optical receiver at a subscriber's location.

Abstract: The present invention describes nanophotonic materials and devices for both classical and quantum optical signal processing, transmission, amplification, and generation of light, which are based on a set of quantum systems having a discrete energy levels, such as atoms, molecules, or quantum dots, embedded in a frequency bandgap medium, such as artificial photonic crystals (photonic bandgap materials) or natural frequency dispersive media, such as ionic crystals, molecular crystals, or semiconductors, exhibiting a frequency (photonic) bandgap for propagating electromagnetic modes coupled to optical transitions in the quantum systems. If the frequency of one of optical transitions, called the working transition, lies inside the frequency bandgap of the medium, then spontaneous decay of the working transition into propagating photon modes is completely suppressed.

Abstract: Provided is a millimeter wave oscillator for generating a high frequency signal required in wireless communication. The millimeter wave oscillator uses an overwritten fiber Bragg grating and a light detector such that two wavelengths in a certain phase relationship are produced to generate a signal of a millimeter wave band with a high frequency, whereby a light source is readily obtained without signal processing for phase lock.