Abstract: An optical coupling structure includes a PQR hole emitter having a PQR hole, and an optical fiber whose one side is tapered into the PQR hole. An index-matching solution such as a photo-resist or a photo-resist diluted solution is injected into the PQR hole to adhere the optical fiber and the PQR hole.

Abstract: A wavelength independent multi-section optical coupler having at least three optical couplers, and at least two differential phase cells. Each optical coupler has two waveguides forming a coupling region having a net coupling value. The coupling value for each coupling region of the at least three optical couplers is different than the coupling values of the other two coupling regions. Each differential phase cell connects adjacent ones of said optical couplers. Each differential phase cell causes a differential phase shift in light signals traversing between the optical couplers, wherein the differential phase shifts of the differential phase cells, and the coupling value for each coupling region are chosen so as to minimize wavelength, and fabrication sensitivity of said wavelength independent multi-section optical coupler for a designed power splitting ratio.

Abstract: In a dispersion compensation element 10X, a plurality of regions (I) and (II) mutually different in radius and interval of holes 24 are set, and voltages applied at electrodes 30A and 30B are controlled in respective regions (I) and (II) to make variable the sign and the absolute value of chromatic dispersion compensation. In a dispersion compensation system formed by using the dispersion compensation element 10X, an optical pulse picked up from an optical fiber transmission line is monitored, and the amount of voltage applied at the dispersion compensation element 10X is controlled based on its chromatic dispersion information to perform dispersion compensation of the optical pulse propagated through the optical fiber transmission line. Alternatively, dispersion compensation can be performed by varying the carrier density of the waveguide by applying a voltage to change the refractive index of the waveguide.

Abstract: A dispersion compensator is applicable to a WDM optical transmission system and features low loss, wideband usage, and minimum ripple. The dispersion compensator is constructed so that the light emitted from a collimator will be reflected from an etalon of a 100% single-side reflectance by arranging the etalon and a mirror in parallel or with a slight angle and then enter another collimator. Elements for achieving variable dispersion compensation by changing temperature using a heater, for example, are also provided. In addition, these dispersion compensating elements are provided in multi-stage form and the angle of the mirror and the reflectance of the etalon are optimized. Thus, it becomes possible to realize a dispersion compensator applicable to a WDM optical transmission system and featuring low loss, wideband usage, and minimum ripple.

Abstract: An optical receiver includes a first light receiving element to convert an optical signal to an electric signal and to output the electric signal from one end. A light receiving element row is connected to the other end of the first light receiving element to supply electric power to the first light receiving element. The light receiving element row includes a plurality of second light receiving elements connected in series.

Abstract: Various embodiments of the present invention are directed to photonically-coupled quantum dot systems. In one embodiment of the present invention, a photonic device comprises a top layer, a bottom layer, and a transmission layer positioned between the top layer and the bottom layer and configured to transmit electromagnetic radiation. The photonic devices may also include at least one quantum system embedded within the transmission layer. The at least one quantum system can be positioned to receive electromagnetic radiation and configured to emit electromagnetic radiation that propagates within the transmission layer.

Abstract: A method for separating the orthogonal polarization components of an incident optical signal into two spatially separated output ports is described. The method comprises a Mach-Zehnder interferometer where one of the two branches has a section of waveguide that exhibits form-birefringence. This integrated optic Polarization Beam Splitter (PBS) is broadband, has high extinction ratio, and has characteristics that are tunable.

Abstract: In the present invention, a method of controlling a tuneable optical dispersion compensating device to act on an optical signal by automatically controlling a plurality of dispersion control settings of the device in a systematic way using feedback, thereby to adapt freely the optical group delay for the optical signal within a predetermined wavelength range including that of the optical signal.

Abstract: There is provided a fiber optic transmission system, comprising: an optical signal source adapted to produce a frequency modulated signal; and a multi-ring resonator optical spectrum reshaper (OSR) adapted to convert the frequency modulated signal into a substantially amplitude modulated signal. And there is provided a method for transmitting an optical signal through a fiber comprising: producing a frequency modulated signal; passing the frequency modulated signal through a multi-ring resonator optical spectrum reshaper (OSR) so as to convert the frequency modulated signal into a substantially amplitude modulated signal; and passing the substantially amplitude modulated signal into the fiber.

Abstract: A method and apparatus for monitoring one or more environmental parameters using interferometric sensor(s), a cross-correlator, a two-dimensional photosensitive array and optical focusing means are described. The method and apparatus allows for near simultaneous monitoring of the parameter(s) of interest.

Abstract: A composite evanescent waveguide can include a first structured dielectric layer and a second dielectric material oriented adjacent one another to form a wave propagation interface between the first structured dielectric layer and second dielectric material. Each of the first structured dielectric layer and second dielectric material are formed of materials such that the wave propagation interface can be capable of propagating an all-evanescent surface wave. The resulting propagating surface waves tend to have low losses and can be suitable for optical communications, surface analysis, sensors, and a variety of other applications.

Abstract: A system and methods for routing optical signals are disclosed. The system includes a first large core hollow waveguide having a reflective coating covering an interior of the waveguide and configured to guide a substantially collimated multi-mode coherent light beam. A second large core hollow waveguide with an interior reflective coating is coupled to the first waveguide with a coupling device. The coupling device is configured to redirect at least a portion of the coherent light beam from the first to the second waveguides through an optical path that is sufficiently short that a beam walk-off of the coherent light through the coupling device is less than half a width of the first large core hollow waveguide.

Abstract: A wide passband optical interleaver includes a first optical splitter, having a first output terminal and a second output terminal. A first optical route is coupled to the first output terminal. A second optical route is coupled to the second output terminal. A delay is coupled on the second optical route. A second optical splitter having two input terminals is receiving the first optical route and the second optical route. A plurality of optical filter respectively having transmission coefficients ?i is coupled to the first optical route and the second optical route. The transmission coefficients ?i are determined by satisfying a desired quantity of effective group delay ratio T, defined as T = ? i ? S i ? 1 - ? i 1 + ? i , where ? ? S i ? ? is + 1 ? ? or - 1. where Si is +1 or ?1.

Abstract: An optical waveguide propagates a laser beam. Main diffraction grating and sub-diffraction grating couple light propagating in the optical waveguide. The main diffraction grating and the sub-diffraction grating couple the light in such a manner that propagation in a second order transverse mode of the light propagating in the optical waveguide when both the main diffraction grating and the sub-diffraction grating are disposed, is suppressed more than propagation in the second order transverse mode of the light propagating in the optical waveguide when only the main diffraction grating is disposed.

Abstract: Aspects of the disclosure are directed to optical microcavities and emitters that are spectrally aligned in an arrangement having an array of such microcavity-emitter combinations. The spectral alignment can be selective, in that a portion of the array of microcavity-emitter combinations, or a single microcavity-emitter combination, can be individually spectrally aligned. In specific examples, light is coupled within a semiconductor device having wavelength-dependent structures and optical cavities optically couple to the wavelength-dependent structures. One of the optical cavities and a wavelength-dependent structure are spectrally aligned, independent of another of the optical cavities.

Abstract: A sensor apparatus includes a laser optically coupled to a photonic crystal structure configured to provide an evanescent field through a sensed medium region such that the photonic crystal structure functions as a cavity/resonator for the laser.

Abstract: A technique for suppressing stimulated Brillouin scattering (SBS) in fibers intended to handle high powers. A fiber is embedded in an elongated embedding material to form an embedded fiber structure. The embedded fiber structure is formed either as a cantilevered beam or as one or more turns around a circular or elliptical path, and then the entire structure is deformed to apply a desired strain that varies along the fiber length and results in suppression of SBS. In one embodiment, the embedded fiber structure is deformed by applying lateral and generally diametric force across the turns of the structure, resulting in changes to its curvature. In another embodiment the embedded fiber structure initially has a helical shape, which is deformed by stretching or twisting to change its radius. In either embodiment, a desired strain profile is obtained by selecting the position of the fiber with respect to a neutral axis.

Abstract: The present invention includes apparatus and method of a variable step size dithering control algorithm for polarization mode dispersion controllers (PMDCs). The dithering step size of the PCs is adjusted according to the feedback signal including degree of polarization (DOP).

Abstract: One embodiment of the present invention includes a plurality of first optical elements and a second optical element optically coupled to one another in cascaded fashion. Each first optical element has a group delay response characterized by a first period such that only one group delay peak occurs within a first channel. By contrast, the second optical element has a group delay response characterized by a second period, which is less than the first period, such that more than one group delay peak occurs within the first channel. The preferred embodiment uses cascaded GT etalons to provide the desired group delay responses. One advantage of the present invention is that the passband of the dispersion compensator is increased relative to prior art designs without increasing insertion losses. Alternatively, the same passband common in prior art designs may be achieved with fewer GT etalons, thereby reducing insertion losses.

Abstract: The distance between an optical diffraction device and a focusing lens, and the coefficient of the focal length change of the focusing lens, are adjusted based on the calculation expression of wavelength identification errors in light of temperature change of a member making up light receiving means (e.g., PD array), thereby performing correction of wavelength identification errors, whereby optical wavelength identification can be performed with high precision even when the temperature changes.

Abstract: An optical switch, comprising an optical resonator, a first input optical waveguide optically coupled to the optical resonator for guiding a first optical signal to the optical resonator; a second input optical waveguide optically coupled to the optical resonator for guiding a second optical signal to the optical resonator; and an output optical waveguide optically coupled to the optical resonator for guiding a third optical signal from the optical resonator, wherein the optical resonator has a first region and at least one separate second region made of different materials, at least one of which is non-linear to cause different resonance frequencies of the optical resonator for different intensities of light.

Abstract: A polarization maintaining optical device may include a polarization maintaining optical array. The device may also include a microlens array to receive light from the polarization maintaining optical array. In another embodiment of the present invention, the device may also include two microlens arrays, two polarization maintaining optical arrays, and an arrayed beam steering device. The microlens arrays, polarization maintaining optical arrays, and the beam steering device may be optically coupled.

Abstract: An optical element, an optical module holder including the optical element, an optical module, and an optical connector are provided that can suppress, at a low cost, a change in an intensity of a light that is emitted from a photoelectric conversion:element and coupled to an end section of an optical transmission path, the change accompanying a change in an usage environment temperature, perform a stable optical communication having a superior heat resistance property at a low cost, and can achieve size reduction and improved versatility. A diffraction grating 17 is formed to suppress, to within a predetermined allowable limit, a coupled light temperature characteristic indicating a change in an intensity of a light of a specific diffractive order that is coupled to an end section of an optical transmission line 12, the change accompanying a change in a usage environment temperature of a photoelectric converter 8.

Abstract: An optical receiving apparatus sets, efficiently and optimally, a delay interferometer and a variable wavelength dispersion compensator in the apparatus.

Abstract: Apparatuses and methods for modulating electromagnetic radiation are disclosed. A plasmon waveguide including an array of metallic nanoparticles disposed on a dielectric substrate is provided. The plasmon waveguide is disposed on a MEMS structure. An electromagnetic radiation signal is applied to a tapered fiber disposed proximate the MEMS structure. The intensity of the electromagnetic radiation signal passing through the tapered fiber is modified by displacing a deformable member of the MEMS structure to modify a distance between the plasmon waveguide and the tapered fiber such that an evanescent field of the tapered fiber causes a plasmon resonance in the plasmon waveguide.

Abstract: A microstructure optical adapter or tip according to the present disclosure may incorporate precision micro structure optical components engaging the input or output end of light energy delivery devices for customized light delivery of the light energy. The incorporation of precision micro structure optical components in injection molded plastic or glass parts will allow for inexpensive modification of the output light while also serving to protect the end of the illumination device. The micro structure optical components may also be incorporated in an adapter to tailor the light energy to the subsequent device.

Abstract: Dispersion compensation for an optical signal having a first frequency range is described. The optical signal is applied to a dispersion compensating material having a negatively refracting behavior within the first frequency range. The dispersion compensating material is tuned by application of a control signal that varies at least one characteristic of the dispersion compensating material associated with the negatively refracting behavior.

Abstract: In a first aspect, the present invention comprises an optical filter comprising a fiber having a core and a cladding and a light-absorbing coating applied onto a portion of the fiber cladding, the coating attenuating loosely bound cladding modes. In another aspect, the invention comprises a fiber amplifier apparatus comprising fibers for delivering pump laser light and for monitoring signal light and at least one photodetector optically coupled to a monitoring fiber, wherein either an optical filter is disposed between a monitoring fiber and a photodetector or at least one of the fibers has a core and a cladding and a light-absorbing coating applied onto a portion of the fiber cladding. A method in accordance with the present invention includes providing an optical amplifier having fibers for delivering pump laser light and for monitoring signal light, and applying a light-absorbing coating onto a portion of one of said fibers.

Abstract: The invention pertains to optical fiber transmission systems, and is particularly relevant to transmission of large volumes of data over long distances at high rates. An improved apparatus achieving precise dispersion compensation in a fiber span is disclosed. In particular, the invention teaches a configurable dispersion compensation trimmer with automatic detection of configuration.

Abstract: Various methods, systems, and apparatuses is described in which a passive-opticalnetwork includes a first multiplexer/demultiplexer, a second multiplexer/demultiplexer, a wavelength tracking component, and a transmission wavelength controller. The first multiplexer/demultiplexer is located in a first location. The second multiplexer/demultiplexer is located in a second location remote from the first location. The wavelength tracking component determines the difference between the transmission band of wavelengths of the first multiplexer/demultiplexer and the second multiplexer/demultiplexer to provide a control signal to match the transmission band of wavelengths of the first multiplexer/demultiplexer and the second multiplexer/demultiplexer. The transmission wavelength controller alters an operating parameter of the first multiplexer/demultiplexer based on the control signal to control the transmission band of wavelengths of the first multiplexer/demultiplexer.

Abstract: Methods and apparatus for reducing a thermal load on an optical head are described. Waste light is captured at one or more locations in the optical head and directed to a location that is thermally isolated from the one or more locations in the optical head using or more optical fibers.

Abstract: Embodiments of the present invention provide a current sensing device. The current sensing device includes, inter alia, a three-by-three (3×3) optical coupler made of polarization-maintaining (PM) fibers and thus being a PM fiber coupler; a light source and at least one photon-detector connected to a first side of the 3×3 PM fiber coupler; and a fiber coil connected to a second side of the 3×3 PM fiber coupler. The 3×3 PM fiber coupler is adapted to split an input light from the light source into first and second optical signals while maintaining their respective polarization directions; and is adapted to cause coherent interference of third and fourth optical signals, related respectively to the first and second optical signals and received from the fiber coil.

Abstract: An optical device includes a waveguide and a microdisk that is optically coupled to the waveguide. The gap between the microdisk and the waveguide is between 0.3 microns and 0.7 microns. The diameter of the microdisk is between 15 microns and 50 microns. The quality factor of the microdisk is at least 105. The microdisk is tuned optoelectrically or piezoelectrically.

Abstract: Methods and systems for PMD compensation in an optical communication system are implemented by transmitting multiple optical signals through a common optical conduit to an optical compensator that adjustably rotates the polarization states of the multiple optical signals and transmits the rotated optical signals to an optical receiver. The receiver, upon sensing an excessive error condition, commands the optical compensator to change the polarization state of rotation, which changes the PMD profile of the received optical signals.

Abstract: Method and apparatus are provided for compensation of an RF link between a transmitter and amplifier of a communication system. The apparatus comprises a signal source coupled to the transmitter for providing an RF test signal of a first magnitude to the RF link, a test signal measuring apparatus at the RF input of the amplifier for measuring a second magnitude of the test signal reaching the RF input of the amplifier through the RF link, and an electronically adjustable attenuator serially coupled with the RF link and responsive to differences between the first and second magnitudes so as to provide attenuation in an RF communication signal passing into the amplifier from the RF link such that the sum of RF signal loss in the link and the attenuator has a predetermined value.

Abstract: A photonic crystal structure is provided the optical characteristics of which vary periodically in at least one direction, wherein the base material of the photonic crystal structure is formed of a dielectric material, a region containing at least one of molecules, atoms and ions different from the constituent element of the base material is provided in the base material, and the region is arranged in the base material so that the density of one of the molecules, atoms and ions varies periodically in the one direction.

Abstract: Multi-loop opto-electronic oscillators using tunable RF or microwave filters that achieve signal filtering in RF or microwave frequencies by optical filtering and signal tuning by optical tuning.

Abstract: The invention pertains to optical fiber transmission systems, and is particularly relevant to transmission of large volumes of data over long distances at high rates. An improved apparatus achieving precise dispersion compensation in a fiber span is disclosed. In particular, the invention teaches a configurable dispersion compensation trimmer with automatic detection of configuration.

Abstract: A method of filtering optical signals (300) utilizing an optical fiber (100A-100D). The method of filtering optical signals (300) includes the steps (304) selecting an optical fiber (100A-100D) coupled to a source of optical signals, (306) disposing a core (102) in the bore (103) of the optical fiber (100A-100D) formed of a core material (105), (308) selecting a core material (105) to provide a waveguide within the optical fiber (100A-100D), (310) disposing an optical grating (114-1) in a first optical cladding layer (104) disposed about the core (102), (312) propagating an optical signal within the optical fiber (100A-100D) guided substantially within the core (102), (314) modifying a propagation path of selected wavelengths comprising said optical signal with the optical grating (114-1), and (316) determining selected wavelengths for which the propagation path is modified by selectively varying an energetic stimulus to the core (102) thereby tuning the waveguide.

Abstract: A group delay compensation equalizer is disclosed that employs a single channel four-port WDM device for compensating the group delay experienced by a plurality of wavelengths transmitted over different paths. The transmission differential between two wavelengths is compensated by transmitting the two wavelengths through two different paths where the fiber length in reflecting the second wavelength is equal to the transmission time difference between the two wavelengths. The single channel four-port group delay equalizer effectively provides a unidirectional signal flow, as compared to the conventional equalizer that transmits optical signals bi-directionally. The present invention reduces the cost of a group delay equalizer by simplifying the use of multiple three-port WDM devices into a single channel four-port WDM device.

Abstract: An embedded flight sensor system having a laser and one or more flight sensors in optical communication with the laser plus a data processing device in optical communication with the flight sensors. The flight sensors may be laser based optical components such as a fiber Bragg grating in combination with an optical detector, a spectroscopy grating and detector or an optical detector associated with catch optics. The parameters sensed by the flight sensors may be used to determine any flight parameter. Representative flight parameters include but are not limited to an airframe or external surface temperature, airstream velocity, combustion zone temperature, engine inlet temperature, a gas concentration or a shock front position.

Abstract: An optical transmission system (1) alters quantity of incident light by reflecting an optical signal by a micro mirror (11) to enter an optical fiber (13) and by controlling an angle of the micro mirror (11), so that attenuation of the optical signal is controlled. An optical filter (14) is disposed between the micro mirror (11) and the optical fiber (13), for correcting a relationship between a control angle or control voltage of the micro mirror (11) and attenuation of the optical signal to be close to a linear relationship.

Abstract: An optical reader system and method are described herein that directs a non-coherent light towards a biosensor, collects the non-coherent light which is reflected (or transmitted) from (or through) the biosensor, and then angularly filters the collected non-coherent light to obtain a narrow spectral response which can be analyzed to determine if a biological substance is located on the biosensor or if a biomolecular event took place on the biosensor.

Abstract: A tunable optical dispersion compensator includes an optical input port, an input variable optical coupler, at least two optical dispersion paths, an output variable optical coupler, and an optical output port. The input variable optical coupler is coupled to selectively split portions of the optical signal received from the optical input port into each of its output ports. The optical dispersion paths are each coupled to one of the output ports of the input variable optical coupler to impart dispersion compensation to each of the split portions of the optical signal. An output variable optical coupler selectively combines the split portions of the optical signal received on its input ports from the optical dispersion paths. The optical output port is coupled to the output variable optical coupler to output a dispersion compensated optical signal.

Abstract: An optical splitter/coupler has: a multimode waveguide having an electrooptic effect, and propagating light in a multimode; one incident waveguide propagating light in a single mode, and inputting the light to the multimode waveguide; one pair of emitting waveguides guiding-out, in a single mode, lights which have propagated-in through the multimode waveguide; at least one pair of individual electrodes provided so as to be positioned in vicinities of respective side edges on one surface of the multimode waveguide; and a ground electrode provided on another surface, wherein the multimode waveguide has a length such that 3(n+1) bright spots arise at a central portion and at both side edge portions due to incident light, the individual electrodes are provided at positions corresponding to an upstream-most one pair of the bright spots, and the emitting waveguides are connected to positions corresponding to a downstream-most one pair of the bright spots.

Abstract: In an optical communication link a first node (30) with transmission means (50) and a second node with receiving means (40) are connected by at least two optical fiber transmission paths (100,200). One path serves as the working path, while the remaining path or paths serve as protection paths. The transmission means in the first node is connected to an optical signal power splitter (60) which couples the signal power from the transmitting means unequally into the different transmission paths. This uneven coupling of signal power imposes greater losses in one path than in the other or others. By arranging the splitter to couple a higher proportion of the transmitted optical power into the path that has the highest inherent losses the additional loss imposed on this path is reduced. Thus the maximum path loss between any two nodes can be minimized. This in turn means that the link length and also the size of the network is virtually unaffected by using the same transmitter.

Abstract: A resonator structure includes an input waveguide and an output waveguide. In one embodiment, the resonator structure also includes at least one resonator that couples the input waveguide to the output waveguide and a directional coupler that optically couples the input waveguide to the output waveguide. In another embodiment, the resonator structure includes a plurality of ring resonators that couple the input waveguide to the output waveguide. The plurality of ring resonators include a sequence of ring resonators that form a coupling loop. Each ring resonator in the sequence is coupled to at least two other ring resonators in the sequence and the first ring resonator in the sequence is coupled to the last ring resonator in the sequence so as to form the coupling loop.

Abstract: In an optical communications link, an optical system including: at least a first input port for delivering an optical signal travelling in the communications link, the optical signal including a plurality of wavelength channels, the channels being utilized for carrying optical information over an optical data link; a dispersive element for spatially separating the wavelength channels; an active optical-phase element; and a plurality of optical manipulation elements for directing the spatially separated channels between the dispersive element and the optical phase element wherein, the optical phase element independently modifies the phase of predetermined ones of the wavelength channel in a predetermined and decoupled manner for substantial compensation of signal degradation effects imparted to the wavelength channels by said communications link.

Abstract: Various aspects of the present invention are directed to a nanowire configured to couple electromagnetic radiation to a selected guided wave and devices incorporating such nanowires. In one aspect of the present invention, a nanowire structure includes a substrate and at least one nanowire attached to the substrate. A diameter, composition, or both may vary generally periodically along a length of the at least one nanowire. A coating may cover at least part of a circumferential surface of the at least one nanowire. The nanowire structure may be incorporated in a device including at least one optical-to-electrical converter operable to convert a guided wave propagating along the length of the at least one nanowire, at least in part responsive to irradiation, to an electrical signal. Other aspects of the present invention are directed to methods of fabricating nanowires structured to support guided waves.

Abstract: Fiber lasers for producing Band I wavelengths include a laser cavity having an optical fiber with specific parameters in length and thickness and doping concentration, and having high reflectivities. Examples show the feasibility of producing such fiber lasers. Fiber lasers for producing Band IV wavelengths include a depolarized laser oscillator, at least one amplifier and a polarizer. Depolarized laser oscillator is an inherently depolarized CW laser, or a depolarized laser diode, which is depolarized by a depolarizer. Additional fiber lasers in accordance with embodiments of the present invention include a double clad active optical fiber having a pump power entry point for sending pump energy through the active optical fiber in a first direction, and a loop portion at a second end of the fiber for sending pump energy through the active optical fiber in a second direction which is opposite to the first direction.