Abstract: An electromagnetic signal processing system (10) comprises a plurality of optical fiber arrays (11, 12, 13, 14, 15 and 16) each having a cluster of optical fibers with their one ends (40) oriented to receive electromagnetic radiation from free-space, or to transmit electromagnetic radiation into free-space. Received electromagnetic radiation passes through respective array outputs (21, 22, 23, 24, 25 and 26) and optical delays (50, 51; 55, 56; 65) to the input (68) of a signal detector (69). Transmitted electromagnetic radiation from sources (71, 72) passes through optical delays (50, 51; 55, 56) to array inputs (21, 22, 23, 24, 25 and 26) so that the one ends (40) of the optical fibers transmit the electromagnetic radiation into free-space.

Abstract: A dispersion compensator is provided that includes an input port 102 for receiving a WDM optical signal and a dispersion compensating element 110 coupled to the input port for substantially compensating the WDM optical signal for dispersion that has accumulated along an external transmission path. The dispersion compensator also includes an output port 104 for directing the dispersion compensated WDM optical signal to an external element and a dynamic power controller 106, 108, 112, 114, 116 for maintaining a total power of the WDM signal below a prescribed level prior to receipt of the WDM optical signal by the dispersion compensating element.

Abstract: This application describes coupled and non-coupled opto-electronic oscillators with enhanced performance. Coupled OEOs implement a dispersion compensation mechanism to reduce dispersion-induced optical loss, a polarization control mechanism to reduce polarization-dependent optical loss, or a combination of the dispersion compensation mechanism and the polarization control mechanism to enhance the oscillator performance.

Abstract: An optical multiplexer includes a substrate into which are integrated a polarization rotator and a polarization coupler. The polarization coupler and the polarization rotator are in optical communication with each other.

Abstract: Devices and techniques for filtering RF or microwave frequencies by optical filtering using a tunable optical filter.

Abstract: Effects of diffraction of a spectral beam from an edge of the micromirrors are reduced in order to optimize the passband in a wavelength selective switch. The effects of diffraction on the pass band may be reduced by using rotation of the micromirror about both the attenuation axis and the switching axis to achieve the desired level of attenuation. Peak coupling can be attained by dithering the micromirror about a dither axis that is tangent to a contour of constant attenuation using simultaneous rotation about the switching and attenuation axes. A power level of a spectral channel may be attenuated by rotating the channel micromirror with respect to an effective attenuation axis that is non-orthogonal to the dither axis through a combination of rotations about the switching axis and the attenuation axis.

Abstract: The present invention relates to a device for use in a fiber optic system that may be a communication system, a sensing system or other system using guided-wave optical components. Reducing the number of lenses required to couple the waveguides and the free-space paths in the device offers the dual advantages of a reduced component count and simplified alignment. In an exemplary device having a first and second waveguides, a birefringent optical system defines bi-directional, polarization-dependent free-space paths. One of the bidirectional, polarization-dependent, free-space paths couples at least the first waveguide to the second waveguide. The birefringent optical system includes at least one prism for bending one of the polarization-dependent paths in a clockwise direction and one of the polarization-dependent paths in a counterclockwise direction.

Abstract: An arrangement for optical fibre communications, for used, e.g., in millimetre (MM) fibre transmission systems includes: a source (1) of optical radiation defining an offset launch path of optical radiation (R) into an optical fibre (F), and at least one active element (3,4; 6; 7) actuatable to selectively vary said offset launch path in order to achieve an adjustable offset launch of said optical radiations (R) into said optical fibre (F).

Abstract: Provided is a double waveguide electroabsorption modulator, in which two spot size converters are integrated between first and second optical waveguides, thereby reducing an insertion loss between an optical fiber and an optical modulator while favorably operating even in high input optical power. Therefore, the electroabsorption modulator can stably operate in higher input optical power while reducing an optical coupling loss and an optical confinement factor (OCF).

Abstract: An integrated optical add/drop device having switching function for use in wavelength division multiplexing optical communication systems, has first and second optical couplers between which first and second interferometric arms of an interferometer are extended. The integrated optical add/drop device has an optical filter having first and second input ports connected to first portions of the first and second interferometric arms and first and second output ports connected to second portions of the first and second interferometric arms. The optical filter acts as a selective switch exchanger for exchanging between one interferometric arm and the other at least one of a plurality of optical signals S (?1), S (?2), . . . , S (?n), received at its input ports and for transmitting the remaining optical signals through its output ports in the first and second interferometric arms.

Abstract: The invention provides a wavelength selective optical device in which a light emitted from an end surface of a first optical fiber that propagates optical signals with a plurality of multiplexed wavelengths is incident on a first end surface of a first graded index rod lens, then a parallel light beam emitted from a second end surface of the first graded index rod lens is incident on an optical filter arranged to face to the second end surface of the first graded index rod lens, and then a light reflected by the optical filter is incident again on the second end surface of the first graded index rod lens so as to couple to a second optical fiber arranged on a first end surface side of the first graded index rod lens, wherein a refractive index distribution constant of the first graded index rod lens is set such that a center wavelength of the light reflected by the optical filter is positioned within a desired range.

Abstract: An optical fiber comprises core and cladding regions configured to guide the propagation of light (or radiation) in the core region. The cladding region includes a periodic structure configured to produce light guiding by bandgap confinement. In order to suppress higher order odes (HOMs) in the core region, the cladding region includes at least one perturbation region configured so that a mode of the cladding region is resonant with a HOM of the core region. In a preferred embodiment of my invention, the perturbation region is configured so that the fundamental mode of the cladding region is resonant with a HOM of the core region.

Abstract: Provided are an apparatus and a method for reducing a signal noise of an OCDMA receiver and an OCDMA receiver and method. The includes: a clock recovery unit extracting sine wave clock from an output signal of an OCDMA decoder including an MAI (multiple access interference) noise; a time gating unit separating an auto-correlation peak signal and the MAI noise from the output signal of the OCDMA decoder using the sine wave clock; and an optical interferometer removing an SI (signal interference) noise remaining in the auto-correlation peak signal.

Abstract: The use of bulge-like microcavities in microcavity sensors provides advantages in alignment and reproducibility in manufacturing. Arrays of bulge-like microcavities may be used with multiple waveguides. In addition, the bulge-like microcavity may be formed with at least an outer layer made of a polymer material, and may be made entirely from polymer material. This facilitates manufacturing in that the microcavity may be molded, and may also be reproducibly molded in an array configuration.

Abstract: Effects of diffraction of a spectral beam from an edge of the micromirrors are reduced in order to optimize the passband in a wavelength selective switch. The effects of diffraction on the pass band may be reduced by appropriate modification of the edges of the micromirrors, by modification of the input and/or output ports to allow for attenuation by rotation of the micromirror about the switching axis, by using rotation of the micromirror about both the attenuation axis and the switching axis to achieve the desired level of attenuation, by inserting an aperture at a focal plane or external to the device to reduce the magnitude of the micromirror edge diffraction transmitted to any or all output ports, or by appropriate filtering of angular frequencies with a diffraction grating used to separate a multi-channel optical signal into constituent spectral beams.

Abstract: A bandpass filter, and associated method, are provided for an optical data signal, wherein the transmission curve of the bandpass filter has a passband at a mid-frequency for a particular bandwidth. The transmission curve has an attenuation range which covers the mid-frequency. This makes it possible to effectively increase the sensitivity of optical reception, particularly at a high data rate. When use is made of a number of bandpass filters having passbands which are arranged next to one another spectrally, such arrangement is highly suitable for a WDM signal.

Abstract: A system to remove cladding light from an optical fiber that includes a core and a cladding that surrounds the core. A volume of an index-matching material contacts an exterior surface of the cladding along a contact length of the optical fiber. The index-matching material has a refractive index that substantially matches a refractive index of the cladding at a predetermined clamping temperature and has a refractive index with a negative temperature coefficient, such that the index matching material distributively removes light from the cladding along the contact length based on the temperature of the index matching material that contacts the cladding.

Abstract: An apparatus and method for generating a wavelength-tunable short pulse that can generate wavelength-tunable short pulsed light in the visible-light wavelength band are provided. When ultrashort pulsed light is introduced into an optical fiber (3), a wavelength-tunable ultrashort soliton pulse is generated by a nonlinear optical effect through the soliton effect and Raman scattering. When the soliton pulse has a short duration and high peak intensity, a third harmonic having one-third of the wavelength of the soliton pulsed light is generated by a third nonlinear optical effect. This third harmonic has a short wavelength in the visible light band.

Abstract: A device for crossing optical beams. At least a first input optical waveguide is directed along a first axis, a second optical waveguide is directed along a second axis inclined with respect to the first axis, and a photonic crystal having a regular periodicity in an optical crossing region at the intersection of said first and second axis has, opposite the first and second input waveguides, a first and a second output waveguide to provide for exit beams.

Abstract: An optical reader system is described herein which has a single mode (SM) optical fiber launch/receive system that uses one or more SM optical fibers to interrogate a biosensor and does not use multimode (MM) optical fibers to interrogate the biosensor. The use of the SM optical fiber launch/receive system effectively reduces angular sensitivity, reduces unwanted system reflections, improves overall angular tolerance, and improves resonant peak reflectivity and resonant peak width. Two specific embodiments of the SM optical fiber launch/receive system are described herein which include: (1) a dual fiber collimator launch/receive system; and (2) a single fiber launch/receive system that interrogates the biosensor at a normal incidence.

Abstract: The field of the invention is that of the semiconductor optical devices used in particular for fibre-optic telecommunications. To function efficiently, a certain number of semiconductor devices require the use of light polarized in a given polarization state. When knowledge of the polarization the state is lost, the optical element according to the invention makes it possible to polarize the light again in a known polarization state. By using two of these elements in combination with a coupler, it is possible to produce a device which fulfils the same function as a polarization splitter. This optical assembly delivers two output signals whose polarization states are the projections of the initial polarization onto two orthogonal axes. The main advantage of these devices is that they are produced using polarization rotators based on photonic crystals, and they can consequently be integrated easily into semiconductor devices, which the use of discrete polarizers does not allow.

Abstract: A reconfigurable optical add/drop multiplexer (ROADM) includes a first optical dynamic gain equalization filter (DGEF) having a first input for receiving an initial wavelength division multiplexed (WDM) signal, a first output for sending a phase shifted WDM signal, and a second output connected to a demultiplexer for demultiplexing a WDM drop signal thereby producing a plurality of drop channels. A second DGEF having a first input for receiving the phase shifted WDM signal, a second input connected to a multiplexer, for multiplexing a plurality of add channels to produce thereby a wavelength division multiplexed (WDM) add signal, and an output for sending a second adjusted WDM signal. The ROADM allows for the channels from the initial WDM signal to be dropped, added and equalized.

Abstract: This application describes techniques for optical multiplexing and demultiplexing in optical communication systems based on polarization multiplexing of different signal channels.

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: It is a collimator adapted to convert divergent light beams outputted from an optical fiber bundle to parallel light beams through a collimator lens. A large diameter optical fiber is disposed between an optical fiber bundle, which is a bundle of a large number of multimode optical fibers and serves as one optical transmission path, and a collimator lens. A cross-section of the core of the large diameter optical fiber is larger than a range in which the cores of the optical fibers of the optical fiber bundle are present. Also, a group of divergent light beams outputted from the optical fibers of the optical fiber bundle is converted by the large diameter optical fiber to one light beam.

Abstract: There are provided a power supply device for an optical functional component that supplies power to the optical functional component with reliability for a long term and enables easy exchange of the optical functional component, and an optical functional module having such a power supply device, where the power supply device is provided with a reception electrode 104, a power supply electrode 107-1 that supplies power to the reception electrode 104 while holding tight the reception electrode 104 on its side faces and thereby holding an optical functional component 105-1 detachably, and a protecting member 108 that is made of an insulating material and surrounds the power supply electrode 107-1 to prevent current leaks, and the power supply electrode 107-1 is comprised of two bent metallic members (107-1a and 107-1B) which are in intimate contact with the reception electrode 104 by elasticity.

Abstract: Hierarchical hybrid optical networking is based on balancing cost and performance of optical networks by providing transparent (optical) switching of subsets of wavelengths in addition to opaque (electrical) switching of individual light paths. Effective use of wavelength-subset switching requires aggregating and deaggregating wavelength subsets in a simple, cost-effective manner. Non-uniform wavebands are introduced and analyzed their performance advantage as compared with uniform wavebands. Also proposed are several architectural options for a hierarchical hybrid optical cross-connect system that combines non-uniform wavebands and improved utilization of OEO ports.

Abstract: A bidirectional optical transceiver is disclosed. The transceiver comprises an optical fiber which is adapted to input/output optical signals and has a slant surface polished with an angle, a substrate having a groove formed on its upper portion to position the optical fiber therein, a wavelength distributor filter inserted into the substrate with a slant substantially matching the angle in the optical fiber, a photodiode positioned on the substrate to receive optical signals, a TO-Can having a laser diode that is positioned in a location opposite to the optical fiber to transmit optical signals, and a single housing adapted to mount the optical fiber, the substrate, and the TO-Can thereon.

Abstract: An apparatus and method are provided for manipulating light beams propagated through PLCs in free space. Light beams propagated in through an input/output waveguide of a PLC are propagated through a waveguide array to generate a phased array output at an edge facet of the PLC. The phased array output at the edge facet is spatially Fourier transformed by a lens in free space, generating a spectrally resolved image at the back focal plane of the lens. The spectrally resolved image is reflected, at least in part, by a reflector device and coupled into a desired waveguide array of a PLC to produce a desired output.

Abstract: A multi-port planar evanescent coupler having N inputs and M outputs, where both N and M are each no less than three, formed of combinations of at least one of at least one planar evanescent 2×2 coupler and at least one planar evanescent 3×3 coupler subunits, with phase shifting segments in selected waveguides disposed between the planar evanescent coupler subunits. The multi-port planar evanescent coupler can be used in phase measurement and detection devices, such as interferometers, optical receivers, and laser gyroscopes.

Abstract: There is disclosed a waveguide structure that propagates surface plasmon waves, comprising: a quantum well structure, disposed on a semiconductor substrate; wherein the quantum well structure has a quantum well layer, in turn having an intersecting region that intersects a hypothetical plane substantially orthogonal to an alignment direction of the quantum well structure with respect to the semiconductor substrate, and a real part of a dielectric constant of the quantum well structure is negative for THz waves of a predetermined wavelength.

Abstract: A polarization controller includes a plurality of liquid crystal cells positioned as cladding on a waveguide that propagates a beam of light so that the evanescent field extends into the liquid crystal cells, and a ½-wave birefringent retarder for rotating the eigenstates of polarization between the liquid crystal cells. For fast response, the evanescent field preferably extends only into the surface effect region of the liquid crystal cells, where directors in the liquid crystal respond faster to changes in voltages applied across the liquid crystal cells.

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: A system for transmitting the spatial profile of laser beams with particular applicability to coherently combine laser beams into one beam. The system includes a tapered waveguide with an inlet and outlet at ends of two waveguide elements each having a reflective surface facing into the waveguide. The reflective surfaces are non-parallel such that the inlet height is different than the outlet height, e.g., inlet height greater than outlet height. The system includes a beam input assembly controlling phases of laser beams input at the waveguide inlet, and the phases of the beams are locked to a substantially single phase. The waveguide length is selected to produce at the waveguide outlet a coherently combined laser beam from the input beams. The beam input assembly includes a laser beam source, a beam splitter generating lower power beams from source beams, and phase adjusters for controlling the phase of each input beam.

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: A multi-channel optical equalizer for intersymbol interference mitigation compensates for single- or multi-wavelength channels simultaneously and requires few adjustable parameters. The optical equalizer also compensates for overshoots and signal transition degradations in semiconductor optical amplifiers. The equalizer unit uses one control signal for magnitude and one to control signal phase. The equalizer includes a controllable coupling ratio coupler for splitting the light into two portions and a controllable interferometer having two arms, one arm having an additional delay which is equal to an integer multiple of 1/?f, where ?f is the channel spacing between adjacent wavelengths utilized in the optical system. The controllable interferometer has a controllable delay in a first or second arm for adjusting the relative phase of the light passing therethrough. A coupler combines the two signal portions from the first and second arms to form the equalized output signal.

Abstract: An interference waveguide device made of a material with a positive derivative of refractive index over temperature may be combined with a compensating waveguide device. The compensating waveguide device may be made of a material with opposite and larger derivative of refractive index. The outputs of the compensating device may be selectively coupled to inputs of the interference device to provide an athermal interference waveguide device.

Abstract: A strip to point optical communication system (200) for transmitting light between a first housing (102) and a second housing (104) of a device is provided. The strip to point optical communication system (200) includes a point optical communication element (202) that is capable of receiving the light. The point optical communication element (202) is coupled to either the first housing (102) or the second housing (104). The strip to point optical communication system (200) also includes a strip optical communication element (204) that is coupled to either the first housing (102) or the second housing (104) to which the point optical communication element (202) is not coupled. The length of the strip optical communication element (204) corresponds to the travel distance of the first housing (102) and the second housing (104). The strip optical communication element (204) is located to coincide with a travel path of the point optical communication element (202).

Abstract: A fiber optic switch uses induced periodic variations in a multi-mode optic fiber, to control power loss in the switch and power output.

Abstract: An optical phase modulator comprising a plurality of non-polarizing waveguides having a layered stack including a core between at least one layer of cladding material, wherein the core is constructed of electro-optic material(s), wherein the layers of cladding materials having lower indices of refraction than the core for guided mode, wherein the layer of cladding material having higher indices of refraction than the core for non-guided mode, a substrate dimensioned and configured to integrate a plurality of optical components, wherein the optical components include a plurality of non-polarizing waveguide(s), a waveguide having a non-polarizing non-modulating region and a non-polarizing modulating region, coupler/splitter(s), electrode(s), a waveguide configuration including a first non-polarizing waveguide, a second polarizing waveguide and a third waveguide, and at least two optical fiber pigtails where one is coupled to a second and third waveguide.

Abstract: A planar lightwave circuit coupler including first and second waveguides with curved coupling portions having radii of curvature selected such that the coupler has a splitting ratio that is substantially wavelength and polarization insensitive.

Abstract: The present invention relates to a monolithic optical component (400) comprising a light-absorbing layer and a waveguide structure (2). The invention is more particularly adapted to a monolithic component (400) comprising an evanescent coupling photodiode (6) integrated with the waveguide (2). The monolithic optical component (400) comprises a light-absorbing layer and a waveguide (2) evanescently coupled with the light-absorbing layer, the waveguide (2) having one end coupled to an input face (12) of the component to receive an input wave, the 10 component (400) being characterized in that the input face is convex.

Abstract: A method of measuring polarization mode dispersion (PMD) of an optical fiber, includes estimating PMD when an optical fiber is formed as an optical cable, from a beat length when the optical fiber is wound around a bobbin, and an average coupling length when the optical fiber is formed as the optical cable.

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: A system is provided for conversion of a first electromagnetic field into a desired second electromagnetic field, for example for coupling modes between waveguides or into microstructured waveguides. The system includes a complex spatial electromagnetic field converter that is positioned for reception of at least a part of the first electromagnetic field and that is adapted for conversion of the received field into the desired electromagnetic field, and wherein at least one of the first and second fields matches a mode of a microstructured waveguide. An advantage of the system is that the full effect of an incident light beam may be utilized for exciting a desired complicated mode of a specific waveguide. Another advantage is that the power of the incident beam may be coupled into one specific mode and not others, whereby a high mode suppression ratio may be achieved.

Abstract: A lossless optical coupler includes at least one input waveguide, at least two output waveguides and an intermediate optical splitter. The optical splitter of the present invention further comprises an active section adapted to provide contemporaneous splitting and amplification of an input optical signal. The arrangement of the present invention provides an inexpensive and compact integrateable coupling device.

Abstract: A nonlinear-optic waveguide device has a thin-wire optical waveguide including a core having a cross-sectional area of at most 1 ?m2 and a cladding, the core and the cladding having a refractive index difference of at least 1. A light pulse introduced into the core has a peak power of at least several hundreds W and a pulse duration of at most 10 ps. The thin-wire optical waveguide has a length of about 1 cm. The nonlinear optical device, a mode-locked semiconductor laser, and tunable optical filter are combined into a white pulse light source.

Abstract: A multi-mode optical fiber link is described that includes a single-mode optical fiber having an input that receives an optical signal for transmission through the multi-mode optical fiber link. A first spatial mode converter is coupled to the single-mode optical fiber. The first spatial mode converter conditions a modal profile of the optical signal for propagation through a multi-mode optical fiber. A multi-mode optical fiber is coupled to an output of the first spatial mode converter. A second spatial mode converter is coupled to an output of the multi-mode optical fiber. The second spatial mode converter reduces a number of optical modes in the optical signal. Both the first and the second spatial mode converters increase an effective modal bandwidth of the optical signal propagating through an output of the second spatial mode converter.

Abstract: An exemplary embodiment of the present invention described and shown in the specification and drawings is a system including an optical resonator and an optical element having a periodic structure for coupling of light into the optical resonator.

Abstract: A large mode area optical fiber includes a large diameter core (d1 up to 60 ?m), and a first cladding (diameter d2) wherein the difference between refractive index (n1) in the core and the first cladding (n2) is very small (?n<0.002), thus providing a very low numerical aperture core (NA1 between 0.02 and 0.06). The preferred ratio of d2/d1<2. The fiber further has a second cladding, preferably a layer of air holes, having a very low refractive index n3 as compared to the core and first cladding such that the first cladding has a relatively high numerical aperture (NA2>0.4) (n3 is preferably less than 1.3). The small change in refractive index between the core and inner cladding combined with a large change in refractive index between the first cladding and second cladding provides a significantly improved single mode holding waveguide.