Abstract: A dispersion compensating fiber 1 is placed in the form of a coil or bundle within a housing 2, and a filling material 3 having a viscosity of 0.01 Pa·s to 0.6 Pa·s at normal temperature before curing is filled in a space around the dispersion compensating fiber 1 within the housing 2 and then the filling material is cured. As a result, a change of transmission loss caused by a temperature variation due to heat cycles of the dispersion compensator can be reduced. A difference in transmission loss can be further reduced by employing a method of placing the dispersion compensating fiber in the housing in the form of a loosely wound bundle and then pouring the filling material, or a method of applying vibration to the housing, in which the dispersion compensating fiber is placed, when pouring the filling material.

Abstract: An optical fiber-based device exhibiting tunable birefringence utilizes a section of fiber including an optically nonlinear core region (i.e., doped with a material such as vanadium or erbium), where the fiber is configured to exhibit circular asymmetry and thus introduce birefringence into the fiber. The circular asymmetry may be accomplished by depositing the nonlinear core material in an asymmetric pattern or by launching the pump signal into an asymmetric mode of the fiber waveguide (i.e., an LP[1,m] mode). Polarization control can be generated by such a device through controlling the intensity of an input optical pump signal, since the pump signal intensity has been found to control the birefringence of a circularly asymmetric fiber waveguide.

Abstract: An electro-optical modulator includes an optical waveguide for carrying an optical carrier wave and a control waveguide for carrying a control wave. The optical waveguide includes a cladding layer and a core. The two waveguides are collinear and overlap in an interaction region so that the refractive index of the optical waveguide responds to electric fields generated by the control wave in the interaction region. The refractive index of the cladding layer at the control wave's wavelength is higher than the refractive index of the core at the optical carrier wave's wavelength.

Abstract: The invention provides an optical switch for operation by an incident light. The optical switch has a linear grating portion having an average linear refractive index and a nonlinear grating portion, meeting at an interface. The nonlinear grating portion includes a plurality of periodically alternating layers of nonlinear materials having different refractive indices. The linear grating portion and the nonlinear grating portion are positioned to form a continuous sequence of alternating high and low refractive indices at low intensities. The incident light is substantially reflected at low intensities. At high intensities, a continuous sequence of alternating high and low refractive indices is formed, interrupted by a discontinuity at the interface, and the nonlinear grating portion has a second average nonlinear refractive index which is substantially equivalent to the average linear refractive index. Light having a narrow band of frequencies is substantially transmitted at high intensities.

Abstract: A light-controlled light modulator can achieve high-speed, low-loss wavelength conversion. Continuous light with a wavelength &lgr;j is launched into an MMI coupler via a port, and is split into two parts by the MMI coupler, which are led to a loop-type interferometer. In the loop-type interferometer, the two parts travel separately around the loop as clockwise traveling light and counterclockwise traveling light, are combined by the MMI coupler again via a filter-equipped phase modulator, thereby being emitted to the port. In this state, signal light &lgr;i(s) with a wavelength &lgr;i is launched into the filter-equipped phase modulator via a port. Even when the wavelength &lgr;i of the signal light &lgr;i(s) is equal to the wavelength &lgr;j of the wavelength converted output light, the wavelength conversion can be achieved with preventing noise from being mixed into the output light emitted from a port.

Abstract: An optical switch/modulating device includes a pump waveguide that provides a pump light to the switch/modulating device. A waveguide element is positioned parallel to the pump waveguide and receives the pump light that causes the waveguide element to switch or modulate a signal light running through the pumped waveguide.

Abstract: An optically controlled switch includes first and second electrodes, a channel extending between the electrodes, and a light source positioned to illuminate the channel. The light source produces a wavelength capable of changing the material's conductivity. The channel includes a photosensitive organic material and is configured to operate as a light controlled switch.

Abstract: The invention relates to an optical signal transmission system with phase modulation and the implementation method. The system adds a phase modulator in the optical signal-emitting module. The optical pulses after intensity modulation and a high-speed data stream are input to the phase modulator synchronously, where the optical pulses are modulated in phase according to the high-speed data stream into high-speed optical signals with chattering. According to the invention, the phase modulator added in the optical signal-emitting module modulates optical signals in phase, which has been modulated in intensity. Appropriate chattering modulation can depress effectively the non-linear effect in the transmission of optical pulses through the interaction between chromatic dispersion and non-linear effects. Thus, the power input of individual channels is increased effectively, and the passive relay regeneration distance is extended.

Abstract: Optical apparatus and optical switching methods that provide optical high data rate switching at a wavelength or packet level using optical tone addressing. Optical signal routing is a result of optically induced total internal reflection at the intersection of an X-junction waveguide structure. The total internal reflection effect is controlled by a high intensity optical pump beam separate from the optical data signal. Total internal reflection may result from a free-carrier induced change in refractive index, which is a nonlinear effect found in common III-V semiconductors and selected polymers. Optical switching networks may be formed using cascaded pluralities of optical waveguide switches.

Abstract: An optical device provides optical routing functions, such as switching or redirecting of optical signals. The device utilizes one or more control light beams, which couple through a top surface of a planar substrate (via relatively small control windows) into one or more preselected regions of optical channels formed in the substrate. The presence of a control light beam at a control window increases the refractive index of the nonlinear optical medium of a portion of a channel. The portion of the channel includes a structure that functions as an on/off filter to reflect or transmit an optical signal propagating in the channel in a manner that is responsive to the intensity of the control light beam applied to the portion of the channel. In some embodiments, the optical channels interrupt a 2D PBG structure, which functions as a boundary for the optical channels.

Abstract: A Fabry-Perot optical switch includes a saturable absorber surrounded by a pair of mirrors. Coupled to the saturable absorber is an input waveguide, an output waveguide, and a control beam waveguide. In the absence of light input to the control beam waveguide, the saturable absorber prevents an input signal on the input waveguide from passing through and being output on the output waveguide, thus placing the switch in an “off” state. In the presence of light input to the control beam waveguide and incident on the saturable absorber, the saturable absorber allows the input signal to pass through and be output on the output waveguide, or be reflected and output on the output waveguide, thus placing the switch in an “on” state.

Abstract: The invention concerns the area of nonlinear fiber and integrated optics, to be exact the area of completely optical switches, modulators and optical transistors, in which solitons are used. The technical problem of the invention is the diminution of pump energy fed into optical waveguide, and also increase of sharpness and depth of switching, and gain of optical transistor, and switching speed as well. One variant of the method consists in that into input of tunnel-coupled waveguides having cubic nonlinearity and the second-order dispersion, they feed radiation as fundamental solitons or pulses close to them in amplitude and in shape with various maximum intensity, which is in limits from 0.6IMup to 1.4IM, where IM is the critical intensity. In other variants of the method additionally into the input of the same or other waveguide they feed radiation, which intensity is much less comparable with the soliton's intensity. In particular, this radiation can be as solitons.

Abstract: An optical device provides optical routing functions, such as switching or redirecting of optical signals. The device utilizes one or more control light beams, which couple through a top surface of a planar substrate (via relatively small control windows) into one or more preselected regions of optical channels formed in the substrate. The presence of a control light beam at a control window increases the refractive index of the nonlinear optical medium of a portion of a channel. The portion of the channel includes a structure that functions as an on/off filter to reflect or transmit an optical signal propagating in the channel in a manner that is responsive to the intensity of the control light beam applied to the portion of the channel. In some embodiments, the optical channels interrupt a 2D PBG structure, which functions as a boundary for the optical channels.

Abstract: The present invention provides a method for fast switching of optical properties in photonic crystals using pulsed/modulated free-carrier injection. The results disclosed herein indicate that several types of photonic crystal devices can be designed in which free carriers are used to vary dispersion curves, stop gaps in materials with photonic bandgaps to vary the bandgaps, reflection, transmission, absorption, gain, or phase. The use of pulsed free carrier injection to control the properties of photonic crystals on fast timescales forms the basis for all-optical switching using photonic crystals. Ultrafast switching of the band edge of a two-dimensional silicon photonic crystal is demonstrated near a wavelength of 1.9 &mgr;m. Changes in the refractive index are optically induced by injecting free carriers with 800 nm, 300 fs pulses. Band-edge shifts have been induced in silicon photonic crystals of up to 29 nm that occurs on the time-scale of the pump pulse.

Abstract: A fully light-controllable integrated optical switch applicable in a slab geometry configuration includes a waveguide and an ad-medium in contact with the waveguide. The the ad-medium comprises a photochromic protein as a material of non-linear optical property, wherein switching of a light propagating in the waveguide is effected by a change of an optical property of the ad-medium caused by a light-induced transition of the photochromic protein from one defined molecular state to another.

Abstract: A fast, environmentally-stable fiber switch uses a Sagnac interferometer having an active fiber portion located asymmetrically in the loop of the interferometer. A pump pulse is applied to the interferometric loop and acts upon the active fiber portion to cause a change in its refractive index either by a thermal effect or by a non-thermal nonlinear effect. Because the active fiber portion is located asymmetrically in the loop, the change in refractive index of the active fiber portion is seen by the clockwise propagating light signal and the counterclockwise propagating light signal at different times, thus causing a temporary difference in the phase changes experienced by the two counterpropagating light signals.

Abstract: The invention has improved parameters when compared iwth prior art devices; pump power was decreased by four orders of magnitude and amplification of signal was increased by two orders of magnitude. The main features of the invention are the following. A nonlinear optical waveguide is made on the basis of a layered MQW-type structure, where unidirectional distributively coupled waves (Ip, Is), e.g. coupled waves having orthogonal polarizations, interact. The wavelength of optical radiation is chosen close to the wavelength of resonance in the structure. Input/output elements, taking into account the asymmetry of the cross section of the nonlinear optical waveguide, are mounted at the input and output of the nonlinear waveguide making up a compact nonlinear-optic module. A small electric current is injected across said nonlinear optical waveguide through electrodes, so as to increase the gain and decrease the pump optical power to a high degree.

Abstract: An optical device for serializing data signals in a plurality of parallel channels is disclosed, including: (a) a plurality of waveguides adapted to conduct light signals of a predetermined wavelength; and (b) a nonlinear optical element having a refractive index and defining an optical path thereon adapted and configured to conduct a control light pulse along the optical path, wherein a portion of each of the plurality of waveguides is adjacent to or in contact with the nonlinear optical element at a different portion along the optical path; wherein the refractive index along the optical path is substantially altered where the control pulse is located such that the relative phase of the light signals of the predetermined wavelength is altered only where the signal is substantially coincident with the control pulse.

Abstract: An optical switch includes a saturable absorber. Coupled to the saturable absorber is an input waveguide, an output waveguide, and a control beam waveguide. In the absence of light input to the control beam waveguide, the saturable absorber prevents an input signal on the input waveguide from passing through and being output on the output waveguide, thus placing the switch in an “off” state. In the presence of light input to the control beam waveguide and incident of the saturable absorber, the saturable absorber allows the input signal to pass through and be output on the output waveguide, thus placing the switch in an “on” state.

Abstract: A system for alternately directing optical energy through multiple optical modulation channels includes an optical switch having first and second optical output ports for alternately directing an optical signal at full input power out of first and second optical output ports; a first optical modulation channel for modulating the output signal received from the first optical output port; and a second optical modulation channel for modulating the output signal received from the second output port. The optical switch includes a Pockels cell and a birefringent mirror. The Pockels cell transforms a first polarization state of the optical signal into a second polarization state in response to receiving an input signal. The birefringent mirror allows the optical signal to propagate along a first axis when the optical signal has a first polarization state, and directs the optical signal along a second axis when the optical signal has a second polarization state.

Abstract: A traveling wave optical modulator includes an optical waveguide substrate made of an electro-optic and ferrodielectric single crystal in the form of an X- or Y-orientation plate_and comprising a thicker portion having a larger thickness and a thinner portion having a smaller thickness; first and second branched optical waveguide portions formed at least on the thinner portion of the optical waveguide substrate; a set of electrodes provided on at least the thinner portion of the substrate and adapted for applying voltage to the first and second optical waveguide portions to modulate a light propagating the optical waveguide portions; and a buffer layer provided to cover a part of the optical waveguide portions at the thinner portion of the substrate, the electrodes crossing on the buffer layer.

Abstract: A security device for a slide fastener, including a housing adapted to be fitted to an object to which the slide fastener is attached, the housing substantially surrounding the slider of the slide fastener in its fully closed position, a closure member adapted to cooperate with the housing which, in use, covers the slider to prevent access thereto and a frangible locking element adapted to link the housing to the closure member, the locking element being resiliently yieldable and slidably insertable into the closure member but not retractable therefrom without fracturing the frangible locking element. The closure member is attached at one end to a puller and the puller is attached to the slider. In a preferred embodiment the closure member can pivot about the housing and block withdrawal of the slider from the housing in its closed position.

Abstract: An optical interconnect for use with a probe beam and optical signals is disclosed. The interconnect comprises an optical waveguide for propagating the probe beam, an optical transcription material that changes a characteristic of the probe beam at locations where the optical signals interact with the probe beam. A signal processor develops an output signal from the changed characteristic representative of the information contained in the optical signals. The optical signals may be amplitude or phase modulated or polarized. The interconnect can be configured to add and subtract the optical signals.

Abstract: The present invention provides a method and apparatus for an optical processor. Polymerizable compounds in a specific composition containing photo-reactive materials, optically polar materials, and optical materials which can be cured with actinic radiation to form polymeric compositions, are provided. The resultant polymeric compositions are capable of forming complex optical interconnecting network structures. The optical networks may also be placed on a rotatable microdisk, thereby increasing the number of functions able to be carried out with the present invention. Also, the rotatable microdisks may be stacked upon each other, increasing the number of functions of the invention still further.

Abstract: A class of molecules suitable for linear and nonlinear optical applications which include charged aromatic groups which function as electronic donors and acceptors connected through polyhedral and &pgr;-organic and inorganic groups. The polyhedral and &pgr;-organic and inorganic groups function as structural and electronic bridges for the charged donors and acceptors.

Abstract: An optically controlled switch includes first and second electrodes, a channel extending between the electrodes, and a light source positioned to illuminate the channel. The light source produces a wavelength capable of changing the material's conductivity. The channel includes a photosensitive organic material and is configured to operate as a light controlled switch.

Abstract: A waveguide structure comprising a medium disposed of a sensing layer (21), a second layer of material (22) having a refractive index greater than that of the medium, and a substrate (24). The structure defines a waveguide capable of supporting an optical mode confined in a sensing layer. The medium is adapted for performing chemical or biological reactions within the medium which will result in a change of an optical property of the sensing layer of the waveguide. The thickness and refractive indexes of the layers are chosen such that an optical mode confined in the sensing layer will suffer substantially anti-resonant reflection as a consequence of the interface between the sensing layer and the second layer and the interface between the second layer and the substrate. Alternatively, the waveguide may comprise a low index sensing medium held between a superstrate and a substrate each of which has a refractive index higher than that of the medium.

Abstract: An optical device includes a plurality of first optical waveguides (or optical fibers) arranged in the horizontal direction; a plurality of second optical waveguides (or optical fibers) arranged on the same plane as the plane on which the first optical waveguides (or optical fibers) are arranged, the second optical waveguides (or optical fibers) being perpendicular or nearly perpendicular to the first optical waveguides (or optical fibers); and elements to be excited by light rays waveguided in the first and second optical waveguides(or optical fibers), the elements being arranged at crossing portions at which the first and second optical waveguides (or optical fibers) cross each other.

Abstract: In the band edge region, transmission and reflection of an optical wave can be made very sensitive to the change in radiation wavelength, a change in the modulator material refractive index, and/or a change in the material absorption. Controlling these parameters with the increased level of sensitivity is provided by modulation using the band edge region. A preferred embodiment method of the invention uses a periodic optical structure (i.e., a grating) on top of an optical waveguide structure. The combination of the periodic structure and the optical waveguide is designed so that the reflection and/or transmission of the guided wave have broad pass bands with narrow transition bands. The optical structure is exposed to an incident laser radiation with wavelength in one of the transition bands. Modulation of the incident laser radiation is controlled by the change in refractive index or absorption in the optical guided wave structure produced by the modulation voltage.

Abstract: A fast, environmentally-stable fiber switch uses a Sagnac interferometer having an active fiber portion located asymmetrically in the loop of the interferometer. A pump pulse is applied to the interferometric loop and acts upon the active fiber portion to cause a change in its refractive index either by a thermal effect or by a non-thermal nonlinear effect. Because the active fiber portion is located asymmetrically in the loop, the change in refractive index of the active fiber portion is seen by the clockwise propagating light signal and the counterclockwise propagating light signal at different times, thus causing a temporary difference in the phase changes experienced by the two counterpropagating light signals.

Abstract: Non-linear reflectivity and non-linear transmissivity of a first photonic signal incident on a photonic band gap (PBG) structure are controlled by applying a second photonic signal to the PBG structure while the first photonic signal is incident on the PBG structure. The first and second photonic signals have respective frequencies near a low frequency, first order band gap edge and a high frequency, second order band gap edge resonance peak of the PBG structure. The first photonic signal undergoes enhanced non-linear gain near the band gap edges when a predetermined phase difference is imposed between the first and second photonic signals, resulting in dramatic reflectivity and transmissivity changes for a band gap structure of only a few microns in length.

Abstract: A Fabry-Perot optical switch includes a saturable absorber surrounded by a pair of mirrors. Coupled to the saturable absorber is an input waveguide, an output waveguide, and a control beam waveguide. In the absence of light input to the control beam waveguide, the saturable absorber prevents an input signal on the input waveguide from passing through and being output on the output waveguide, thus placing the switch in an “off” state. In the presence of light input to the control beam waveguide and incident on the saturable absorber, the saturable absorber allows the input signal to pass through and be output on the output waveguide, or be reflected and output on the output waveguide, thus placing the switch in an “on” state.

Abstract: A photonic band gap structure device and method for delaying photonic signals of a predetermined frequency and a predetermined bandwidth by a predetermined delay is provided. A Fabry-Perot delay line device has several regions of periodically alternating refractive material layers which exhibit a series of photonic band gaps and a periodicity defect region, interposed between the regions of periodically alternating refractive material layers. The Fabry-Perot delay line device imparts a predetermined delay to photonic signals that pass therethrough. The introduction of the periodicity defect region into this photonic band gap structure creates a sharp transmission resonance within the corresponding photonic band gap of the structure and causes at least an order of magnitude improvement in photonic signal delay for a band-edge delay line device of similar size. Variable photonic delays to multiple photonic signals are also generated by this Fabry-Perot delay line device.

Abstract: A fast, environmentally-stable fiber switch uses a Sagnac interferometer having an active fiber portion located asymmetrically in the loop of the interferometer. A pump pulse is applied to the interferometric loop and acts upon the active fiber portion to cause a change in its refractive index either by a thermal effect or by a non-thermal nonlinear effect. Because the active fiber portion is located asymmetrically in the loop, the change in refractive index of the active fiber portion is seen by the clockwise propagating light signal and the counterclockwise propagating light signal at different times, thus causing a temporary difference in the phase changes experienced by the two counterpropagating light signals.

Abstract: An optical switch is formed by introducing light lengthwise to a microcantilever waveguide directed toward a second waveguide. The microcantilever is caused to bend by light emitted from a laser diode orthogonal to the microcantilever and at an energy above the band gap, which induces stress as a result of the generation of free carriers. The bending of the waveguide directs the carrier frequency light to a second receptor waveguide or to a non-responsive surface. The switch may be combined in an array to perform multiple switching functions rapidly and at low energy losses.

Abstract: A light tunnel apparatus (200 or 300) having an output end (56 or 98), for uniformizing light (L) that travels through a light tunnel (30 or 80). The apparatus comprises a light tunnel having first and second sides (36, 40 or 86, 90), and one or more AO modulators (210 or 310) respectively arranged on at least one of the first and second sides. The AO modulators are arranged such that activating the one or more of them causes at least one of the first and second sides to be displaced. This displacement changes the path of light traveling through the light tunnel by an amount sufficient to reduce illumination non-uniformities at the output end. The light tunnel may be a hollow light tunnel (30) with reflective inner surfaces, or a solid light tunnel (80) with a refractive index. A method of uniformizing illumination using a light tunnel is also disclosed.

Abstract: The invention provides organic optical waveguide devices which employ perfluoropolymeric materials having low optical loss and low birefringence. An optical element has a substrate; a patterned, light transmissive perfluoropolymer core composition; and a light reflecting cladding composition on the pattern of the core. Writing of high-efficiency waveguide gratings is also disclosed.

Abstract: The present invention is to provide a multi-channel variable optical attenuator with a small size and a simple control circuitry, which requires a short time for adjusting the attenuation level of signal lights. The optical attenuator comprises an optical attenuating portion 10, a control circuitry 20 and a master control circuitry 21. The optical attenuating portion includes a plurality of optical waveguides 121-12N and a plurality of attenuation adjusting portions 131-13N, both of which is formed in a substrate 11. A signal light of a specific wavelength &lgr;i, which is derived from the wavelength multiplexed light, transmits in a respective waveguide 12i and is attenuated by a specific amount at the attenuation adjusting portion 13i. The control circuitry 20outputs a plurality of control signals 141-14N to attenuation adjusting portions 131-13N so that the attenuation in each optical waveguides 121-12N is varied by the specific amount to the master control 22 sent from the master control circuitry 21.

Abstract: The present invention relates to an improved process for photorefractive index grating formation utilizing polymeric photorefractive materials. The process involves the steps of: (i) exposing a polymeric optical article to electromagnetic radiation having an intensity of at least 0.05 W/cm2 for a short period of time to achieve an absorbed energy/unit volume of at least 1×103 J/cm3 to activate the article, and (ii) exposing the polymeric optical article to an electric field and electromagnetic radiation to form an index grating.

Abstract: An optical waveguide element includes a substrate showing electrooptical effects and having a pair of major planes opposed with each other, an optical waveguide formed on one major plane of the substrate, and an electrode for applying a modulation signal to an optical wave transmitted through the optical waveguide. In the optical waveguide element mentioned above, there are a thin thickness portion having a relatively thin thickness formed to a portion of said substrate at least positioned correspondingly to said electrode; and a buffer layer formed between said substrate and said electrode, wherein an impedance conformity with the modulation signal applied to said electrode is performed by controlling a thickness of said thin thickness portion.

Abstract: A method for fabricating low-loss optically active device having an optical waveguide constructed of an optical waveguide core region (non-linear core region) necessitating the non-linear effect when waveguiding an optical signal, and an optical waveguide core region (linear core region) not necessitating the non-linear effect, the method includes method for fabricating an optically active device having an optical waveguide constructed of an optical waveguide core region (non-linear core region) necessitating the non-linear effect when waveguiding an optical signal, and an optical waveguide core region (linear core region) not necessitating the non-linear effect, the method includes the steps of: forming a lower clad layer having a refractive index lower than the material of the waveguide core regions and optical transparency on a substrate, forming a linear optical polymer layer on the lower clad layer by coating linear optical polymer having a refractive index lower than the material of the lower clad layer

Abstract: An optical switch having a straight waveguide core with a lateral waveguide core extending therefrom. A region of polymer material is disposed in the straight waveguide core to deflect optical waves from the first waveguide core into the lateral waveguide core depending on the relative indexes of refraction between the first waveguide core and the polymer material. The temperature of the polymer material is adjusted, thereby adjusting the index of refraction of the polymer material so as to cause the deflection in a switched state, and to allow light radiation to pass through the polymer material in an un-switched state.

Abstract: An optical processor comprising, a semiconductor saturable absorber; a current source for injecting a current to the semiconductor saturable absorber; a signal light introducer for introducing a signal light to the saturable absorber; a control light introducer for introducing a control light having a wavelength not longer than the wavelength of the signal light into the semiconductor saturable absorber; an assist light introducer for introducing an assist light having a wavelength longer than the wavelength of the signal light into the semiconductor saturable absorber; and a signal light extractor for extracting the signal light after treatment by the semiconductor saturable absorber.

Abstract: A method of forming waveguides, refractive index distributions and optical couplings automatically by light incidence, and devices obtained thereby. A non-linear optical material which has excellent properties of a large degree of freedom for an optical circuit substrate composition, etc. is used for optical circuit devices and optical circuit substrates. A photoelectric device containing an organic conjugated polymer film is deposited on a substrate by vapor deposition polymerization as at least one function layer. An optical network is provided with optical wiring for exchanging signals between processing elements selected from electronic elements, electronic apparatuses, electrooptical elements and electrooptical apparatuses.

Abstract: A metallic film has apertures located therein in an array arranged in a pattern so that when light is incident on the apertures, surface plasmons on the metallic film are perturbed resulting in an enhanced transmission of the light emitted from individual apertures in the array. The aperture array is used: to filter light of predetermined wavelength traversing the apertures, to collect light over a distance after traversing the apertures, to improve operation of near-field scanning optical microscopes, and to enhance light transmission through masks useable in photolithography.

Abstract: A system for summing RF modulated optical signals. In order to compensate for performance degradation at the summing junction, the system utilizes four-wave mixing elements to provide the phase conjugates of each of the modulated RF signals. The phase conjugates of the RF modulated optical signals are summed at the summing junction. The use of the phase conjugates of the RF modulated optical signals compensates for optical phase errors known to degrade performance when summing RF modulated optical signals.

Abstract: In an electroabsorption optical intensity modulator, a semiconductor buffer, a first semiconductor cladding layer, a semiconductor optical absorption layer, a second semiconductor cladding layer and a semiconductor cap layer are formed on a semiconductor substrate. Also, a first electrode is formed on the second semiconductor cap layer, and a second electrode is formed on a second surface of the semiconductor substrate. The semiconductor optical absorption layer includes a first semiconductor optical absorption layer element having a first absorption edge wavelength and a second semiconductor optical absorption layer element having a second absorption edge wavelength different from the first absorption edge wavelength.

Abstract: An electro-optic modulator is disclosed in the form of a compound waveguide device having a channel waveguide in optical proximity to an elongate waveguide propagating an optical signal therein. The channel waveguide includes a coupling surface through which optical energy is evanescently coupled to or from the optical signal propagating in the elongate waveguide. The channel waveguide is shaped to confine distribution of the optical energy therein along axes transverse to the axis of propagation of the optical energy. Transverse diffraction of the optical energy within the channel waveguide is thereby limited. The channel waveguide is formed from an electro-optically active material, and modulation of the optical signal propagating in the elongate waveguide is effected using the evanescent coupling effect between the two waveguides. In one embodiment, the elongate waveguide is a side-polished fiber-optic waveguide.

Abstract: A thermally activated silica optical circuit switch that uses light from a light source, such as a laser, to heat various regions of the switch to produce a switching function. In one embodiment, the switch includes silica glass formed on a substrate, such as a silicon substrate, and at least one input waveguide and one output waveguide formed within the silica glass. A light source is then used to generate light that illuminates a path in the silica glass that couples a particular input waveguide to a particular output waveguide. The light from the light source has a wavelength that enables it to be substantially absorbed by the silica glass and substantially transmitted through the substrate. The illumination by the light increases the temperature and correspondingly the index of refraction of the silica glass in the path. A light signal is then able to travel through the coupled waveguides via the increased index of refraction of the silica glass within the path.

Abstract: The frequency of a first optical clock signal that is approximately sinusoidal and has a frequency f.sub.0 is doubled by all-optical means. A non-linear optical loop mirror (NOLM) is used as an optical modulator, being controlled by the first clock signal at f.sub.0 to modulate a continuous second signal introduced at the signal input of the NOLM. The modulated signal at the frequency 2f.sub.0 is recovered at the output of the NOLM. Two wavelengths are advantageously used for the first and second signals, these two wavelengths having substantially the same group velocity in the NOLM. In an important implementation the peak-to-peak power of the first control signal is much less than the power needed to maximize the switching effect of the NOLM on the second signal. The invention also concerns a soliton regenerator using this optical doubling method. Applications include fiber optic telecommunications, in particular using solitons.