Abstract: An optical circuit system which takes out at least a portion of the light of a light power source corresponding to at least one type of output voltage of an IC, board, multichip module, electronic element, or opto-electronic element and produces an optical signal, wherein the light power source is an optical waveguide into which light has been introduced, a waveguide laser, or a waveguide optical amplifier, light reflecting portions are provided at its ends and/or middle, a signal transmission waveguide is formed in contact with the side surface and/or top or bottom surface of the optical waveguide or in proximity to the same at a certain distance, and the optical signal corresponding to at least one type of output voltage of the IC, board, multichip module, electronic element, or opto-electronic element is made to propagate to the signal transmission waveguide, which optical circuit system is rich in flexibility and enables complicated optical interconnections to be handled, and components of the same.

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: A tunable waveguide filter, formed from two waveguides, has an improved selectivity. The filter is tuned by passing a current through the filter. One of the waveguides is a semi-active waveguide. The increased absorption of charge carriers that occurs when current is injected into the semi-active waveguide is compensated by gain enhancement in the waveguide, because the material used for the semi-active waveguide is selected to provide an appropriate amount of gain. Therefore, the gain compensates for the losses that arise from free carrier absorption when the tuning current is applied to the filter.

Abstract: A wavelength characteristic control device capable of variably controlling a wavelength characteristic in a satisfactory manner. A polarized light wavelength characteristic changing element has a wavelength characteristic such that the transmittances or reflectances of P- and S-polarized rays vary differently with respect to wavelength. Polarization variable control means subjects the plane of polarization of the polarized light incident on the polarized light wavelength characteristic changing element to rotatory control to change the ratio of the P-polarized ray to the S-polarized ray, thereby variably controlling the wavelength characteristic.

Abstract: An electro-optic modulator having a continuously adjustable chirp is provided. Optical signals input into the electro-optic modulator are divided into portions which are phase modulated in opposite senses, one portion imparted with a positive chirp and the other with a negative chirp. Variable couplers are used to adjust (by way of adjusting their coupling ratios) the amount of power allocated between the optical signals contributing to the positive chirp and the power of signals contributing to the negative chirp so that when the optical signals are combined an optical signal with an adjustable chirp is produced.

Abstract: Optical devices and methods for attenuating, shuttering, or switching optical signals as found in telecommunications. A platform carrying a portion of a waveguide and residing in a plane of a substrate is tipped, tilted, twisted, or otherwise moved out of the plane of the substrate to divert the path of an optical signal or to change coupling between adjacent waveguides. The platform can be formed by etching a substrate while leaving one or more connection points between the platform and the substrate to hold the platform to the substrate.

Abstract: A Mach-Zehnder interferometer is employed to implement phase modulation of an optical signal. The interferometer is biased at its maximum extinction point. The modulated optical signal may have a peak magnitude between approximately 30% and 80% of a maximum output power of the interferometer.

Abstract: Electrically switchable optical elements, such as application specific integrated elements including filters, lenses and switches, are combined with wavelength locked feedback loops. Electrically Switchable Bragg Grating (ESBG) technology is combined with a wavelength locked feedback loop to provide variable focal length optical systems which automatically adjust the focal length of incident light.

Abstract: An optical modulator has optical channels formed in a waveguide substrate in which two of the waveguide channel branches have reverse polarity relative to each other. In addition, the optical modulator has at least one of the following: 1) an electronic signal electrode and an electronic ground electrode are placed in proximity with opposite faces of the waveguide substrate, 2) a portion of said waveguide substrate is removed to afford a reduced electronic signal refractive index, and 3) the waveguide substrate has a fixing substrate attached to it with the refractive index of the fixing substrate lower than said refractive index of the waveguide substrate.

Abstract: An optical delay generator comprises a first waveguide made from electro-optically active material resonantly coupled to a second non-electro-optically active waveguide. The first waveguide contains a chirped distributed Bragg reflector structure which reflects optical signals at a specific wavelength at a specific reflection point within the structure. An electric field applied to the first waveguide changes the refractive index of the electro-optically active material and thus shifts the reflection point. Optical signals reflecting from the reflection point are resonantly coupled into the second waveguide, and are thus not affected by the electric field applied to the first waveguide. The controllable optical delay applied to the optical signals results from control over the reflection point and the round-trip travel time for an optical signal forward propagating in the first waveguide, being reflected at the reflection point, and backward propagating in the second waveguide.

Abstract: An optical semiconductor device includes an optical modulator and an optical detector formed integrally on a common substrate to form an optical integrated circuit, wherein an optical beam spot conversion part is provided also integrally on the common substrate so as to connect an output end of the optical modulator and an input end of the optical detector.

Abstract: The invention provides an optical modulator which suppresses the loss of a microwave which advances through an electrode and of light which propagates in a waveguide and makes the losses in individual arm waveguides substantially equal to each other to suppress the deterioration of the extinction coefficient to improve the transmission quality. The optical modulator includes a substrate having an electro-optical effect and having a ridge, first and second grooves and first and second banks formed thereon, a Mach-Zehnder optical waveguide, an electrode, and first and second recesses formed at symmetrical positions with respect to the ridge on the first and second banks, respectively. The optical modulator is applied, for example, to a transmission side apparatus for a long distance optical transmission system.

Abstract: An add/drop filter for optical wave energy incorporates a Bragg grating in a very narrow waist region defined by merged lengths of elongated optical fibers. Light is propagated into the waist region via adiabatically tapered fibers and is transformed from two longitudinally adjacent fibers into two orthogonal modes within the air-glass waveguide of the waist and reflected off the grating from one fiber into the other. The geometry of the waist region is such that the reflected drop wavelength is polarization independent, without lossy peaks in the wavelength band of interest. Additionally, back reflection are shifted out of the wavelength band of interest. High strength gratings are written by photosensitizing the waist region fibers by constantly in-diffusing pressurized hydrogen or deuterium. For narrow spectral bandwidth gratings, dimensional variations must be minimized or compensated, and the grating is apodized by both a.c. and d.c. variations in writing beams at a net constant power.

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 planar waveguide-type optical amplifier switch is disclosed. The switch is developed with the purpose of solving the problems that the conventional waveguide-type optical switch, which has been being used in the optical communication technique, has an optical loss and thereby requires an external optical amplifier which makes the whole devices not suitable for forming an integrated compact device. The disclosed switch performs switching function from the refractive index change in the optical waveguides induced by electrical or optical controls as well as amplifying function of the optical signal, when it passes through the waveguides, from use of optical waveguides formed of a fluorescence emitting material with an optical pumping and a wavelength division multiplexing (WDM) optical waveguide-type coupler.

Abstract: An optical waveguide modulator 40 has a substrate 1 made of a material with an electrooptic effect, an optical waveguide 2 to guide a lightwave 2, a travelling wave-type signal electrode 3 and the ground electrodes 4 to control the lightwave. Moreover, it has a buffer layer 6, at least a part thereof being embedded in the superficial layer of the substrate 1, having a larger width “W” than a width “&ohgr;” of the travelling wave-type signal electrode 3 only under the signal electrode 3 and its nearby part.

Abstract: An apparatus and associated method for altering the propagation constant of a region of deflecting propagation constant in an optical waveguide. The method comprising positioning an electrode of an electrode shape proximate the waveguide. A region of deflecting propagation constant is projected into the waveguide and corresponds, in shape, to the electrode shape by applying a voltage to the shaped electrode. The propagation constant of the region of deflecting propagation constant is controlled by varying the voltage that adjusts a deflection angle applied to an input optical signal flowing through the waveguide.

Abstract: An apparatus and associated method for altering the propagation constant of a region of filtering propagation constant in an optical waveguide. The method comprising positioning an electrode of an electrode shape proximate the waveguide. An altered region of filtering propagation constant is projected into the waveguide that corresponds, in shape, to the electrode shape by applying a voltage to the shaped electrode. The propagation constant of the region of filtering propagation constant is controlled by varying the voltage. Such filter embodiments as an Infinite Impulse Response filter and a Finite Impulse Response filter may be provided.

Abstract: An optical delay generator comprises a first waveguide made from electro-optically active material resonantly coupled to a second non-electro-optically active waveguide. The first waveguide contains a chirped distributed Bragg reflector structure which reflects optical signals at a specific wavelength at a specific reflection point within the structure. An electric field applied to the first waveguide changes the refractive index of the electro-optically active material and thus shifts the reflection point. Optical signals reflecting from the reflection point are resonantly coupled into the second waveguide, and are thus not affected by the electric field applied to the first waveguide. The controllable optical delay applied to the optical signals results from control over the reflection point and the round-trip travel time for an optical signal forward propagating in the first waveguide, being reflected at the reflection point, and backward propagating in the second waveguide.

Abstract: A directional optical coupler is shown and described, which includes an optical cell that is made of a first transparent conductor, a second transparent conductor and an electro-optical member interposed between the two transparent conductors, the electro-optical member having an index of refraction which can be varied only along one crystal axis by application of an electric field.

Abstract: A wavelength tunable optolelectronic device. Two channel waveguides are provided in an optoelectronic structure made of a ferroelectric material. The waveguides are adjacent along at least a coupling region. A periodically poled structure is provided in the coupling region, and at least one of the waveguides is untouched by this structure. An electric field is applied in the coupling region, through both waveguides, to enable coupling a light of a given wavelength between the two waveguides. The amplitude of the electric field may be selected to tune the coupling wavelength. A third waveguide or more having a coupling region in common with the second waveguide may also be added to allow the bandwidth of the resulting beam to also be tuned.

Abstract: An integrated photonic apparatus that includes a glass substrate having a major surface, wherein the glass substrate includes a plurality of regions, each region having a different index of refraction, including a first region having a first index of refraction and a second region having a second index of refraction lower than the first index of refraction, and a first waveguide formed along the major surface of the substrate, wherein the first waveguide has a higher index of refraction than an intrinsic index of refraction of adjacent portions of the substrate, and wherein the first waveguide passes through the first region and through the second region of the glass substrate.

Abstract: An improved polarization control method and apparatus is provided. The described invention uses super-polished squeezing surfaces to apply pressure against a polyimide coated fiber thereby minimizing micro-bending effects that cause losses in the fiber. Special control circuitry has also been designed to maintain a driving source of piezo-electrics that control the squeezing surfaces at a resonant frequency, thereby minimizing the voltages needed to drive the piezo-electrics.

Abstract: The travel range is extended for electrostatically actuated micro mirrors used as attenuators, modulators and switches in optical networks by the use of dielectrically coated, preferably with Silicon dioxide, inner surfaces. Oxide charge and oxide capacitance combine to expand the travel range of the mirrors before snap down, at the expense of increased applied bias voltage. This method of travel range extension is preferred over other range extension methods due to its simplicity, reproducibility, and ease of manufacture, as well as benefits of decreased stiction and inhibited electrode shorting. A method for the manufacture of the devices is also disclosed.

Abstract: A thermal optical switching cell for controlling the transmission of light through optical channels that includes a switching conduit containing a working fluid that is index of refraction matched to the optical channels and an amount of light diverting material that is substantially immiscible in the working fluid and is not index of refraction matched to the optical channels. Micro heaters generate pressure pulses in the working fluid for moving the light diverting material between switch states.

Abstract: A circular polarization modulator operable to output light alternating in time between left-hand and right-hand circular is provided. The circular polarization modulator preferably comprises three elements: a TE-TM mode-excitation balancer, a TE-TM phase-difference modulator and a TE-TM mode-shape matcher. The TE-TM mode-excitation balancer, which may include a DC voltage source and is preferably based upon a tilt-poled polymer, preferably produces light having as near equally excited TE and TM modes as a forty-five degree (45°) linear input polarization may provide. The TE-TM phase-difference modulator preferably includes an AC voltage source and provides wave retardation capable of producing a phase difference between the TE and TM waves.

Abstract: An optical device assures high speed drive, excellent temperature stability, low drive voltage and small crosstalk and insertion loss. The optical device includes a single crystal substrate which is used as a conductive or semiconductive lower electrode, an epitaxial buffer layer consisting of an oxide provided on the single crystal substrate, an epitaxial optical waveguide layer with an oxide ferroelectric material having an electro-optic effect which is provided on the buffer layer and which has a channel optical waveguide of which an optical path is switched when a voltage is applied to the branching portion between an optical path for incident light and an optical path for outgoing light, and a couple of upper electrodes for applying a voltage to the branching portion of the channel optical waveguide.

Abstract: This invention discloses a selectably directable optical beam deflecting device including at least at least one substrate having formed thereon a multiplicity of waveguides, each waveguide receiving light and emitting light, the totality of light emitted by said multiplicity of waveguides producing at least one selectably directable output beam, and at least one multiplexer applying electrical inputs to the at least one substrate for individually controlling the light emitted by each of the multiplicity of waveguides, thereby governing the orientation of the selectably directable output beam.

Abstract: This invention discloses a selectably directable optical beam deflecting device including at least at least one substrate having formed thereon a multiplicity of waveguides, each waveguide receiving light and emitting light, the totality of light emitted by said multiplicity of waveguides producing at least one selectably directable output beam and at least one multiplexer applying electrical inputs to the at least one substrate for individually controlling the light emitted by each of the multiplicity of waveguides, thereby governing the orientation of the selectably directable output beam.

Abstract: In accordance with the invention, a wavelength stable optical source comprises at least one adjustable wavelength optical source, a multipath Mach-Zehnder interferometer (MMZI) for receiving a signal from the adjustable source and providing a primary output and one or more secondary outputs, and a feedback arrangement responsive to the outputs for adjusting the wavelength source. Photodetectors coupled to the primary output and one or more of the secondary outputs provide feedback information for maintaining wavelength stability.

Abstract: An optical waveguide phase adjuster with enhanced sensitivity for instance for use in a Mach Zehnder has a monolithic integrated optics waveguide across which one or more thin, e.g. 10 &mgr;m, slots are made. The slots are filled with material whose refractive index varies strongly with temperature or applied field. The insertion loss of such a slot is small for thicknesses of less than about 25 &mgr;m, but begins to rise ever more rapidly thereafter.

Abstract: A wavelength characteristic control device capable of variably controlling a wavelength characteristic in a satisfactory manner. A polarized light wavelength characteristic changing element has a wavelength characteristic such that the transmittances or reflectances of P- and S-polarized rays vary differently with respect to wavelength. Polarization variable control means subjects the plane of polarization of the polarized light incident on the polarized light wavelength characteristic changing element to rotatory control to change the ratio of the P-polarized ray to the S-polarized ray, thereby variably controlling the wavelength characteristic.

Abstract: A variable optical attenuator device is provided for modulating an optical signal. The attenuator device includes a variable attenuation assembly with an electrochromic structure interposed between a first electrode and a second electrode. The electrochromic structure is configured to reversibly change its optical characteristics from a bleached off state to a colored active state under the influence of an electrical potential applied to the first and second electrodes to thereby modulate the optical signal. The optical attenuator device includes at least one lens attached to the variable attenuation assembly. The lens cooperates with the variable attenuation assembly to direct the optical signal towards the electrochromic structure. Waveguides such as optical fibers define ports at the outer endface of the lens for the optical signal.

Abstract: An optical waveguide network is formed in a substrate of an electrooptically active material. The optical waveguide has input and output facets where optical signals may be input to and output from the integrated optics chip. At least one lateral trench is formed in the substrate. The lateral trench is arranged to prevent light rays incident thereon from inside the substrate from propagating to the output facet. The lateral trench may be formed as a slot that extends toward the surface of the substrate where the optical waveguide network is formed, or the trench may be parallel to the plane of the optical waveguides.

Abstract: The present invention provides an active semiconductor optical switch for a 1×N interconnect switch having an input light channel, a plurality of output light channels, and a steering section coupled between the input and output channels. The steering section selectively directs an input light signal from the input light channel to an M number of the plurality of output light channels, where M ranges from one to the total number of output light channels of the plurality. The steering section includes transversely-spaced first and second elongate electrical contacts and an elongate slab waveguide extending therebetween. The slab waveguide is formed from a material having an optical refractive index responsive to a first electrical current applied to the first electrical contact and a second electrical current applied to the second electrical contact.

Abstract: A semiconductor integrated circuit which has a wavelength converting function and a wavelength demultiplexing function is made up of a relatively small number of parts, allows parts to be integrated easily, and can be manufactured at a relatively low cost. The semiconductor integrated circuit includes an MMI waveguide for converting an optical signal having a second wavelength into an optical signal having a first wavelength, a first input port mounted on an entrance end of the MMI waveguide, for being supplied with the optical signal having the first wavelength, a second input port for being supplied with the optical signal having the second wavelength, and at least one output port mounted on an exit end of the MMI waveguide, for extracting the optical signal having the first wavelength. The MMI waveguide has a refractive index variable depending on the intensity of the optical signal having the second wavelength.

Abstract: The present invention uses a single substrate to provide a small-size optical waveguide element that requires no optical axis adjustments, can be driven at a low voltage, is excellent in light utilization efficiency, and can rapidly two-dimensionally deflect a light beam. A right-triangle upper electrode and a rectangular transparent upper electrode are formed on top of a thin-film optical waveguide formed on a conductive substrate to serve as a lower electrode, and an emission right-angled prism is secured on top of the transparent upper electrode. A voltage is applied between the upper electrode and the conductive substrate, and between the transparent upper electrode and the conductive substrate. A horizontal deflection is performed upon application of a voltage to the upper electrode and a vertical deflection is performed upon application of a voltage to the transparent upper electrode.

Abstract: An optical intensity modulator is disclosed which comprises a waveguide containing a core adjacent to at least one cladding layer and exhibits a refractive index n(core) different from the refractive index n(cl) or the cladding layer, where the waveguide is a bent channel waveguide and the intensity modulator contains a heater or cooler for altering the temperature at or near the bend. The core and the cladding layer exhibit different thermo-optic coefficients at the bend such that the contrast between n(core) and n(cl) can be changed by altering the temperature. The optical intensity modulator is more compact in size and more efficient with regard to energy consumption. The invention also pertains to thermo-optic switches and thermo-optic cascaded switches comprising the optical intensity modulator and to the use of the optical intensity modulator as a tunable attenuator.

Abstract: A wavelength characteristic control device capable of variably controlling a wavelength characteristic in a satisfactory manner. A polarized light wavelength characteristic changing element has a wavelength characteristic such that the transmittances or reflectances of P- and S-polarized rays vary differently with respect to wavelength. Polarization variable control means subjects the plane of polarization of the polarized light incident on the polarized light wavelength characteristic changing element to rotatory control to change the ratio of the P-polarized ray to the S-polarized ray, thereby variably controlling the wavelength characteristic.

Abstract: An optical waveguide sensor having high refractive index sensitivity over a range of ambient refractive indices is provided. The sensor comprises a core having at least one long period gating disposed therein. An inner and outer cladding region, each cladding region having an effective refractive index. The total effective refractive index of the inner cladding region and the outer cladding region is approximately equal to but not greater than the effective refractive index of an environmental parameter to be sensed. These optical waveguide sensors are useful for measuring changes in a variety of environmental parameters.

Abstract: A diffraction grating for a waveguide or for externally incident light. The grating includes a substrate and an electrooptic structure extending over it. The electrooptic structure may include a waveguide having a propagation axis. A first and a second electrode structure are provided on either side of the electrooptic structure so that an electric field is generated in the electrooptic structure when a potential is applied to the electrodes. The first electrode structure has an interdigitated configuration defining a plurality of fingers. In use, respective potentials V0 and V0+&Dgr;V are applied to adjacent fingers. The diffraction grating induced in the electrooptic structure by the periodic electric field advantageously has a refractive index adjustable by varying V0 and &Dgr;V and a spatial periodicity adjustable by varying &Dgr;V.

Abstract: An optical pulse generator having a high order transfer function that comprises a first and a second nested interferometric modulator, each modulator comprising an optical input, an electrical input, a first arm, a second arm and an optical output. The second interferometric modulator is optically coupled into the second arm of the first interferometric modulator. The optical output of the first interferometric modulator generates pulses at a repetition rate that is proportional to a multiple of a frequency of an electrical signal applied to the electrical input of at least one of the first and second interferometric modulator and at a duty cycle that is inversely proportional to the order of the transfer function of the optical pulse generator. The multiple may be any integer equal to or greater than one.

Abstract: The invention relates to modulator of the Mach-Zehnder type in which an optical wave source is coupled to an optical waveguide separating through a coupler (2) into two branches (B1, B2) which recombine, the branches being respectively provided with electro-optical modulators (4). According to the invention, the coupler (2) has an adjustable coupling ratio, regulation means being provided for adjusting the said coupling ratio following the application of at least one signal (V) to at least one of the electro-optical modulators (4) so that the output optical powers of the branches (B1, B2) are respectively equal for destructive interference conditions and for constructive interference conditions. These regulation means comprise at least one regulation electrode (5). The invention applies principally to optical signal transmission systems.

Abstract: Disclosed herein is an optical modulator including an optical waveguide structure for converting an input beam into first and second output beams, an electrode for applying an electric field to the optical waveguide structure, so as to switch between a first mode where the input beam is converted into the first output beam and a second mode where the input beam is converted into the second output beam, first and second photodetectors for detecting the powers of the first and second output beams, respectively, and a bias circuit for applying a bias to the electrode so that the ratio in output level between the first and second photodetectors becomes constant. With this configuration, an operation point can be stabilized without the need for superimposition of a low-frequency signal, thereby suppressing intersymbol interference.

Abstract: An optical waveguide, such as a rib waveguide, having a first portion (7) to which a dopant (9) and/or a metal layer (10) is applied to enable an optical property of a second portion of the waveguide to be altered, the first portion (7) having a structure, e.g. being corrugated, the geometry of which is such as to prevent an optical wave being carried in the first portion (7). The dopant (9) and/or metal layer (10) can thus be positioned close to the second portion which carries the optical wave without causing perturbation, e.g. attenuation and/or polarization, of the optical wave.

Abstract: A high-performance electro-optic intensity modulator using two polymeric waveguides having a high extinction-ratio modulation process is implemented by the coupling-out effect of induced grating modulation. The two waveguides can be either single-mode or multi-mode, even highly multimode. The inducing of a modulated grating-coupler in a waveguide channel makes the coupling between two waveguides become unidirectional and the coupling efficiency can be achieved to a very high value in theory. The two waveguide channels in this intensity modulator may have large dimensions, so the device can support either single-mod or multi-mode operation. The electro-optic waveguide intensity modulator may be used either as a single optical modulator/switch or as a waveguide modulator/switch array for fiber-optic communication.

Abstract: A wavelength selective optical fiber coupler having various applications in the field of optical communications is disclosed. The coupler is composed of dissimilar waveguides in close proximity. A light induced, permanent index of refraction grating is recorded in the coupler waist The grating filters and transfers energy within a particular range of wavelengths from a first waveguide to a second waveguide. Transversely asymmetric gratings provide an efficient means of energy transfer. The coupler can be used to combine or multiplex a plurality of lasers operating at slightly different wavelengths into a single fiber. Other embodiments such as a dispersion compensator and gain flattening filter are disclosed.

Abstract: Apparatuses, methods, and systems are disclosed for controlling optical signal wavelength spacing by providing for simultaneous upconversion of a plurality of electrical signal on subcarrier frequencies of an optical carrier frequency with or without modulation of an electrical data signal onto the optical carrier frequency. The optical carrier lightwave is split into a plurality of split lightwaves upon which one or more electrical frequencies carrying information can be upconverted onto optical subcarriers of the lightwave carrier frequency. The relative spacings of the optical subcarrier lightwaves will thus be unaffected by variation in the carrier frequency. The optical subcarrier lightwaves can then be recombined to form the optical data signal carrying the plurality of information carried by the electrical frequencies.

Abstract: Tunable add/drop optical device for injecting or extracting (add/drop) at least a selected optical channel or carrier wavelength in or from a set of multiplexed channels or carriers of different wavelengths comprising a plurality of directional couplers (AD1 . . . AD6) and a plurality of phase-shift stages (SF1 . . . SF5) alternately connected in cascade, wherein each phase-shift stage defines a certain optical path length difference (&Dgr;L1 . . . &Dgr;L5) between two distinct optical paths of the stage. The tuning is performed modifying the refraction index of one path of said phase shift stages by means of Joule effect heating strips (L1 . . . L5) or by means of metallic field plates adapted to receive a signal suitable to modify the electric field intensity.

Abstract: The device comprises an upper silicon layer (10) including two optically connected rib waveguides (3,4) formed in the upper silicon layer (10); a pair of dissimilar materials (6,7) each positioned between the two waveguides (3,4); and an electrical circuit (8,9,13) through the pair of dissimilar materials (6,7), so that an electrical current can be passed through the dissimilar materials (6,7) in both forward and reverse directions, so as to simultaneously heat one waveguide and cool the other waveguide by virtue of the Peltier effect.