Abstract: In one embodiment, an apparatus includes a passive element including one or more first waveguides and one or more second waveguides. The apparatus also includes an active element integrated into the passive element. The active element includes one or more third waveguides that actively guide light from the first waveguides to the second waveguides. The third waveguides include polarization-independent electro-optical (EO) thin film.

Abstract: An optical transceiver for including an electrical connector with a serial interface for coupling with an external electrical cable or information system device, a fiber optic connector adapted for coupling with an external optical fiber, and an electro-optical subassembly for converting between an information containing electrical signal and a modulated optical signal corresponding to the electrical signal including a transmitter subassembly including at least first and second lasers operating at different wavelengths and modulated with respective first and second electrical signals for emitting first and second laser light beams, and an optical multiplexer for receiving the first and second beams and multiplexing the respective optical signals into a single multi-wavelength beam.

Abstract: In an aspect of the present invention, a thermo-optic phase shifter includes a substrate, a heater, a clad layer formed directly or indirectly on a substrate, an optical waveguide clad layer formed apart from the substrate and the clad layer in a portion corresponding to the heater, and a core layer provided inside said bridge section clad layer. The optical waveguide clad layer is connected with the clad layer in a portion of the phase shifter other than the heater corresponding portion. The optical waveguide clad layer and the core layer form an optical waveguide in the heater corresponding portion. The heater is provided inside or outside the optical waveguide apart from the core layer in the heater corresponding portion, and generates heat to change a phase of a light signal propagated in the optical waveguide.

Abstract: The present invention provides systems and methods for measuring signal phase shift caused by changes in fiber length.

Abstract: An optical transceiver for including an electrical connector with a serial interface for coupling with an external electrical cable or information system device, a fiber optic connector adapted for coupling with an external optical fiber, and an electro-optical subassembly for converting between an information containing electrical signal and a modulated optical signal corresponding to the electrical signal including a transmitter subassembly including at least first and second lasers operating at different wavelengths and modulated with respective first and second electrical signals for emitting first and second laser light beams, and an optical multiplexer for receiving the first and second beams and multiplexing the respective optical signals into a single multi-wavelength beam.

Abstract: An apparatus and method for controlling an optical interferometer are provided. The method includes setting a thermoelectric cooler (TEC) temperature of the optical interferometer to a room temperature, obtaining an optimal temperature using a difference between two output powers of the optical interferometer based on eye opening of the two output powers and applying an optimal heat voltage generating the optimal temperature to a delay adjuster of the optical interferometer, and performing dithering at the optimal temperature to stabilize the optimal heat voltage.

Abstract: An optical interference unit branching inputted input light into two optical waveguides, combining the respective branched lights propagating through the respective optical waveguides and outputting modulated light is included, and bias voltage supplied to at least one optical waveguide out of the two optical waveguides is controlled in accordance with wavelength of the input light. Further, a phase of the modulated light is controlled by phase adjusting voltage in accordance with the wavelength of the input light.

Abstract: Propagation delay variations for a distributed optical modulator driver are described. In one example, a system includes a signal distribution network, a plurality of output driver stages coupled to the signal distribution network, a waveguide coupled to the outputs of the output drive stages to receive a voltage across the waveguide, and a plurality of delay cells between the distribution network and the plurality of output driver stages to apply a differential delay to the output stages.

Abstract: Methods and apparatus for optical isolation in high peak power fiber-optic systems prevent damage to a facet within a fiber-optic isolator caused by back-reflected light from, for example, an optical amplifier. Preventing damage to the facet may include expanding a mode area of the back-reflected light and/or reducing a change in refractive index.

Abstract: A wavelength selective switch device is disclosed that includes an elongated signal communication path extending from a first end of the device to a second end of the device. The signal communication path extends through a plurality of regions of varying indices of refraction, and the plurality of regions includes adjustable regions that are each coupled to an adjustable voltage source for changing a voltage potential across each of the adjustable regions such that the index of refraction of said adjustable regions may be changed by changing the voltage potential across each adjustable region.

Abstract: The present invention is directed toward an optical device and a drive voltage supply device, which prevent occurrence of a DC drift and enable stable selection of light of desired wavelength without deteriorating a filtering characteristic. The optical device comprises a substrate having an electrooptical effect; an optical waveguide formed in this substrate; a plurality of comb electrode pairs which are arranged side by side along the optical waveguide, can apply an electric field for said electrooptical effect, and are formed from respective pairs of comb electrodes; and drive voltage supply means capable of supplying a drive voltage to said comb electrode pairs such that the voltage changes with time.

Abstract: Provided is an optical module including a microstrip line, a traveling wave type optical device positioned in the end of the microstrip line, and at least one balanced open stub connected to the microstrip line for the impedance matching at a specific frequency such as 40 GHz and 60 GHz. For the fine tuning, laser trimming can be applied to the stub. A transition region is formed between the optical device and the microstrip line. A termination resistor is formed to face the microstrip line with the optical device therebetween. A bandwidth can be controlled at a specific frequency by adjusting a number of the stubs or a value of the termination resistor.

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: Methods and apparatus for reducing noise in optical apparatus comprising a delay line by utilizing a plurality of wavelength specific delay lines to delay an input waveform such as a pulse rather than a single delay line. In a preferred embodiment an apparatus is configured to generate an optical waveform by distributing an input optical waveform among a plurality of environmentally isolated legs, wherein each leg contributes to the generated optical waveform by reflecting back at least a portion of light distributed to the leg, and the distribution among the plurality of legs is at least partially wavelength dependent.

Abstract: A waveguide for use in polarization mode converters and polarization modulators using extrinsic strain to prerotate the principal axes and control birefringence is disclosed herein. The invention relates to the orienting of principal propagation axes in an optical waveguide by pre-stressing the waveguide, using an extrinsic stress, to re-orient the principal propagation axes from an unstressed orientation to a substantially ideal orientation. The waveguide is preferably stressed by an extrinsic strain inducer which applies a shear force to the waveguide to induce anisometry in the waveguide structure.

Abstract: An optical pulse time spreader which can generate a chip pulse string of which intensity is equalized. The reflectances R1, R2 and Rk of the first, second and k-th (k is an integer which satisfies 3?k?J) unit FBG are given by the following formulae respectively. R1=Pc(constant) ??(a) R2=Pc/(1?R1)2 ??(b) Rk=(Pc1/2?Pk1/2)2/{(1?R1)2·(1?R2)2 . . . (1?Rk-1)2} ??(c-1) Rk=(Pc1/2+Pk1/2)2/{(1?R1)2 ·(1?R2)2 . . . (1?Rk-1)2} ??(c-2) Here Pc is an arbitrary constant, and Pk is an intensity of a triple reflection chip pulse which is output for the k-th time. The formulae (c-1) and (c-2) are the reflectance of the k-th unit diffraction grating when the phase difference between the single reflection chip pulse, which is output for the k-th time, and the triple reflection chip pulse, which is output for the k-th time, is 0 and ? respectively.

Abstract: An integrated active electrical waveguide is described for optical waveguide modulators. The active waveguide may include an optical waveguide, a plurality of modulators integrated into the waveguide to modulate the index of refraction of the waveguide, and a plurality of local amplifiers, each coupled to a modulator.

Abstract: A method, apparatus and system for minimally intrusive fiber identification includes imparting a time-varying modulation onto an optical signal propagating in an optical fiber and subsequently detecting the presence of the time-varying modulation in the optical signal transmitting through the fiber to identify the fiber. In a specific embodiment of the invention, a time-varying curvature is imposed on the fiber to be identified and the presence of the resultant time variation in the transmitted power of a propagating optical signal is subsequently detected for identification of the manipulated fiber.

Abstract: According to embodiments of the present invention, an optical waveguide includes a high dielectric constant core material relative to the cladding material. The cladding material has an index of refraction that is adjustable in response to an electrical stimulus.

Abstract: An apparatus for determining V? of an optical modulator includes an RF source that generates a variable power RF modulation signal for modulating an optical modulator. An optical detector detects a modulated optical signal generated by the optical modulator and generates an electrical detection signal in response to the detected modulated optical signal. An RF power meter measures an RF detection signal power to determine a minimum RF detection signal power, an RF modulation signal power corresponding to the minimum RF detection signal power being used to calculate V? of the optical modulator.

Abstract: An apparatus and method for high speed phase modulation of optical beam. For one embodiment, an apparatus includes an optical waveguide having adjoining first and second regions disposed in semiconductor material. The first and second regions have opposite doping types. A first buffer is disposed along the optical waveguide. A first higher doped region of semiconductor material is also included outside an optical path of the optical waveguide. An inner portion of the first higher doped region is adjoining and coupled to the first region of the optical waveguide. An outer portion of the first higher doped region is adjoining the first buffer. The first higher doped region has a higher doping concentration than a doping concentration within the optical path of the optical waveguide. A first contact having an inner portion adjoining and coupled to the first higher doped region is also included. The first contact has an outer portion adjoining the first buffer.

Abstract: A method of modulating an optical carrier. A target carrier modulation is computed based on an input data signal. An effective length of an optical modulator is then controlled based on the target carrier modulation.

Abstract: Laser light emitted from a vertically confined surface emitting laser (VCSEL) is incident on a side surface near an end region of an optical waveguide. The end region of the optical waveguide is processed by polishing to taper at an angle of 45 degrees, and an optical modulator is formed on the polished surface. The optical modulator is a Fabry-Perot modulator using a linear electro-optical effect. The modulator has a thick transparent electro-optical layer which is deposited by using an aerosol deposition method.

Abstract: A method and arrangement for stimulated Brillouin scattering (SBS) reduction in optical media that generate SBS are provided. SBS is reduced by providing a plurality of segments of optical medium and providing an optical isolator between adjacent pairs of segments so as to reduce the SBS and thereby improve power throughput. The isolators prevent backward propagation of an SBS signal between the adjacent segments. A wavelength multiplier, a wavelength converter and a multi-wavelength laser source, which include the arrangement, are also provided.

Abstract: An optical transmitter includes a modulator, a dispersion adjustment module, and an optical amplifier. The optical transmitter is configured to transmit optical pulses over a free-space optical communication channel. The modulator is configured to produce an optical carrier that is amplitude and/or phase modulated by data. The dispersion adjustment module is connected between the modulator and the amplifier and is configured to substantially change temporal widths of optical pulses received from the modulator by changing dispersions of the received optical pulses.

Abstract: In one embodiment, an apparatus for a high data-rate optical modulator bias circuit is disclosed. The apparatus comprises an optical modulator, a voltage-controlled voltage source to translate a control voltage into a voltage referenced to a voltage supply to the optical modulator, a buffer amplifier with high current sinking capability to supply a bias voltage to the optical modulator, and a bias-T to couple the bias voltage to a data port of the optical modulator. Other embodiments are also described.

Abstract: An optical waveguide has a surface. An array of separately actuated bodies is disposed proximal to the exposed surface, and an actuator separately actuates at least some of the bodies to change a spectral characteristic of a wave propagating through the waveguide. Preferably, the bodies are metal striplines, an electro-optical material is disposed between the striplines and the exposed surface, and the actuator is a CMOS chip that imposes a voltage to some or all of the lines. The voltage changes the refractive index at the interface with the surface, changing an index of refraction profile of the waveguide and effectively imposing a grating. Alternatively, the bodies are micro-beams and the actuator, also controlled by a CMOS chip, separately moves each micro-beam into and out of proximity to the surface. The grating is programmable via the CMOS chip.

Abstract: A first embodiment of the invention provides a Gires-Tournois etalon (DGTE) 20 comprising a cladding mode suppressed optical fibre 22, including an etalon section 24 in which a weakly reflective optical waveguide grating 26 and a strongly reflective optical waveguide grating 28 are provided. The two gratings 26, 28 are chirped fibre Bragg gratings (FBGs). The chirped FBGs 26, 28 are arranged to together define an etalon cavity. Another aspect of the invention provides a dispersion compensator 60 comprising two DGTEs 62, 64 according to the first embodiment of the invention. The DGTEs 62, 64 have a linearly varying dispersion over a selected optical bandwidth. The first DGTE 62 has a positive dispersion slope and the second DGTE 64 has a negative dispersion slope. The magnitudes of the dispersion slopes of the two DGTEs 62, 64 are substantially equal, so that the dispersion compensator 60 has a constant dispersion across the selected bandwidth.

Abstract: An optical fiber interferometer (10) with relaxed loop tolerance, and a quantum key distribution (QKD) system (200) using same is disclosed. The interferometer includes two optical fiber loops (LP1 and LP2). The loops have an optical path length (OPL) difference between them. A polarization-maintaining (PM) optical fiber section (60) of length (L60) and having fast and slow optical axes (AF and AS) optically couples the two loops. The length and fast-slow axis orientation is selected to introduce a time delay (?T1-2) between orthogonally polarized optical pulses traveling therethrough that compensates for the OPL difference. This allows for drastically relaxed tolerances when making the loops, leading to easier and more cost-effective manufacturing of the interferometer as well as related devices such as a optical-fiber-based QKD system.

Abstract: A method of appropriately adjusting a bias signal of an optical modulator is provided. For an optical modulator provided with a first sub Mach-Zehnder waveguide, a second sub Mach-Zehnder waveguide and a main Mach-Zehnder waveguide, a predetermined signal is supplied to the main Mach-Zehnder waveguide, and bias signals supplied to the first and second Mach-Zehnder waveguides are adjusted so as to lower an amplitude of an output light of the main Mach-Zehnder waveguide.

Abstract: An optical modulator includes at least one waveguide medium that receives light. An absorption medium absorbs the light under predefined conditions and outputs optically modulated light. The absorption medium is comprised of a Ge-based structure. The Ge-based structure uses the Franz-Keldysh effect to create said optically modulated light.

Abstract: An optical SSB modulator capable of appropriately adjusting a phase difference of light in the MZ waveguides and automatically adjusting a voltage impressed to the bias adjustment electrodes is provided. The above-mentioned object is achieved by an optical SSB modulator (1) provided with a first sub Mach-Zehnder waveguide (MZA) (2), a second sub Mach-Zehnder waveguide (MZB) (3), a main Mach-Zehnder waveguide (MZC) (4), a first bias adjustment electrode (DCA electrode) (5), a second bias adjustment electrode (DCB electrode) (6), a first modulation electrode (RFA electrode) (7), a second modulation electrode (RFB electrode) (8) and a third bias adjustment electrode (DCC electrode) (9), wherein either one of or both of output portions (10, 11) of the MZA and the MZB have an X-branching form, and specifically having one of light paths of the X-branching connected to a photodetector.

Abstract: Embodiments of the invention provide an electro-absorption modulator including an optical waveguide and a microwave waveguide. The microwave waveguide is electromagnetically coupled to the optical waveguide. The optical waveguide includes a quantum well region and a substantially sinusoidal structure. The waveguide mode of the optical waveguide is responsive to the substantially sinusoidal structure.

Abstract: A single side band modulation device includes a first Mach Zehnder interferometer and a second Mach Zehnder interferometer. The first Mach Zehnder interferometer includes at least two output arms, and the second Mach Zehnder interferometer includes at least two output arms. Terminals of the output arms are connected with one another.

Abstract: An optical modulator structure includes a block that includes electro-optical (EO) materials. A waveguide and electrode structure is formed on a substrate. The block is in close proximity to the waveguide and electrode structure so as to form optical modulation when electric fields in the block are varied.

Abstract: A compensator for compensating polarisation-mode dispersion, comprises a splitter (30) arranged to split light, according to the light's polarisation, between a first optical path and a second optical path; a combiner (40) arranged to combine light from the first optical path and the second optical path, and a monitor (15) for monitoring the light. An active wavelength-delay device (70) is provided in the first optical path and arranged such that components of the light travelling in the first optical path and having different wavelengths are subjected to different delays, the delays being selected according to an output from the monitor (15).

Abstract: A polarization-shaped duobinary optical transmission apparatus is disclosed. The apparatus includes a light source that generates light having a continuous wave, an optical intensity modulator that converts the light into an optical intensity signal based upon an input electric signal and a differential encoder that encodes the input electric signal. The apparatus also includes a delay element that delays the encoded electric signal and a polarization-shaped modulator that polarization-modulates the signal modulated optical intensity by using the delayed signal.

Abstract: The device comprises an optical waveguide and an acoustic wave generating device. The waveguide has an optical band gap and a sharp electronic transition (e.g. an excitonic transition) in the band gap, and the acoustic wave generating device generates acoustic waves within the waveguide. Light passing through the waveguide is of a frequency within the band gap of the waveguide and is nearly resonant with the sharp electronic transition. The wave generating device is arranged to generate acoustic waves so as to induce optical band gas in the polariton spectrum, thereby affecting the transmission of the light passing through the waveguide, the transmission of which is thereby affected.

Abstract: An electromagnetic field sensing apparatus includes an optical modulator, a miniature antenna for sensing the electromagnetic field, a light source, a first optical fiber, an optical detector and a second fiber. The optical modulator can vary the amplitude of a light beam propagating therethrough in response to an electric field intensity. The miniature antenna for sensing the electromagnetic field can sense both the electric field intensity and the magnetic field intensity of an electromagnetic field and apply an electric voltage to the optical modulator in response to the sensed electromagnetic field intensity. The light source is used to generate a light beam, the first optical fiber is used for transmitting the light beam to the modulator, and the second fiber is used for transmitting the light beam from the modulator to the optical detector.

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

Abstract: The present invention provides an optical modulation element module capable of stably operating for long periods without limiting the operating conditions. An optical modulation element module comprising an optical modulation element 12, a case 11 with said optical modulation element being integrated thereto, input output fibers 13, 14 being connected to said optical modulation element and also guided to an exterior of said case, a terminal for introducing a modulating signal and a bias adjustment voltage that are to be applied to said optical modulation element, said case being hermetically sealed, is characterized in that said case 11 is made of a material having almost the same coefficient of linear expansion as the optical modulation element 12, said optical modulation element is affixed to said case by using a thermoplastic and high-elastic adhesive material 19, a linear expansion difference between each material of said case and said fiber is less than 16×10?6/° C.

Abstract: A doped barrier region included in an optical phase shifter is disclosed. In one embodiment, an apparatus according to embodiments of the present invention includes a first region of an optical waveguide and a second region of the optical waveguide. The second region of the optical waveguide includes a higher doped region of material and a lower doped region of material. An insulating region disposed between the first and second regions of the optical waveguide is also included. A first portion the higher doped region is disposed proximate to the insulating region. A dopant barrier region is also included and is disposed between the higher and lower doped regions of the second region of the optical waveguide.

Abstract: The present invention provides a RF-lightwave modulator with improved efficiency by making use of a broken loop resonator having a gap therein. In the present invention a RF input signal is coupled into a broken loop resonator, thereby producing a RF output signal. An optical modulator connected across the gap receives the RF output signal and modulates a lightwave with the RF output signal to produce a RF modulated lightwave. Because the optical modulator is connected across the gap in the broken loop resonator, the voltage of the RF output signal applied to the optical modulator will be greater than the voltage of the RF input signal applied to the broken loop resonator.

Abstract: The invention relates to an integrated optics coupling element that includes a substrate, an optical guide core, an optical cladding independent of the core and surrounding at least one portion of the core in a zone of the substrate called the zone of interaction. The cladding has at least in the zone of interaction a modulation of its structure so as to form a grating. The refractive index of the cladding is different from the refractive index of the substrate and lower than the refractive index of the core at least in the part of the cladding next to the core in the zone of interaction. Embodiments of the invention may be used to make gain flatteners for optical amplifiers or to make linear response filters whose wavelength is on a spectral band.

Abstract: The present invention provides silicon based thin-film structures that can be used to form high frequency optical modulators. Devices of the invention are formed as layered structures that have a thin-film dielectric layer, such as silicon dioxide, sandwiched between silicon layers. The silicon layers have high free carrier mobility. In one aspect of the invention a high mobility silicon layer can be provided by crystallizing an amorphous silicon layer. In another aspect of the invention, a high mobility silicon layer can be provided by using selective epitaxial growth and extended lateral overgrowth thereof.

Abstract: The present invention provides a highly-integrated and compact optical element and further provides an optical element having various functions such as lower driving voltage, chirping suppression and polarization-independency. The optical element comprising a substrate 1 consisting of a material having an electrooptic effect, top optical waveguides 2-1 an 2-2 formed on the top face of said substrate, bottom optical waveguides formed on the bottom face of said substrate, a top modulating electrode for controlling the phase of a light wave being propagated through said top optical waveguide, and a bottom modulating electrode for controlling the phase of a light wave being propagated through said bottom optical waveguide, is characterized in that at least one side edge of said substrate comprises output and input of said optical waveguides formed on said top and bottom faces, and a turnback element is located adjacent to said one side edge to guide the light wave from said output to said input.

Abstract: Traveling-wave optoelectronic wavelength conversion is provided by a monolithic optoelectronic integrated circuit that includes an interconnected traveling-wave photodetector and traveling-wave optical modulator with a widely tunable laser source. Either parallel and series connections between the photodetector and modulator may be used. An input signal modulated onto a first optical wavelength develops a traveling wave voltage on transmission line electrodes of the traveling-wave photodetector, and this voltage is coupled via an interconnecting transmission line of the same characteristic impedance to transmission line electrodes of the traveling-wave optical modulator to modulate the signal onto a second optical wavelength derived from the tunable laser. The traveling wave voltage is terminated in a load resistor having the same characteristic impedance as the photodetector and modulator transmission lines.

Abstract: An optical waveguide module includes a light emitting element which outputs light, a light receiving element which monitors an output of the light emitting element, and an optical waveguide film having a waveguide core which has a notched portion having an optical path changing surface that changes an optical path of part of the light. The light emitting element is coupled to an end portion of the optical waveguide film, and the light receiving element is provided to face a position of the optical waveguide film from where the part of the light whose optical path has been changed by the optical path changing surface exits.

Abstract: An optical modulator which has substantially low loss and has an improvement in voltage reduction is disclosed having an electro-optic lithium niobate substrate. The substrate has first, second and third ridges extending along its surface. Extending along the first and second ridges are first and second waveguides. A first RF electrode extends over the first waveguide and a second slotted electrode including a first section extends over the second waveguide. A second section of the slotted extends parallel to and adjacent to the first section on the third ridge. In summary, this invention provides a slotted ground electrode wherein a slot is formed in the substrate between the slotted electrode.

Abstract: An arrangement for removing unwanted amplitude modulation from the output of an electro-optic phase modulator (formed within a silicon-on-insulator (SOI) system) includes resonant filters that are biased on the positive and negative slopes of the response signal. Therefore, as the amplitude response of one filter decreases, the amplitude response of the other filter increases, resulting in balancing the output and essentially eliminating amplitude modulation from the phase-modulated output signal. In one embodiment, ring resonators (formed in the SOI layer) are used to provide the filtering, where as the number of resonators is increased, the performance of the filtering arrangement is improved accordingly.