Abstract: A delay-line demodulator for demodulating a differential quadrature phase shift keying (DQPSK) signal is provided. The demodulator includes two Mach-Zehnder interferometers individually comprising two waveguides having different lengths therebetween and through which a light signal branched from the DQPSK signal propagates, respectively. A phase of the light signal propagating at one of the waveguides is delayed as compared to a phase of the light signal propagating at another one of the waveguides, wherein a divergence amount of polarization is adjusted by driving sets of heaters that are facing each other and sandwiching a half wavelength plate therebetween.

Abstract: This invention provides a balanced thermal approach to the tuning of an optical time delay device in order to eliminate any long-term time response of the device performance due to thermal time constants of the device, its mount, packaging or electronic temperature control circuits. The invention provides multiple ways to improve the thermal tuning speed of the balanced thermal approach. Additionally, the invention overcomes an issue of microresonator non-uniformity by operating a large group of microresonators as a ‘super-ring’ by tuning the large group together to provide a controllable group delay with large bandwidth.

Abstract: An optical switch comprises a plurality of input ports and a plurality of out port ports; a plurality of displaceable optical elements for directing beams from a selected input to a selected output; wherein the number of displaceable elements substantially corresponds to either the number of input ports or the number of output ports.

Abstract: To provide a light control device which is possible to realize a velocity matching between a microwave and an optical wave or an impedance matching of microwaves even through a signal oath having a high impedance of 70? or more, and is possible to reduce a driving voltage.

Abstract: A method for generating a carrier residual signal and its device, in which a heterodyne optical signal used in a photometric field or an optical fiber radio communication field can be stably generated with a simplified structure. The device includes an optical modulating unit that includes a light source generating a light wave having a specific wavelength, and an SSB optical modulator. A light wave emitted from the light source enters into the optical modulating unit. A light wave emitted from the optical modulating unit includes a carrier component related to a zero-order Bessel function and a specific signal component related to a specific high-order Bessel function while suppressing signal components other than the specific signal component related to the specific high-order Bessel function, and a ratio of optical intensity between the carrier component and the specific signal component is set substantially to 1.

Abstract: In one embodiment, the apparatus includes a substrate having a surface and an optical waveguide having a ridge-shaped semiconductor optical core, the ridge-shaped semiconductor optical core being located over the surface. The apparatus may further include a first semiconductor slab being in contact with a first portion of the ridge-shaped semiconductor optical core, and a second semiconductor slab being in contact with a second portion of the ridge-shaped semiconductor optical core, the second semiconductor slab being farther from the surface than the first semiconductor slab.

Abstract: The present invention provides a contact-type solid-state imaging apparatus which realizes high resolution and high sensitivity, and also implements downsizing and lowering the cost of the contact-type solid-state imaging apparatus. Each pixel includes a protection glass plate, a light-collecting device, a light-receiving device, a semiconductor integrated circuit, a light emitting diode (LED) and a mounting package. The light-collecting apparatus has two kinds of distributed index lens (o lens and convex lens), and Sin (N=2) film, which is a two-stage concentric structure, is embedded in SiO2 (N=1.45) film.

Abstract: There is provided in one of the embodiments of the disclosure a lithium niobate modulator structure for mitigating DC bias drift comprising a highly doped semiconductor layer patterned above an optical waveguide having one or more DC sections and an RF section, wherein a metal layer or contact is in contact with a portion of the semiconductor layer and a buffer layer is deposited in the RF section. There is provided in another embodiment of the disclosure a method for making a lithium niobate electro-optical modulator for mitigation of DC bias drift.

Abstract: A method for operating an optical transmitter for transmission of an optical signal over a dispersive fiber optic media to a remote receiver. The method includes the steps of providing a respective bias level of a first RF signal and a second RF signal input to an optical modulator that modulates the optical signal; determining an output level of the optical modulator in response to the provided bias levels and adjusting a bias level of at least one of the first and second RF input signals based upon the determined output level and an expected output level at a configuration set point for the provided respective bias levels.

Abstract: An example photodetector includes a waveguide structure having an active waveguide comprising an absorber for converting photons conveying an optical signal into charge carriers conveying a corresponding electrical signal; a carrier collection layer for transporting the charge carriers conveying the electrical signal; and a secondary waveguide immediately adjacent to the carrier collection layer, for receiving the photons to be detected, and which is evanescently coupled to the active waveguide.

Abstract: Embodiments of an optical device, an array of optical devices, and a technique for fabricating the optical device or the array are described. This optical device is implemented on a substrate (such as silicon), and includes a thermally tunable optical waveguide that has good thermal isolation from its surroundings. In particular, a portion of a semiconductor in the optical device, which includes the optical waveguide, is free standing above a gap between the semiconductor layer and the substrate. By reducing the thermal coupling between the optical waveguide and the external environment, the optical device can be thermally tuned with significantly less power consumption.

Abstract: An all-fiber optical pulse compression arrangement comprises a concatenated arrangement of a section of input fiber (e.g., a single mode fiber), a graded-index (GRIN) fiber lens and a section of pulse-compressing fiber (e.g., LMA fiber). The GRIN fiber lens is used to provide mode matching between the input fiber (supporting the propagation of chirped optical pulses) and the pulse-compressing fiber, with efficient pulse compression occurring along the length of the LMA fiber. The dispersion and length of the LMA fiber section are selected to provide the desired degree of pulse compression; for example, capable of reconstituting a femtosecond pulse as is used in supercontinuum generation systems.

Abstract: A system for dynamic waveform shaping in an optical fiber comprising: the optical fiber receiving an optical waveform, the optical waveform having individual spectral lines; a plurality of fiber bragg gratings in-line on the optical fiber, each having a reflectivity wavelength corresponding to one of the spectral lines; a plurality of polarization controllers in-line on the optical fiber, each polarization controller receiving the optical waveform from a respective fiber bragg grating; a circulator for directing the optical waveform as input to the plurality of fiber bragg gratings and receiving the optical waveform as output from the plurality of fiber bragg gratings; and a polarizer in-line on the optical fiber receiving the optical waveform from the fiber bragg gratings and the polarization controllers.

Abstract: The invention relates to an electro-optic modulator structure containing an additional set of bias electrodes buried within the device for applying bias to set the operating point. Thus the RF electrodes used to modulate incoming optical signals can be operated with zero DC bias, reducing electrode corrosion by galvanic and other effects that can be present in non-hermetic packages. The bias electrodes are at least partially separated from the substrate with a buffer layer, which in one embodiment has a small amount of conductivity. This conductive buffer layer reduces optical loss from the bias electrodes and also reduces DC drift.

Abstract: A laser system includes a multimode fiber (MMF) receiving a single-mode input beam and a mechanical oscillator coupled to the MMF. The oscillator is operative to modulate a phase of interference wave by periodically extending the fiber total length at such a frequency that a cross-coupling coefficient between fundamental and at least one high-order modes is substantially minimized.

Abstract: A wavelength division multiplexing system has a wavelength division multiplexer and a wavelength division demultiplexer. The wavelength division demultiplexer is in series with the wavelength division multiplexer to process at least one optical signal to generate at least one processed optical signal. The wavelength division multiplexer and the wavelength division demultiplexer cooperate to introduce substantially zero total chromatic dispersion in the processed optical signal. In one version, the wavelength division multiplexer and the wavelength division demultiplexer introduce opposing functions of chromatic dispersion into the at least one processed optical signal.

Abstract: A variable optical power limiter is disclosed. An apparatus according to aspects of the present invention includes an optical waveguide disposed in semiconductor material. An optical beam is to be directed through the optical waveguide. The optical beam is to generate free carriers in the optical waveguide via two-photon absorption in response to an input power level of the optical beam. A diode structure is disposed in the optical waveguide. The diode structure is coupled to be biased to control free carrier lifetimes of the free carriers in the optical waveguide to set an output power of the optical beam to a clamped output power level in response to the bias of the diode structure.

Abstract: An optical modulator structure includes at least two waveguide structures for inputting and outputting an optical signal. At least one ring resonator structure provides coupling between the at least two waveguide structures. The at least one ring resonator structure includes Ge or SiGe.

Abstract: A method of and apparatus for modulating an optical carrier by an incident electromagnetic field. The electromagnetic field propagates in a dielectric-filled transverse electromagnetic waveguide, At least one slice of an electro-optic material is disposed in the dielectric-filled transverse electromagnetic waveguide, the electro-optic material in the dielectric-filled transverse electromagnetic waveguide having at least one optical waveguide therein which has at least a major portion thereof guiding light in a direction orthogonal with respect to a direction in which the dielectric-filled transverse electromagnetic waveguide guides the incident electromagnetic field. Light is caused to propagate in the at least one optical waveguide in the at least one slice of an electro-optic material in the dielectric-filled transverse electromagnetic waveguide for modulation by the incident electromagnetic field.

Abstract: An optical pulse position modulator includes a substrate with parallel first and second sides, the substrate including a first waveguide channel and a parallel second waveguide channel orthogonal to the first and second sides, a linear chirped grating orthogonal to and upon the first and second waveguide channels, and at least a first electrode along the first waveguide channel to apply a voltage modulation thereto. A first optical circulator has a first port coupled to a pulsed optical carrier signal, and a second port coupled to the first waveguide channel on the first side of the substrate, and a second optical circulator has a fourth port coupled to the third port of the first optical circulator, and a fifth port coupled to the second waveguide channel on the second side of the substrate. An output of the second waveguide channel is a position modulated optical pulse signal.

Abstract: Embodiments of the inventions described herein comprise a device and method for manipulating an optical beam. The method comprises propagating an optical beam through a waveguide in proximity to a resonant cavity and pumping the resonant cavity with sufficient optical power to induce non-linearities in the refractive index of the resonant cavity. The method further comprises tuning the resonant frequency band of the resonant cavity with a modulation signal such that the optical beam is manipulated in a useful way.

Abstract: An apparatus and a method by which polarization components may be processed separately, for example, to enable a polarization beam splitter (PBS) or a switch. In one embodiment, the apparatus includes: first and second Mach-Zehnder interferometers, each Mach-Zehnder interferometer having input and output optical couplers and two internal optical arms, each optical arm connecting one output of the input optical coupler to a corresponding input of the output optical coupler, the output optical coupler of the first Mach-Zehnder interferometer being the input optical coupler of the second Mach-Zehnder interferometer, wherein the input optical coupler of the first Mach-Zehnder interferometer is configured to transmit one polarization component of the light to two of the outputs thereof and to transmit a different polarization of the light to substantially only one of the outputs thereof in response to receiving said light at an input thereof.

Abstract: It is an object of the invention to provide an optical modulator in which a connection substrate or a terminal substrate is disposed outside an optical modulation element and which can maintain at a proper voltage amplitude value a modulation signal applied to an optical modulation element. An optical modulator includes: a substrate having electro-optic effect; an optical waveguide formed on the substrate; an optical modulation element 1 having a modulation electrode (which includes a signal electrode 2) for modulating light passing through the optical waveguide; and a connection substrate 20 disposed outside the substrate to supply a modulation signal for driving the optical modulation element to the optical modulation element.

Abstract: A method, apparatus, and computer program product are provided for optimizing the pulse shape of optical signals output from an optical transmitter. The optical transmitter includes an optical modulator controlled by a bias voltage and a signal drive level, wherein the bias voltage and signal drive level are controlled automatically in a systematic way in dependence on one another to adapt the pulse shape of an optical output signal for optimal transmission over a transmission line.

Abstract: A vital sign measurement device includes a sensor fixation device, a sensor frame held by the sensor fixation device, an optical sensing system 104 held by the sensor frame, and an output unit. The sensor fixation device is adapted to be placed against an anatomical location of a subject, within which is an artery. The optical sensing system 104 includes an optical waveguide, an optical source device to supply optical energy to the optical waveguide, and an optical detector to detect an amount of optical energy exiting the optical waveguide. The optical sensing system 104 is adapted to sense an arterial pulse from the compression or flexing of at least a portion of the optical waveguide resulting in reduction of the amount of light exiting the optical waveguide. The output unit is configured to receive a signal indicative of the amount of light exiting the optical waveguide and to generate a measure of the vital sign based at least in part on the received signal.

Abstract: A silicon electro-optic waveguide modulator is formed using a metal-oxide-semiconductor (MOS) configuration. Various embodiments are described using different modes of operation of the MOS diode and gate oxide thicknesses. In one example, a high-speed submicron waveguide active device is formed using silicon-on-insulator. A micro-ring resonator intensity-modulator exhibits switching times on the order of tens of pS with modulation depth of 73% with a bias voltage of 5 volts.

Abstract: Techniques are generally disclosed for optical devices that may be used to implement a variety of logic devices or other circuits by optical means. Example optical devices use a photodiode to alter the charge carrier concentration in a waveguide, thereby altering the index of refraction of the waveguide. The photodiode may be driven by an optical signal, which may be coupled to the photodiode through an optical waveguide. The optical signal may be configured to control the phase of coherent light coupled through the waveguide. A variety of logic devices and other circuits may be implemented by allowing the light coupled through the waveguide to constructively or destructively interfere with other coherent light.

Abstract: The present invention provides methods to control phase shift of delay demodulation devices to reduce Polarization Dependent wavelength (PD?) to be less than, for example, 0.5 GHz (i.e. 0.004 nm).

Abstract: An object of the present invention is, in an optical modulator, to increase the production yield by enhancing the patterning accuracy of the electrodes, as well as to reduce the electrode loss by increasing the thickness of the electrodes. An optical modulator has a substrate 5 made of an electro-optical material; a modulation electrode 2A, 3A, 2B provided on the substrate 5; and an optical waveguide 1c provided on the substrate 5. Light propagating through the optical waveguide 1c is modulated by applying a modulation voltage to the modulation electrode. At least a part of the modulation electrode includes a base 2a, 3a formed on the substrate 5 and a projection part 2b, 3b having a width narrower than that of the base.

Abstract: A signal interface includes a dual-drive device having a first and a second input port that receive an outgoing signal. One of the first and the second input ports also receive an incoming signal. The dual-drive device passes the incoming signal to an output port while isolating the outgoing signal from the incoming signal.

Abstract: Embodiments of an optical device, an array of optical devices, and a technique for fabricating the optical device or the array are described. This optical device is implemented on a substrate (such as silicon), and includes a thermally tunable optical waveguide that has good thermal isolation from its surroundings. In particular, a portion of a semiconductor in the optical device, which includes the optical waveguide, is free standing above a gap between the semiconductor layer and the substrate. By reducing the thermal coupling between the optical waveguide and the external environment, the optical device can be thermally tuned with significantly less power consumption.

Abstract: Embodiments of an optical device, an array of optical devices, and a technique for fabricating the optical device or the array are described. This optical device is implemented using two semiconductor layers (such as silicon), one of which includes a heater and the other includes a thermally tunable optical waveguide. Spatially separating these two functions in the optical device results in more efficient heat transfer between the heater and the optical waveguide, reduced heat transfer to the surroundings, and reduced optical losses in the optical waveguide relative to existing silicon-based optical devices.

Abstract: An optical system having at least two waveguides that are deformable to provide adjustments to dispersion and path length.

Abstract: An AC-coupled differential drive circuit for an optical modulator is utilized, where a common “node” is defined between top (or bottom) plates of the modulator arms themselves (the “arms” of a modulator taking the form of MOS capacitors). A low pass filter is disposed between the differential driver output and the modulator's common node to provide the desired AC coupling by filtering out the DC bias voltage of the driver circuit itself without the need for a separate, external AC coupling capacitor. An independent, adjustable DC potential can then be applied to the common node, and will appear in a balanced manner across each arm of the modulator to provide the desired DC bias for the modulator independent of the DC bias of the driver circuit.

Abstract: The present invention relates to a semiconductor optoelectronic waveguide having a nin-type hetero structure which is able to stably operate an optical modulator. On the upper and lower surfaces of the core layer determined for the structure so that electro-optical effects are effectively exerted at an operating light wavelength and are provided with intermediate clad layers having a band gap which is greater than that of the core layer 11. Respectively on the upper and the lower surface of the intermediate clad layer are provided the clad layers having the band gap which is greater than those of the intermediate clad layers. On the upper surface of the clad layer are sequentially laminated a p-type layer and an n-type layer. In the applied voltage range used under an operating state, a whole region of the p-type layer and a part or a whole region of the n-type layer are depleted.

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: The optical modulator comprises an optical branching unit branching incident light into a first signal light and a second signal light; a first Mach-Zehnder modulator modulating the first signal light; a second Mach-Zehnder modulator modulating the second signal light; a phase shifter giving a fixed phase shift to the phase of the output light from the second Mach-Zehnder modulator; and an optical multiplexer multiplexing the output light from the first Mach-Zehnder modulator and the output light from the phase shifter. The phase shifter gives the phase shift so that the two input lights to the optical multiplexer have a phase difference of 60 degrees, and the first and second Mach-Zehnder modulators are driven by three-level signals.

Abstract: The invention relates to a method and to an apparatus for compensating the polarization-dependent shift of the center frequency in an optical filter comprising an interferometer by way of compensating the birefringence in at least one waveguide of the interferometer, wherein at least one half-wave plate is arranged into the optical path of the interferometer and at least a section of the waveguide (16, 17) on the right and on the left of the half-wave plate (11) is brought to a pre-selectable temperature, and wherein at least one section on the right of the half-wave plate (11) is brought to a first temperature T1, and at least one section on the left of the half-wave plate (11) is brought to a second temperature T2.

Abstract: A communications cable includes two or more optical fibers embedded in a jacket which supports the fibers at a predetermined center-to-center distance. The jacket including at least one reference surface oriented at a predetermined angle to the reference plane. The communications cable may also include one or more electrical conductor. Apparatus is provided for preparing the ends of the optical fibers without use of a ferrule, and for transmitting multiple electrical and/or optical signals over the communications cable.

Abstract: A hitless tunable filter may include a ring resonator, a Mach-Zehnder coupler, and first and second phase shifters. The Mach-Zehnder coupler may include a switching arm that is coupled to the ring resonator at first and second coupling points. The first phase shifter may be used to introduce a first phase shift to light propagating through the ring resonator, while the second phase shifter may be used to introduce a second phase shift to light propagating through the Mach-Zehnder coupler. The Mach-Zehnder coupler may have a free spectral range substantially equal to a free spectral range of the ring resonator divided by a non-negative integer.

Abstract: Light having components of frequencies f0, f+1 and f?1 outputted from an optical modulator (10) is monitored, a second light detection means (14b) measures the power P2 of all the components, and a first light detection means (14a) measures the power P1 with frequency f0 component cut out by a filter means (13). Based on these light receiving powers (P1) and (P2), phase differences imparted by the respective DC electrodes of Mach-Zehnder optical waveguides (MZ-A, MZ-B, MZ-C) of the optical modulator (10) are controlled. The control is performed to minimize the light receiving power (P1) and to maximize the light receiving power (P2).

Abstract: An optical functional waveguide having a small size, used with stored energy, controlling the phase of light at high speed, and adjusting the optical path length. The optical functional waveguide includes a substrate (11), a quartz waveguide clad (12), a quartz waveguide core (13), groove structures (14), a filling material (15), and heater electrode (16). The filling material (15) placed in the groove structures (14) is, e.g., a resin transparent to the wavelength region of the guided light, and the refractive index temperature coefficient is about 10 to 100 times that of quartz. The heater electrode (16) is interposed between the groove structures (14) provided along the optical path. Therefore, the temperature of the filling material (15) can be varied sharply and quickly with little energy expended.

Abstract: An apparatus for generating a frequency-variable signal includes a light source; first and second resonators, to which the optical signals from the light source are input; a structure optically connected to the first resonator so as to be deformable by strain; a first and a second optical fiber gratings located on the structure to filter optical signals of a first wavelength and a second wavelength, respectively; and a photoelectric converter optically connected to the first resonator to generate a signal of a frequency corresponding to an interval between the first wavelength and the second wavelength. The interval between the first wavelength and the second wavelength corresponds to a degree of deformation of the structure.

Abstract: An optical modulator is provided which includes: an optical splitting part that splits an input light wave into two light waves; two optical waveguides that propagate the two light waves into which the input light wave is split, respectively; a first SSB modulating part that is provided in one of the two optical waveguides and modulates a light wave, which propagates into the first SSB modulating part, with a carrier frequency so that the light wave is converted into a different light wave having a single side band; a second SSB modulating part that is provided in the other of the two optical waveguides and modulates a light wave, which propagates into the second SSB modulating part, with a data signal in order to generate a signal light wave having a different single side band; and an optical combining part that combines the light wave modulated by the first SSB modulating part with the signal light wave generated by the second SSB modulating part.

Abstract: A silicon electro-optic waveguide modulator is formed using a metal-oxide-semiconductor (MOS) configuration. Various embodiments are described using different modes of operation of the MOS diode and gate oxide thicknesses. In one example, a high-speed submicron waveguide active device is formed using silicon-on-insulator. A micro-ring resonator intensity-modulator exhibits switching times on the order of tens of pS with modulation depth of 73% with a bias voltage of 5 volts.

Abstract: Embodiments of MEMS devices include a movable layer supported by overlying support structures, and may also include underlying support structures. In one embodiment, the residual stresses within the overlying support structures and the movable layer are substantially equal. In another embodiment, the residual stresses within the overlying support structures and the underlying support structures are substantially equal. In certain embodiments, substantially equal residual stresses are be obtained through the use of layers made from the same materials having the same thicknesses. In further embodiments, substantially equal residual stresses are obtained through the use of support structures and/or movable layers which are mirror images of one another.

Abstract: A bidirectional optical module having a device 1 for emitting transmitting signal light, an optical fiber 8 which the transmitting signal light from the device enters, a light-receiving device 9 which light from the optical fiber enters, and a wavelength splitting filter 4. The transmitting signal light emitted from the device is sent forward through the optical fiber, and the receiving signal light is received through the optical fiber. The bidirectional optical module has an optical device (optical isolator) of a reflection polarizer 6 bonded to an end face of the optical fiber, a Faraday rotator 5 disposed integrally on the reflection polarizer and an absorption polarizer 3 disposed on an optical path extending between the device and the filter. The reflection polarizer has a wavelength dependency which functions as a polarizer for the transmitting signal light, but does not function as a polarizer for the receiving signal light.

Abstract: An optical fiber is provided, which is unlikely to cause interlayer delamination between a glass optical fiber and a primary coating layer even when it is immersed in water. The optical fiber of the present invention includes a glass optical fiber 1 consisting of a core and a cladding, a primary coating layer 2 overlaid on the glass optical fiber, and a secondary coating layer 3 overlaid on the primary coating layer, wherein the relaxation modulus of the secondary coating layer is set at 400 MPa or less.

Abstract: A light source apparatus with modulation function has a wavelength conversion module (75) composed of a nonlinear optical material with a structure having a nonlinear constant modulated periodically. It outputs a difference frequency or sum frequency produced by multiplexing pumping light from semiconductor laser light sources (71) and (72) with different wavelengths through a WDM coupler (74) and by launching the multiplexed light into the optical waveguide. The semiconductor laser light source (72) includes a diffraction grating. The semiconductor laser light source (71) includes a section for modulating output light emitted from its semiconductor laser, and is connected to an external FBG (73) which has a reflection band narrower than a resonance wavelength spacing determined by the device length of the semiconductor laser. The FBG (73) is supplied with the modulated output.

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.