Abstract: A Mach-Zehnder optical modulator includes a join-and-branch portion, two light wave guides connected with the join-and-branch portion, two output light waveguides connected with the join-and-branch portion, arm electrodes respectively provided on the two light waveguides, light intensity detection electrodes respectively provided on the two output light waveguides, and a leakage suppression electrode provided between the arm electrodes and the light intensity detection electrodes.

Abstract: A mach-zehnder optical modulator includes a substrate having electrooptical effect, wherein: the substrate has an inputting waveguide portion, two intermediate waveguide portions, an outputting waveguide portion and a sub optical waveguide portion, the inputting waveguide portion being branched and coupled to the two intermediate waveguide portions, the two intermediate waveguide portions being combined and coupled to the outputting waveguide portion, the sub optical waveguide being provided on at least one side of the outputting optical waveguide portion and having a given distance from the outputting optical waveguide portion, the sub optical waveguide portion guiding an off-light emitted from a combining portion of the two intermediate waveguide portions; and a width of a starting point of the sub optical waveguide portion is larger than the outputting waveguide portion.

Abstract: Various exemplary embodiments relate to an optical isolator in an integrated optical circuit including: a first optical modulator configured to provide a first periodic phase modulation on an input optical signal; a second optical modulator configured to provide a second periodic phase modulation on the modulated optical signal; and an optical waveguide having a length L connecting the first optical modulator to the second optical modulator; wherein the phase difference between the first and second periodic phase modulation is ?/2, and wherein the length L of the optical waveguide causes a phase delay of ?/2 on an optical signal traversing the optical waveguide.

Abstract: A solid state light source comprising a light pump outputting light energy; a waveguide optically coupled to the light pump source for receiving the light energy; and a down-converter for converting the light energy from the waveguide to a lesser light energy.

Abstract: A disclosed remote work system includes a light source and a nonlinear converter optically coupled to and remote from the light source. The nonlinear light converter converts a narrowband light pulse received from the light source to a converted spectrum light pulse. The system also includes a work element coupled to the nonlinear light converter. The work element performs a work operation using the converted spectrum light pulse. A related remote work method includes generating a narrowband light pulse and conveying the narrowband light pulse to a remote location. The method also includes converting the narrowband light pulse to a converted spectrum light pulse at the remote location. The method also includes performing a sense operation or work operation at the remote location using the converted spectrum light pulse.

Abstract: An optical modulator includes: a substrate made of a material having an electro-optical effect; an optical waveguide formed on the substrate; and a modulation electrode for modulating an optical wave propagating through the optical waveguide, wherein emitted light emitted from the optical waveguide is guided by optical fiber, and polarization of the substrate is reversed in a predetermined pattern along the optical waveguide so as to provide waveform distortion having a characteristic opposite to a wavelength dispersion characteristic of the optical fiber.

Abstract: One aspect of the invention relates to a photonic device having a wavelength-dependent transmission or filter characteristic, comprising: a Splitter Polarization Rotator receiving polarized light and providing a first resp. second wave; a first resp. second waveguide arm connected to the SPR for propagating a first resp. second polarization mode (TM, TE) of the first resp. second wave, the second polarization mode being different from the first polarization mode; and a Polarization Rotator and Combiner for combining the propagated first resp. second waves; wherein the dimensions of the first and second arm are selected to cancel the influence of an external effect on the wavelength-dependent characteristic. Another aspect of the invention relates to a method for reducing the sensitivity of said integrated photonic device, comprising splitting a polarized light beam, propagating light waves of different polarity through two waveguide arms of specific dimensions, and recombining them.

Abstract: An optical system may include: a polarization beam splitter having: a first end having an input configured to receive multiple optical signals; a second end having a first output and a second output, where the first output may provide first components, having a first polarization of the multiple optical signals, and the second output may provide second components, having a second polarization, of the multiple optical signals; and a first waveguide having a first width and a second waveguide having a second width, where the first waveguide and the second waveguide may each have a length corresponding to a difference between the first width and the second width, where the first waveguide and the second waveguide may be configured to induce a phase shift of the plurality of optical signals based on the first width, the second width, and the length of the first waveguide and the second waveguide.

Abstract: This disclosure is directed to fiber-optic modulators that can be integrated in optical fibers to encode data in optical signals. In one aspect, a fiber-optic modulator includes a weak planar, sub-wavelength grating disposed between an end of a first optical fiber and an end of a second optical fiber. A first electrode is disposed on an edge of the grating and connected to an electronic signal source, and a second electrode is disposed on the edge of the grating opposite the first electrode and connected to the electronic signal source. The grating includes a grating pattern to reflect a channel input to the first optical fiber when a low or no current portion of an electronic signal to be generated by the electronic signal source is applied to the grating and to transmit the channel when a high current portion of the electronic signal is applied to the grating.

Abstract: A configuration for routing electrical signals between a conventional electronic integrated circuit (IC) and an opto-electronic subassembly is formed as an array of signal paths carrying oppositely-signed signals on adjacent paths to lower the inductance associated with the connection between the IC and the opto-electronic subassembly. The array of signal paths can take the form of an array of wirebonds between the IC and the subassembly, an array of conductive traces formed on the opto-electronic subassembly, or both.

Abstract: A polarization control device includes a MMI device having primary-side and secondary-side end-faces; a first phase shifter optically coupled to a first port in the primary-side end-face; a first optical waveguide optically coupled via the first phase shifter to the first port in the primary-side end-face; a second optical waveguide optically coupled to a second port in the primary-side end-face; and a tapered waveguide optically coupled to a first port in the secondary-side end-face. The first and second ports in the primary-side end-face are located on first and second axes, respectively. The first port in the secondary-side end-face is located on a third axis located between the first and second axes. The first, second, and third axes extend in a direction from the primary-side end-face to the secondary-side end-face. The tapered waveguide has a width decreasing in a direction from one end to the other end of the tapered waveguide.

Abstract: A DP QPSK optical modulator includes an input port; an optical branching unit; an optical modulation unit having first through fourth Mach-Zehnder interferometers; a first phase-change unit connected to the third Mach-Zehnder interferometer; a second phase-change unit connected to the fourth Mach-Zehnder interferometer; an optical multiplexer; and a multimode interference coupler including a multimode interference waveguide, first through third input ports, and an output port having a taper-shaped waveguide. The first Mach-Zehnder interferometer is connected to the first input port. One end of the optical multiplexer is connected to the second Mach-Zehnder interferometer and the third Mach-Zehnder interferometer via the first phase change unit. The other end of the optical multiplexer is connected to the second input port. The fourth Mach-Zehnder interferometer is connected to the third input port via the second phase-change unit.

Abstract: A method and apparatus for providing optical supercontinuum. The method comprises creating a spectrally narrow phase feature within a supercontinuum spectrum produced from a laser pulse that has been subjected to supercontinuum generation, thereby producing a modified supercontinuum spectrum, and propagating the modified supercontinuum spectrum through an optical waveguide that is suitable for supercontinuum generation, thereby further modifying the modified supercontinuum spectrum. The method may include modifying the modified supercontinuum spectrum by increasing its energy in a vicinity of the phase feature.

Abstract: An optical modulation apparatus includes: a substrate; a first optical waveguide and a second optical waveguide formed at an interval on the substrate; an electrode provided along at least one of the first optical waveguide and the second optical waveguide; and a power source coupled to the electrode to apply a voltage to at least one of the first optical waveguide and the second optical waveguide, wherein at least one of the first optical waveguide and the second optical waveguide includes a diffraction grating region where light having a wavelength ? is reflected, and a phase shift region where a phase of the light is shifted by an amount in a range of 0 to ?/2.

Abstract: A system includes a waveguide that guides a beam of radiation, a variable delay unit, and a polarization-dependent modulating unit. The variable delay unit modulates the refractive index in a region, and the waveguide makes a plurality of passes through the region. The polarization-dependent element compensates for birefringence associated with the beam of radiation and includes a polarization splitter and a plurality of modulating elements. The polarization splitter has a first arm and a second arm that each include modulation segments. The beam of radiation is split between the first arm and the second arm and recombined after traversing the modulation segments. The recombination of the beam generates a first polarized beam of radiation and a second polarized beam of radiation. The plurality of modulating elements apply a first and second modulation to the first polarized beam of radiation and the second polarized beam of radiation respectively.

Abstract: Disclosed is an optical modulator module including an optical modulator configured to have a signal electrode and a ground electrode; a conductive package configured to accommodate the optical modulator and have electrical continuity with the ground electrode of the optical modulator; a substrate configured to have a ground electrode on a first surface thereof electrically connected to the package by solder or a conductive adhesive and have a signal electrode on another surface thereof; and a lead pin configured to electrically connect the signal electrode of the optical modulator to the signal electrode of the substrate.

Abstract: Systems and methods are provided for modulating, channels in dense wavelength division multiplexing (“DWDM”) systems. In one aspect, a modulation and wavelength division multiplexing system includes a channel source and a waveguide tree structure disposed on a substrate. The tree structure includes waveguides branching from a root waveguide. The waveguides include two or more terminus waveguides coupled to the channel source. The system also includes one or more modulator arrays disposed on the substrate. Each modulator array is optically coupled to one of the two or more terminus waveguides and is configured to modulate channels injected into a terminus waveguide from the channel source to produce corresponding optical signals that propagate from the terminus waveguide along one or more of the waveguides to the root waveguide.

Abstract: An optical pulse delay generator is provided. The optical pulse delay generator includes a first optical converter which is dispersive and separates the spectral components of the incoming optical pulse in a time domain. The first optical converter generating a converted optical signal. The optical pulse delay generator also includes a modulator to modulate the converted optical signal and to generate a modulated optical signal and a second optical converter connected to the modulator. The second optical converter being dispersive for overlaying the previously separated spectral components in the time domain and generating the delayed optical output pulse. The dispersion imposed by the second optical converter has the same amount of dispersion, but the opposite sign, as the first optical converter. At least one of the first and second optical converter includes at least two waveguide resonator rings which differ in their optical length.

Abstract: Some embodiments of the disclosed subject matter provide systems, devices, and methods for tuning resonant wavelengths of an optical resonator. Some embodiments of the disclosed subject matter provide systems, devices, and methods for tuning dispersion properties of photonic crystal waveguides. In some embodiments, methods for tuning a resonant wavelength of an optical resonator are provided, the methods including: providing an optical resonator having a surface; determining an initial resonant wavelength emitted by the optical resonator in response to an electromagnetic radiation input; determining a number of layers of dielectric material based on a difference between the initial resonant wavelength and a target resonant wavelength and a predetermined tuning characteristic; and applying the determined number of layers of dielectric material to the surface of the optical resonator to tune the initial resonant wavelength to a tuned resonant wavelength.

Abstract: An apparatus comprising a Mache-Zehnder interferometer. The Mache-Zehnder interferometer comprises: a 1×2 optical splitter having an optical input, a 2×2 optical coupler having first and second optical outputs, two optical waveguide arms end-connecting each optical output of the 1×2 optical splitter to a corresponding optical input of the 2×2 optical coupler, a variable optical phase shifter on one of the waveguide arms and a plurality of optical resonators, each optical resonator being controllably coupled along one of the optical waveguide arms. An optical path length between the optical input of the 1×2 optical coupler and the first optical output of the 2×2 optical coupler is substantially the same via the first optical waveguide arm and the second optical waveguide arm when the optical resonators are decoupled from the optical waveguide arms.

Abstract: In an optical signal processing apparatus, carrier light propagates through a nonlinear optical medium. An optical combiner optically combines output control light for generating idler light of the carrier light with the carrier light. An optical splitter splits the idler light from the carrier light. A receiver acquires a signal multiplexed on the carrier light from the idler light split by the optical splitter.

Abstract: An optical-switch driver circuit includes a pulse signal source and a voltage-applying circuit. The pulse signal source generates pulse waves that rise from a first voltage to a second voltage. The voltage-applying circuit, for one of the pulse waves, outputs a voltage higher than the third voltage, then outputs a voltage lower than the third voltage, and further outputs the third voltage.

Abstract: When phases of lights passing through arms are adjusted, a first DC bias and a first modulation signal are applied to one arm from one modulating electrode, and a second DC bias and a second modulation signal are applied to the other arm from the other modulating electrode. The first and second DC biases are applied to the modulating electrodes such that a rate of a product of a length of one modulating electrode and the first DC bias and a product of a length of the other modulating electrode and the second DC bias is kept at a constant value. According to this constitution, it is possible to enable an optimum control of a phase difference between the arms and a precise control of wavelength chirp characteristics with a simple element constitution, and an optical modulation of which device size is small and having fine characteristics is enabled.

Abstract: Provided is an integrated optical current sensor for measuring the magnitude of current. The integrated optical current sensor is fabricated by integrating optical elements, such as a thermo-optic phase modulator, a waveguide polarizer and an optical coupler, on a single substrate. As compared to the known current sensors using optical fibers, the integrated optical current sensor is more compact and enables measurement of current with higher reliability. Provided also is a method for producing current sensor chips in a large scale by using a process for fabricating integrated optical elements.

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: A high power fiber laser is configured with a multimode active fiber and input and output single mode passive fibers butt-spliced to respective opposite ends of the active fiber. If the input passive and active fibers do not have substantially matched diameters, a SM radiation coupled into the active fiber may excite fundamental and high order modes which, while interfering with one another, create a non-uniform distribution of refractive index in each of forward and backward light propagation directions along the resonator of the laser. The variable longitudinal perturbation components of the refractive index in respective forward and backward directions along an optical path in the active fiber are distributed in accordance with respective cosine functions.

Abstract: An apparatus and method for analysing a sample. The apparatus comprises a waveguide (205), including an input for receiving light and an output, a first microring resonator (210) optically coupled to the waveguide (205), and a first flexible optical waveguide (215) optically coupled to the first microring resonator (210). The first flexible optical waveguide (215) includes a portion for interacting with the sample. Light transmitted from the output of said waveguide (205) is modulated at a first optical resonant wavelength of the first microring resonator (210) and the modulation is a function of a distance between the first flexible optical waveguide (215) and the first microring resonator (210).

Abstract: The present invention provides an optical 90-degree hybrid circuit for reducing wavelength dependency of an IQ phase difference. An optical 90-degree hybrid circuit according to the present invention comprises a first demultiplexing optical coupler including a first and second input port, a second demultiplexing optical coupler including a third and fourth input port, first and second arm waveguides connected to the first and second input port, each having the same length, a third and fourth arm waveguides connected to the third and fourth input port, each having the same length, a 90-degree phase shift section installed in one of the first to fourth arm waveguides, a first optical coupler connected to the first and third arm waveguide, and a second optical coupler connected to the second and fourth arm waveguide, the light is inputted into the first and fourth input port or into the second and third input port.

Abstract: Optical couplers for injecting an optical control signal onto an optical fiber include a micro-ring resonator that is coupled to the optical fiber, an optical transmission path and a modulator that is configured to vary a distance between the optical transmission path and the micro-ring resonator in order to selectively couple light from the optical transmission path onto the micro-ring resonator.

Abstract: The present invention relates to devices which operate on gradient optical forces, in particular, nanoscale mechanical devices which are actuable by gradient optical forces. Such a device comprises a waveguide and a dielectric body, with at least a portion of the waveguide separated from the dielectric body at a distance which permits evanescent coupling of an optical mode within the waveguide to the dielectric body. This results in an optical force which acts on the waveguide and which can be exploited in a variety of devices on a nano scale, including all-optical switches, photonic transistors, tuneable couplers, optical attenuators and tuneable phase shifters. The waveguide can also comprise a gap such that two cantilever bridges are formed.

Abstract: An optical structure can include a nanocrystal on a surface of an optical waveguide in a manner to couple the nanocrystal to the optical field of light propagating through the optical waveguide to generate an emission from the nanocrystal.

Abstract: A system, e.g. an optical modulator, includes an optical waveguide and a plurality of optical resonators. The optical waveguide is located along a surface of a planar substrate. The plurality of optical resonators is also located along the surface and coupled to the optical waveguide. Each of said optical resonators is configured to resonantly couple to the optical waveguide at a different optical frequency.

Abstract: A system for integrated power combiners is disclosed and may include receiving optical signals in input optical waveguides and phase-modulating the signals to configure a phase offset between signals received at a first optical coupler, where the first optical coupler may generate output signals having substantially equal optical powers. Output signals of the first optical coupler may be phase-modulated to configure a phase offset between signals received at a second optical coupler, which may generate an output signal having an optical power of essentially zero and a second output signal having a maximized optical power. Optical signals received by the input optical waveguides may be generated utilizing a polarization-splitting grating coupler to enable polarization-insensitive combining of optical signals. Optical power may be monitored using optical detectors. The monitoring of optical power may be used to determine a desired phase offset between the signals received at the first optical coupler.

Abstract: A semiconductor-based optical modulator is presented that includes a separate phase control section to adjust the amount of chirp present in the modulated output signal. At least one section is added to the modulator configuration and driven to create a pure “phase” signal that will is added to the output signal and modify the ei? term inherent in the modulation function. The phase modulation control section may be located within the modulator itself, or may be disposed “outside” of the modulator on either the input waveguiding section or the output waveguiding section. The phase control section may be formed to comprise multiple segments (of different lengths), with the overall phase added to the propagating signal controlled by selecting the different segments to be energized to impart a phase delay to a signal propagating through the energized section(s).

Abstract: An optical modulation apparatus, including: a Mach-Zehnder optical modulator having two light waveguides, two output light waveguides, and a join-and-branch portion located therebetween; a drive circuit configured to output a modulation signal to modulation electrodes provided respectively on the two light waveguides as a differential signal, the modulation signal modulating lights propagated in the two light waveguides; a phase adjustment circuit configured to control first phase control signals to be output to phase adjustment electrodes provided respectively on the two light waveguides, and adjust phases of lights propagated in the two light waveguides; a phase shift control circuit configured to switch second phase control signals to be output to phase shift electrodes provided respectively on the two light waveguides, and change phases of the lights propagated in the two light waveguides; and a signal polarity reversal circuit configured to reverse a polarity of the differential signal.

Abstract: In a light control element comprising a thin plate having a thickness of 10 [mu]m or less and exhibiting electro optic effect, an optical waveguide formed on the thin plate, and a control electrode for controlling light passing through the optical waveguide, the control electrode includes a first electrode and a second electrode so arranged as to sandwich the thin plate, and the first electrode has a coplanar electrode consisting of a first signal electrode and a ground electrode, while the second electrode has a second signal electrode. Modulation signals having mutually inverted amplitudes are inputted to the first signal electrode of the first electrode and the second signal electrode of the second electrode such that the modulation signals cooperate to apply an electric field to the optical waveguide.

Abstract: A nano-optomechanical transducer provides ultrabroadband coherent optomechanical transduction based on Mach-wave emission that uses enhanced photon-phonon coupling efficiencies by low impedance effective phononic medium, both electrostriction and radiation pressure to boost and tailor optomechanical forces, and highly dispersive electromagnetic modes that amplify both electrostriction and radiation pressure. The optomechanical transducer provides a large operating bandwidth and high efficiency while simultaneously having a small size and minimal power consumption, enabling a host of transformative phonon and signal processing capabilities. These capabilities include optomechanical transduction via pulsed phonon emission and up-conversion, broadband stimulated phonon emission and amplification, picosecond pulsed phonon lasers, broadband phononic modulators, and ultrahigh bandwidth true time delay and signal processing technologies.

Abstract: The invention provides a semiconductor optical modulator including a two-step mesa optical waveguide having a first clad layer (101); a mesa-like core layer (102) formed over the first clad layer (101); and a second clad layer (103) formed into a mesa shape over the core layer (102), and having a mesa width smaller than that of the core layer (102). The two-step mesa optical waveguide includes a multi-mode optical waveguide region to which an electric field is applied or into which an electric current is injected, and a single-mode optical waveguide region to which the electric field is not applied and into which the electric current is not injected. When the mesa width of the core layer in the multi-mode optical waveguide region is defined as Wmesa1, and the mesa width of the core layer in the single-mode optical waveguide region is defined as Wmesa2, Wmesa1>Wmesa2 is satisfied.

Abstract: An optoelectronic swept-frequency semiconductor laser coupled to a microfabricated optical biomolecular sensor with integrated resonator and waveguide and methods related thereto are described. Biomolecular sensors with optical resonator microfabricated with integrated waveguide operation can be in a microfluidic flow cell.

Abstract: A Mach-Zehnder wavelength division multiplexer (WDM) is provided. The WDM has a short length with flat passband and low crosstalk. Since passband is flattened, crosstalk is reduced and length of the WDM is shortened, the WDN can be used for optical communication and optical interconnection in a single chip.

Abstract: An apparatus, comprising a substrate with a planar surface an optical power splitter on the surface, and an optical power combiner on the surface. The apparatus also comprises pairs of optical waveguides located on the planar surface, each waveguide of the pairs connecting a corresponding output of the optical power splitter to a corresponding input of the optical power combiner. The apparatus also comprises a plurality of optical resonators located on the surface, each of the resonators of the plurality being evanescently coupled to a corresponding one of the waveguides. For each particular one of the pairs, resonant frequencies of the optical resonators coupled to the waveguides of the particular one of the pairs are about the same. Resonant frequencies of each pair of the optical resonators coupled to two of the waveguides in different ones of the pairs are different.

Abstract: An optical XOR gate is formed as a photonic integrated circuit (PIC) from two sets of optical waveguide devices on a substrate, with each set of the optical waveguide devices including an electroabsorption modulator electrically connected in series with a waveguide photodetector. The optical XOR gate utilizes two digital optical inputs to generate an XOR function digital optical output. The optical XOR gate can be formed from III-V compound semiconductor layers which are epitaxially deposited on a III-V compound semiconductor substrate, and operates at a wavelength in the range of 0.8-2.0 ?m.

Abstract: A waveguide device for frequency mixing or conversion through birefringent phase matching, having a horizontal waveguide suspended above a substrate. The waveguide is formed of a zinc blende type III-V semiconductor material with a high nonlinear susceptibility.

Abstract: An optical transmitter module includes a light source, a first optical circulation unit, a first optical reflector, and an output unit. The light source emits a first light signal with a first wavelength, and a second light signal with a second wavelength. The first optical circulation unit includes three optical couplers and three optical isolators, which are alternately connected to one another to form a loop. The first optical circulation unit includes a first port at a first optical coupler, a second port at a second optical coupler, and a third port at a third optical coupler. The first port is optically coupled to the light source. The first optical reflector is optically coupled to the second port. The first optical reflector reflects the first light signal back to the second port. The output unit is optically coupled to the third port to output the first light signal.

Abstract: The present invention realizes an enhancement of a fabrication yield and a reduction of a size regarding an optical modulator or an optical device including polarization beam combining means. An optical modulator of the present invention (1) includes: first and second optical modulators (LN optical modulators (101) to (104)) that are formed on a substrate; a polarization beam rotating unit (107) that rotates at least one polarization beam of modulated light beams modulated by the first and second optical modulators; and a polarization beam combining element (110) that is disposed outside the substrate and that combines the polarization beams of the modulated light of which the polarization beams are rotated by the polarization beam rotating unit (107).

Abstract: A digital data transmission device is provided comprising optical waveguide architecture, a sideband generator, a modulation controller, an optical filter, a data mapping unit, and a phase controller. The optical waveguide architecture is configured to direct an optical signal through the sideband generator and the optical filter. The sideband generator comprises an electrooptic interferometer comprising first and second waveguide arms. The modulation controller is configured to generate an electrical drive signal to drive the sideband generator at a control voltage that is substantially larger than V? to generate optical frequency sidebands about a carrier frequency of the optical signal. The optical filter is configured to discriminate between the optical frequency sidebands and the optical carrier frequency such that optical sidebands of interest can be directed through the optical waveguide architecture as an optical millimeter wave signal.

Abstract: A multi-mode interference includes a core portion suitable, at any point, for propagating an optical signal having multiple spatial modes. The core portion includes a shifting section for shifting phases of the spatial modes of the optical signal.

Abstract: Systems and methods for modulating light with light in high index contrast waveguides clad with graphene. Graphene exhibits a large nonlinear electro-optic constant ?3. Waveguides fabricated on SOI wafers and clad with graphene are described. Systems and methods for modulating light with light are discussed. Optical logic gates are described. Waveguides having closed loop structures such as rings and ovals, Mach-Zehnder interferometer, grating, and Fabry-Perot configurations, are described. Optical signal processing methods, including optical modulation at Terahertz frequencies, are disclosed. Optical detectors are described. Microelectromechanical and nanoelectromechanical systems using graphene on silicon substrates are described.

Abstract: There are provided an unbalanced Mach-Zehnder interferometer and a modulator based thereupon. The interferometer comprises a loop comprising a plurality of cascaded segments of polarization-maintaining fibers, into which an input signal is split such that two light portions of the split signal propagate concurrently in mutually opposite directions along the loop; and a first optical arrangement between a first and a second segment of the loop for rearranging the axes of propagation of the two light portions such that, on at least a one segment, the two light portions propagate along mutually orthogonal polarization axes of the polarization-maintaining fiber. The light portions are then recombined to mutually interfere. Birefringence of the segment(s) where the light portions propagate on mutually orthogonal polarization axes then provides a differential path length of the interferometer. An unbalanced Mach-Zehnder modulator is obtained by inserting a phase modulator within the loop.

Abstract: An optical circulator includes a first optical isolator including a first port and a second port and a plurality of optical isolators coupled to the second port of the first optical isolator. Each of the plurality of optical isolators comprise a first port and a second port.