Abstract: A signal interface comprises a non-reciprocal device having a first port that accepts a first electrical signal and a second port that accepts a second electrical signal. The non-reciprocal device passes the second electrical signal through the first port without a phase shift and passes the first electrical signal through the second port with a 180 degrees phase shift. An optical modulator receives an optical signal at an optical input port, a second signal at a first and a second electrical input port, the first electrical signal at a third electrical input port, and the phase-shifted first electrical signal from the non-reciprocal device at a fourth electrical input port. The optical modulator transmits the second electrical signal to the first port of the non-reciprocal device without a phase shift and modulates the first electrical signal on the optical signal and providing the modulated optical signal at an optical output port of the optical modulator.

Abstract: A modulator includes an interferometer waveguide structure formed on an electro-optical substrate, preferably a Z-cut lithium niobate or a Z-cut lithium tantalate. The substrate includes a domain inversion between a region near the first arm and a region near the second arm of the interferometer waveguide structure. In one example, two coplanar strip electrode structures, each extending near at least a portion of the first arm and the second arm, respectively, are electrically coupled to each other.

Abstract: An optical resonant modulator includes an optical ring resonator and an optical loop that is coupled to the optical ring resonator by two couplers. The optical ring resonator can have a hybrid design in which the ring resonator is formed on an electro-optically passive material and the optical loop is formed on an electro-optically active material. An amplification section can be inserted between the electro-optically passive and the electro-optically active sections. In analog applications, an optical resonator includes a Mach Zehnder interferometer section having an input and an output, with a feedback path coupling the output to the input. Applications of the optical modulator of the invention, and a method for modulating an optical signal also are disclosed.

Abstract: An optical waveguide device including an electro-optical crystal substrate having a top surface and a bottom surface; an optical waveguide path formed within a surface of the electro-optical crystal substrate; at least one electrode positioned above the optical waveguide path for applying an electric field to the optical waveguide path; and a silicon titanium oxynitride layer and a connecting layer for interconnecting the silicon titanium oxynitride layer to another surface of the electro-optical crystal substrate that is opposite to the surface in which the optical waveguide path is formed.

Abstract: Featured is a high power, broadband superfluorescent source with very low relative intensity noise (RIN) including a seed source, a modulator operably coupled to the seed source and a polarization maintaining (PM) amplifier operably coupled to the modulator. The output of the seed source is processed in the modulator so the modulator outputs a polarized optical output to the PM amplifier. The PM amplifier amplifies the modulated, polarized optical output so as to provide an amplified polarized optical output therefrom. Also featured is a feedback circuit operably coupled to the PM amplifier to control the transmission of the modulator so as to minimize the amplitude fluctuations in the output signal. Such a source is advantageous in high precision fiber optical rotation sensors and multiplexed strain sensing arrays.

Abstract: An optical waveguide device including an electro-optical crystal substrate having a top surface and a bottom surface; an optical waveguide path formed within a surface of the electro-optical crystal substrate; at least one electrode positioned above the optical waveguide path for applying an electric field to the optical waveguide path; and a silicon titanium oxynitride layer and a connecting layer for interconnecting the silicon titanium oxynitride layer to another surface of the electro-optical crystal substrate that is opposite to the surface in which the optical waveguide path is formed.

Abstract: An optical waveguide device including an electro-optical crystal substrate having a top surface and a bottom surface; an optical waveguide path formed within a surface of the electro-optical crystal substrate; at least one electrode positioned above the optical waveguide path for applying an electric field to the optical waveguide path; and a silicon titanium oxynitride layer and a connecting layer for interconnecting the silicon titanium oxynitride layer to another surface of the electro-optical crystal substrate that is opposite to the surface in which the optical waveguide path is formed.

Abstract: An optical waveguide device including an electro-optical crystal substrate having a top surface and a bottom surface; an optical waveguide path formed within a surface of the electro-optical crystal substrate; at least one electrode positioned above the optical waveguide path for applying an electric field to the optical waveguide path; and a silicon titanium oxynitride layer and a connecting layer for interconnecting the silicon titanium oxynitride layer to another surface of the electro-optical crystal substrate that is opposite to the surface in which the optical waveguide path is formed.

Abstract: An optical waveguide device including an electro-optical crystal substrate having a top surface and a bottom surface; an optical waveguide path formed within a surface of the electro-optical crystal substrate; at least one electrode positioned above the optical waveguide path for applying an electric field to the optical waveguide path; and a silicon titanium oxynitride layer and a connecting layer for interconnecting the silicon titanium oxynitride layer to another surface of the electro-optical crystal substrate that is opposite to the surface in which the optical waveguide path is formed.

Abstract: Featured is a high power, broadband superfluorescent source with very low relative intensity noise (RIN) including a seed source, a modulator operably coupled to the seed source and a polarization maintaining (PM) amplifier operably coupled to the modulator. The output of the seed source is processed in the modulator so the modulator outputs a polarized optical output to the PM amplifier. The PM amplifier amplifies the modulated, polarized optical output so as to provide an amplified polarized optical output therefrom. Also featured is a feedback circuit operably coupled to the PM amplifier to control the transmission of the modulator so as to minimize the amplitude fluctuations in the output signal. Such a source is advantageous in high precision fiber optical rotation sensors and multiplexed strain sensing arrays.

Abstract: A traveling wave, linearized, modulator device includes: an optical waveguide disposed on a substrate and consisting of an input-output portion, a terminal portion and a plurality of arms disposed between and connected to the other portions. A first arm has an optical characteristic that varies responsive to supplying of an electric field thereto. A reflector (e.g., mirror) located at the distal end of the terminal portion of the optical waveguide causes light entering the input-output portion and propagating through the waveguide to be reflected back through the waveguide so as to exit through the input-output portion. A traveling wave electrode structure disposed on the substrate terminates in an open circuit substantially at the distal end of the terminal portion of the waveguide. The electrode structure includes an electrode disposed on the first arm so as to supply an electric field to that arm responsive to an electrical voltage being supplied to the electrode.

Abstract: An optical modulator includes a substrate having an electrooptic effect, an optical waveguide having first and second cascading portions in the substrate, and transmitting an optical field, a first coplanar strip electrode having a first part over the first cascading portion and second and third parts extending beyond the first cascading portion, wherein the first part is approximately perpendicular to the second and third parts and has a width substantially the same as the first cascading portion, a second coplanar strip electrode having a first part over the second cascading portion and second and third parts to extend beyond the second cascading portion, and the first part being approximately perpendicular to the second and third parts, and a voltage source supplying a voltage to the first coplanar strip electrode, wherein the second coplanar strip electrode is grounded and is symmetrical to the first coplanar strip electrode.

Abstract: A Mach-Zehnder Interferometer having a waveguide including an input portion for receiving an optical signal and having a first channel width, a first splitter for separating the optical signal into at least first and second paths, a first arm for the first path and having a second channel width that supports a single transverse optical mode, a second arm for the second path and having a third channel width that supports a single transverse optical mode, a second splitter portion for combining optical signals of the at least first and second paths, an output portion for transmitting a resultant combination of optical signals from the second splitter and having a fourth channel width, and wherein the second channel width is larger than the fourth channel width.

Abstract: An optical modulator includes a substrate having an electrooptic effect, an optical waveguide having first and second cascading portions in the substrate, and transmitting an optical field, a first coplanar strip electrode having a first part over the first cascading portion and second and third parts extending beyond the first cascading portion, wherein the first part is approximately perpendicular to the second and third parts and has a width substantially the same as the first cascading portion, a second coplanar strip electrode having a first part over the second cascading portion and second and third parts to extend beyond the second cascading portion, and the first part being approximately perpendicular to the second and third parts, and a voltage source supplying a voltage to the first coplanar strip electrode, wherein the second coplanar strip electrode is grounded and is symmetrical to the first coplanar strip electrode.

Abstract: An electrically tunable optical modulator includes a substrate having an electrooptical effect, an optical waveguide having first, second, and third cascading portions in the substrate, and transmitting an optical field, a first coplanar waveguide electrode having a first part over the first cascading portion and second and third parts extending beyond the first cascading portion, a second coplanar waveguide electrode having a fourth part over the second cascading portion and fifth and sixth parts extending beyond the second cascading portion, a third coplanar waveguide electrode having a seventh part over the third cascading portion and eighth and ninth parts extending beyond the third cascading portion, a fourth coplanar waveguide electrode, a fifth coplanar waveguide electrode formed between the first and second coplanar waveguide electrodes, respectively, a sixth coplanar waveguide electrode formed between the second and third coplanar waveguide electrodes, and a seventh coplanar waveguide electrode.

Abstract: An optical modulator includes a substrate having an electrooptic effect, an optical waveguide having first and second cascading portions in the substrate, and transmitting an optical field, a first coplanar strip electrode having a first part over the first cascading portion and second and third parts extending beyond the first cascading portion, wherein the first part is approximately perpendicular to the second and third parts and has a width substantially the same as the first cascading portion, a second coplanar strip electrode having a first part over the second cascading portion and second and third parts to extend beyond the second cascading portion, and the first part being approximately perpendicular to the second and third parts, and a voltage source supplying a voltage to the first coplanar strip electrode, wherein the second coplanar strip electrode is grounded and is symmetrical to the first coplanar strip electrode.

Abstract: A low loss coplanar waveguide horn with low drive voltage LiNbO3 modulators wherein the electrical transmission of the traveling wave electrode structure, and of the input and output coupling structures, sometimes called the “horn”, which transition the active electrode structure with microwave connectors, is maximized by an appropriate design of the horn structure. The conflicting requirements of the leaky mode loss and maintaining sufficient size to allow microwave connection, can be reconciled by an adjustment of the ground plane width, which also effects the magnitude of coupling of the guided mode to substrate modes. Control of both the maximum horn size and the width of the ground planes in particular modulator electrode structures can provide operation to 40 GHz in LiNbO3 devices with substrate thicknesses of ˜≦1.0 mm, without excess leaky mode loss. The horn structures are ≦3 mm long and the active waveguides are ˜4-5 cm long.

Abstract: This device is a broadband, electro-optic modulator comprising an exemplary coplanar waveguide (CPW) electrode structure on an exemplary Mach-Zehnder interferometer. The modulator is formed on a lithium niobate (LiNbO3) substrate that is etched so as to form ridges upon which a gold center electrode and two gold grounded waveguides are deposited upon a buffer layer of silicon dioxide (SiO2) to form a coplanar waveguide electrode structure having a waveguide mode for receiving an electrical signal propagating therethrough in a first direction with a second phase velocity to phase modulate an optical light in the optical waveguide at a frequency in the range from 0 Hz to substantially 40 GHz.

Abstract: An optical method and apparatus particularly useful as an intensity modulation system, in which two phase modulators are placed in the loop of a Sagnac interferometer. Selective placement of the modulators, and the amplitude of any modulation signal input to the modulators, varies the bandwidth and frequency response of the system. In a preferred embodiment, the ratio of the optical distances of the modulators from interferometric midpoint, and the ratio of modulation signal amplitudes, is about 3:1, which serves to broaden and flatten the frequency response of the system.

Abstract: A bulk, quasi-periodic phase-matched difference-frequency (DFG) process in field-poled LiNbO3 bulk crystal permits continuous tunability of the output radiation in the 3.0-4.1 &mgr;m wavelength range through grating rotation. DFG in QPM-LiNbO3 crystal, carried out using a Nd:YAG laser and a high power semiconductor laser at the quasi-phased matching (QPM) degeneracy point, results in an ultra wide 0.5 &mgr;m acceptance bandwidth, permitting crystal rotation-free wavelength tuning of 4.0-4.5 &mgr;m, with 0.2 mW output power at 4.5 &mgr;m.