Abstract: Kerr and electro-optic frequency comb generation in integrated lithium niobate devices is provided. In various embodiments, a microring resonator comprising lithium niobate is disposed on a thermal oxide substrate. The microring resonator has inner and outer edges. Electrodes are positioned along the inner and outer edges of the microring resonator. The electrodes are adapted to modulate the refractive index of the microring. A pump laser is optically coupled to the microring resonator. The microring resonator is adapted to emit an electro-optical frequency comb when receiving a pump mode from the pump laser and when the electrodes are driven at a frequency equal to a free-spectral-range of the microring resonator.

Abstract: A velocity mismatch between optical signals and microwave electrical signals in electro-optic devices, such as modulators, may be compensated by utilizing different lengths of bends in the optical waveguides as compared to the microwave electrodes to match the velocity of the microwave signal propagating along the coplanar waveguide to the velocity of the optical signal. To ensure the electrode bends do not affect the light in the optical waveguide bends, the electrode may have to be rerouted, e.g. above or below, the optical waveguide layer. To ensure that the pair of optical waveguides have the same optical length, a waveguide crossing may be used to cross the first waveguide through the second waveguide.

Abstract: An optical device including a waveguide and an electrode is described. The waveguide includes at least one optical material having an electro-optic effect. The electrode includes a channel region and extensions protruding from the channel region. The extensions are closer to a portion of the waveguide than the channel region is.

Abstract: A velocity mismatch between optical signals and microwave electrical signals in electro-optic devices, such as modulators, may be compensated by utilizing different lengths of bends in the optical waveguides as compared to the microwave electrodes to match the velocity of the microwave signal propagating along the coplanar waveguide to the velocity of the optical signal. To ensure the electrode bends do not affect the light in the optical waveguide bends, the electrode may have to be rerouted, e.g. above or below, the optical waveguide layer. To ensure that the pair of optical waveguides have the same optical length, a waveguide crossing may be used to cross the first waveguide through the second waveguide.

Abstract: Electro-optic devices for classical and quantum microwave photonics are provided. In various embodiments, a device comprises: a waveguide; a first ring resonator; a second ring resonator, the second ring resonator evanescently coupled to the first ring resonator and to the waveguide; a first pair of electrodes, one of the first pair of electrodes disposed within the first ring resonator and the other of the first pair of electrodes disposed without the first ring resonator; a second pair of electrodes, one of the second pair of electrodes disposed within the second ring resonator and the other of the second pair of electrodes disposed without the second ring resonator; a microwave source electrically coupled to the first and second pairs of electrodes; a bias port electrically coupled to the first and second pairs of electrodes and configured to sweep a frequency band.

Abstract: An integrated electro-optic frequency comb generator based on ultralow loss integrated, e.g. thin-film lithium niobate, platform, which enables low power consumption comb generation spanning over a wider range of optical frequencies. The comb generator includes an intensity modulator, and at least one phase modulator, which provides a powerful technique to generate a broad high power comb, without using an optical resonator. A compact integrated electro-optic modulator based frequency comb generator, provides the benefits of integrated, e.g. lithium niobate, platform including low waveguide loss, high electro-optic modulation efficiency, small bending radius and flexible microwave design.

Abstract: An optical modulator that uses adiabatic tapers to change the width of the waveguides between multimode waveguides and single mode waveguides on a low-loss, e.g. thin-film lithium niobate, electro-optic platform. The architecture enables the utilization of the fundamental mode of multimode wide optical waveguides that have lower optical propagation loss without sacrificing the benefit of the signal integrity and ease of control of single mode operation.

Abstract: An integrated electro-optic frequency comb generator based on ultralow loss integrated, e.g. thin-film lithium niobate, platform, which enables low power consumption comb generation spanning over a wider range of optical frequencies. The comb generator includes an intensity modulator, and at least one phase modulator, which provides a powerful technique to generate a broad high power comb, without using an optical resonator. A compact integrated electro-optic modulator based frequency comb generator, provides the benefits of integrated, e.g. lithium niobate, platform including low waveguide loss, high electro-optic modulation efficiency, small bending radius and flexible microwave design.

Abstract: Low loss fiber-to-chip interfaces for lithium niobate photonic integrated circuits are provided. An optical circuit includes a waveguide comprising an electro-optical material. The waveguide includes an elevated ridge and a slab underlying the elevated ridge, the elevated ridge and the slab extending along a central axis toward an optical interface. The elevated ridge and the slab each have a plurality of cross-sections along the central axis, each cross-section having a width measured perpendicular to the central axis, wherein the width of elevated ridge is smaller than the width of the slab for every cross-section along the central axis. The elevated ridge includes a tapered portion having a first taper, wherein the cross-section of the elevated portion decreases along the central axis toward the optical interface. The slab includes a tapered portion having a second taper, wherein the cross-section of the slab decreases along the central axis toward the optical interface.

Abstract: An interface for an optical modulator and the optical modulator are described. The interface includes first and second differential line pairs. The first differential line pair has a first negative line and a first positive line arranged on opposing sides of a first waveguide. The first negative line is on a distal side of the first waveguide relative to a second waveguide. The first positive line is on a proximal side of the first waveguide relative to the second waveguide. The second differential line pair has a second negative line and a second positive line arranged on opposing sides of the second waveguide. The second negative line is on a distal side of the second waveguide relative to the first waveguide. The second positive line is on a proximal side of the second waveguide relative to the first waveguide. The first and second waveguides each include lithium niobate and/or lithium tantalate.

Abstract: An optical modulator that uses adiabatic tapers to change the width of the waveguides between multimode waveguides and single mode waveguides on a low-loss, e.g. thin-film lithium niobate, electro-optic platform. The architecture enables the utilization of the fundamental mode of multimode wide optical waveguides that have lower optical propagation loss without sacrificing the benefit of the signal integrity and ease of control of single mode operation.

Abstract: A velocity mismatch between optical signals and microwave electrical signals in electro-optic devices, such as modulators, may be compensated by utilizing different lengths of bends in the optical waveguides as compared to the microwave electrodes to match the velocity of the microwave signal propagating along the coplanar waveguide to the velocity of the optical signal. To ensure the electrode bends do not affect the light in the optical waveguide bends, the electrode may have to be rerouted, e.g. above or below, the optical waveguide layer. To ensure that the pair of optical waveguides have the same optical length, a waveguide crossing may be used to cross the first waveguide through the second waveguide.

Abstract: An optical device is described. At least a portion of the optical device includes lithium niobate and is fabricated utilizing ultraviolet lithography. In some aspects the at least the portion of the optical device is fabricated using deep ultraviolet lithography. In some aspects, the short range root mean square surface roughness of a sidewall of the at least the portion of the optical device is less than ten nanometers. In some aspects, the at least the portion of the optical device has a loss of not more than 2 dB/cm.

Abstract: Optical devices and their fabrication from thin film lithium niobate are provided. In some embodiments, an optical device includes a substrate and an optical waveguide disposed on the substrate. The optical waveguide comprises lithium niobate. The optical waveguide has a central ridge extending laterally along the substrate. A pair of electrodes is disposed on opposite sides of the central ridge of the optical waveguide.

Abstract: Reconfigurable electro-optic frequency shifters are provided. In various embodiments, the optical frequency shifter comprises a continuous optical spectrum medium; a discrete optical spectrum medium optically coupled to the continuous optical spectrum medium; and a tunable element operably coupled to the discrete optical spectrum medium, wherein: the discrete optical spectrum medium has N optical modes (I:{i1 . . . iN}), said optical modes being ordered and equidistant in a frequency domain, wherein N is an integer equal to or greater than 3, each of the optical modes (in?I) having a coupling constant ?e,n with respect to the continuous optical spectrum medium, wherein at least one of the coupling constants ?e,n is different from the other coupling constants, the optical modes (I) having a coupling constant ? with respect to one another, wherein the tunable element is configured to control the coupling constant ?.

Abstract: An optical device is described. At least a portion of the optical device includes lithium niobate and is fabricated utilizing ultraviolet lithography. In some aspects the at least the portion of the optical device is fabricated using deep ultraviolet lithography. In some aspects, the short range root mean square surface roughness of a sidewall of the at least the portion of the optical device is less than ten nanometers. In some aspects, the at least the portion of the optical device has a loss of not more than 2 dB/cm.

Abstract: An optical device is described. At least a portion of the optical device includes ferroelectric non-linear optical material(s) and is fabricated utilizing ultraviolet lithography. In some aspects the at least the portion of the optical device is fabricated using deep ultraviolet lithography. In some aspects, the short range root mean square surface roughness of a sidewall of the at least the portion of the optical device is less than ten nanometers. In some aspects, the at least the portion of the optical device has a loss of not more than 2 dB/cm.

Abstract: An optical device is described. At least a portion of the optical device includes lithium niobate and is fabricated utilizing ultraviolet lithography. In some aspects the at least the portion of the optical device is fabricated using deep ultraviolet lithography. In some aspects, the short range root mean square surface roughness of a sidewall of the at least the portion of the optical device is less than ten nanometers. In some aspects, the at least the portion of the optical device has a loss of not more than 2 dB/cm.

Abstract: Electro-optic devices for classical and quantum microwave photonics are provided. In various embodiments, a device comprises: a waveguide; a first ring resonator; a second ring resonator, the second ring resonator evanescently coupled to the first ring resonator and to the waveguide; a first pair of electrodes, one of the first pair of electrodes disposed within the first ring resonator and the other of the first pair of electrodes disposed without the first ring resonator; a second pair of electrodes, one of the second pair of electrodes disposed within the second ring resonator and the other of the second pair of electrodes disposed without the second ring resonator; a microwave source electrically coupled to the first and second pairs of electrodes; a bias port electrically coupled to the first and second pairs of electrodes and configured to sweep a frequency band.

Abstract: Active photonic networks on integrated lithium niobate platforms are provided. In various embodiments, a plurality of Mach-Zehnder interferometers is provided. Each Mach-Zehnder interferometer has an input and two outputs. Each Mach-Zehnder interferometer comprises at least one electrode operative to control the phase or intensity of at least one of the outputs. The plurality of Mach-Zehnder interferometers are optically interconnected. At least one controller is electrically coupled to the at least one electrode of each of the plurality of Mach-Zehnder interferometers. The controller is operative to individually control each electrode.