Apparatus, circuits and methods for reducing mismatch in an electro-optic modulator are described herein. In some embodiments, a described optical includes: a splitter configured for splitting an input optical signal into a first optical signal and a second optical signal; a phase shifter coupled to the splitter; and a combiner coupled to the phase shifter. The phase shifter includes: a first waveguide arm configured for controlling a first phase of the first optical signal to generate a first phase-controlled optical signal, and a second waveguide arm configured for controlling a second phase of the second optical signal to generate a second phase-controlled optical signal. Each of the first and second waveguide arms includes: a plurality of straight segments and a plurality of curved segments. The combiner is configured for combining the first and second phase-controlled optical signals to generate an output optical signal.

Various embodiments of the present disclosure are directed towards an integrated chip including a waveguide and a heater structure. The waveguide is disposed on a substrate and comprises an active region that extends continuously along a first distance. The heater structure overlies the waveguide. The heater structure comprises a conductive structure over the active region and a vertical structure disposed between the conductive structure and the substrate. The vertical structure comprises a conductive upper vertical segment and a lower vertical segment. The conductive structure and the conductive upper vertical segment continuously laterally extend across a second distance that is greater than or equal to the first distance. The first distance is greater than a width of the conductive structure.

In a system for converting digital data into a modulated optical signal, an electrically controllable device, including a modulator having one or more actuating electrodes, provides an analog-modulated optical signal that is modulated in response to output data bits of a digital-to-digital mapping. A digital-to-digital conversion provides the mapping of input data words to the output data bits. The mapping enables adjustments to correct for non-linearities and other undesirable characteristics, thereby improving signal quality.

In a system for converting digital data into a modulated optical signal, an electrically controllable device, including a modulator having one or more actuating electrodes, provides an analog-modulated optical signal that is modulated in response to output data bits of a digital-to-digital mapping. A digital-to-digital conversion provides the mapping of input data words to the output data bits. The mapping enables adjustments to correct for non-linearities and other undesirable characteristics, thereby improving signal quality.

The spin-entangled photon emission device comprises a Fabry-Pérot resonator with a solid state optical waveguide integrated on a substrate. Preferably, the device is used in a configuration that makes it possible to tune the resonance wavelength of the Fabry-Pérot resonator by straining or otherwise adjusting the effective optical length of the waveguide. A diamond membrane is located in the Fabry-Pérot resonator. The diamond membrane comprises a photon-source capable of emitting a photon that is entangled with a spin state of the photon source. A first surface of the diamond membrane abuts to a first minor of the Fabry-Pérot resonator. The optical waveguide has a first end facet bonded to a first surface of the diamond membrane. The first mirror of the Fabry-Pérot resonator is formed by a reflector on the second surface of the diamond membrane. The second mirror of the Fabry-Pérot resonator is formed by a reflector on a second end facet of the optical waveguide or inside the optical waveguide.

The spin-entangled photon emission device comprises a Fabry-Pérot resonator with a solid state optical waveguide integrated on a substrate. Preferably, the device is used in a configuration that makes it possible to tune the resonance wavelength of the Fabry-Pérot resonator by straining or otherwise adjusting the effective optical length of the waveguide. A diamond membrane is located in the Fabry-Pérot resonator. The diamond membrane comprises a photon-source capable of emitting a photon that is entangled with a spin state of the photon source. A first surface of the diamond membrane abuts to a first minor of the Fabry-Pérot resonator. The optical waveguide has a first end facet bonded to a first surface of the diamond membrane. The first mirror of the Fabry-Pérot resonator is formed by a reflector on the second surface of the diamond membrane. The second mirror of the Fabry-Pérot resonator is formed by a reflector on a second end facet of the optical waveguide or inside the optical waveguide.

An optical phase shift circuit can include: a first Mach Zehnder lattice and a second Mach Zehnder lattice. Each Mach Zehnder lattice can have a first waveguide and a second waveguide, with a set of active phase shifters disposed along one of the waveguides and a plurality of directional coupler regions disposed along both waveguides between the active phase shifters. A first passive phase shifter can be coupled between one output path of the first Mach Zehnder lattice and one input path of the second Mach Zehnder lattice, and a second passive phase shifter can be coupled between the other output path of the first Mach Zehnder lattice and the other input path of the second Mach Zehnder lattice. Optical phase shift circuits of this kind can be used to implement phase shifters in a Generalized Mach Zehnder interferometer.

An optical phase shift circuit can include: a first Mach Zehnder lattice and a second Mach Zehnder lattice. Each Mach Zehnder lattice can have a first waveguide and a second waveguide, with a set of active phase shifters disposed along one of the waveguides and a plurality of directional coupler regions disposed along both waveguides between the active phase shifters. A first passive phase shifter can be coupled between one output path of the first Mach Zehnder lattice and one input path of the second Mach Zehnder lattice, and a second passive phase shifter can be coupled between the other output path of the first Mach Zehnder lattice and the other input path of the second Mach Zehnder lattice. Optical phase shift circuits of this kind can be used to implement phase shifters in a Generalized Mach Zehnder interferometer.

A method for providing an electric waveform at a cryogenic temperatures includes providing an optical signal, which comprises an optical waveform, guiding the optical signal into a cryogenic chamber, and converting the optical waveform of the optical signal into an electric waveform inside the cryogenic chamber.

This optical modulator includes an optical modulation element having a first optical waveguide, a second optical waveguide, a first electrode configured to apply an electric field to the first optical waveguide, and a second electrode configured to apply an electric field to the second optical waveguide; and a control unit configured to control an applied voltage between the first electrode and the second electrode. The control unit sets Vpp to 0.06×Vπ≤Vpp≤0.4×Vπ when a half-wavelength voltage of the optical modulation element is Vπ and an applied voltage width that is an amplitude of an applied voltage applied to the optical modulation element is Vpp, and sets Vn≤Vmin≤Vn+0.29×Vπ or Vn−0.29×Vπ≤Vmax≤Vn when a minimum value and a maximum value of a voltage applied to the optical modulation element are respectively Vmin and Vmax and a null point voltage of the optical modulation element is Vn.