In example implementations, an optical gate is provided. The optical gate receives at least one optical signal via a waveguide of an optical memory gate. The optical gate compares a wavelength of the at least one optical signal to a resonant wavelength associated with a resonator. When the wavelength of the at least one optical signal matches the resonant wavelength, a value that is stored in the resonator is read out via the at least one optical signal. Then, the at least one optical signal with the value that is read out is transmitted out of the optical gate.

An optical diode (1) comprising an optical wave guide for guiding light, preferably of a light mode, with a vacuum wavelength λ.sub.0, wherein the optical wave guide has a wave guide core (2, 3, 14) with a first index of refraction (n.sub.1), and the wave guide core (2, 3, 14) is surrounded by at least one second optical medium which has at least one second index of refraction (n2), wherein n.sub.1>n.sub.2 applies, wherein the wave guide core (2, 3, 14) has at least in sections a smallest lateral dimension (7) which is a smallest dimension of a cross section (6) perpendicular to a propagation direction (5) of the light in the wave guide core (2, 3, 14), wherein the smallest lateral dimension (7) is greater than or equal to λ.sub.0/(5*n.sub.1) and less than or equal to 20*λ.sub.0/n.sub.1, wherein the optical diode (1) additionally comprises at least one absorber element (10, 11, 15, 16) which is arranged in a near field, wherein the near field consists of the electromagnetic field of the light of the vacuum wavelength λ.sub.0 in the wave guide core (2, 3, 14) and outside of the wave guide core (2, 3, 14) up to a standard interval (12) of 5*λ.sub.0, wherein the standard interval (12) is measured starting from one surface (8) of the wave guide core (2, 3, 14) forming an optical interface and in a direction perpendicular to the surface (8). The invention provides that the at least one absorber element (10, 11, 15, 16) for the light of the vacuum wavelength λ.sub.0 has a strongly different absorption for left circular polarization (σ.sup.−) and the right circular polarization (σ.sup.+).

Examples described herein relate to an optical device, such as, a ring resonator, that includes a ring waveguide. The ring resonator includes a ring waveguide to allow passage of light therethrough. Further, the ring resonator includes a modulator formed along a first section of the circumference of the ring waveguide to modulate the light inside the ring waveguide based on an application of a first reverse bias voltage to the modulator. Moreover, the ring resonator includes an avalanche photodiode (APD) isolated from the modulator and formed along a second section of the circumference of the ring waveguide to detect the intensity of the light inside the ring waveguide based on an application of a second reverse bias voltage to the APD. The second section is shorter than the first section, and the second reverse bias voltage is higher than the first reverse bias voltage.

A first portion of incoming light and a second portion of incoming light travel in opposite directions within a first optical waveguide. A ring resonator in-couples the first portion of incoming light and the second portion of incoming light from the first optical waveguide, such that the first portion of incoming light and the second portion of incoming light travel in opposite directions within the ring resonator. A second optical waveguide is disposed to in-couple the first portion of incoming light and the second portion of incoming light couple from the ring resonator, such that the first portion of incoming light and the second portion of incoming light travel in opposite directions within the second optical waveguide away from the ring resonator. One or more photodetector(s) are optically connected to receive the first portion of incoming light and the second portion of incoming light from the second optical waveguide.

In some embodiments, the present disclosure relates to a modulator device that includes an input terminal configured to receive impingent light. A first waveguide has a first output region and a first input region that is coupled to the input terminal. A second waveguide is optically coupled to the first waveguide and has second input region and a second output region that is coupled to the input terminal. An output terminal coupled to the first output region of the first waveguide and the second output region of the second waveguide is configured to provide outgoing light that is modulated. A heater structure is configured to provide heat to the first waveguide to induce a temperature difference between the first and second waveguides. A gas-filled isolation structure is proximate to the heater structure and is configured to thermally isolate the second waveguide from the heat provided to the first waveguide.

Examples described herein relate to an optical device having a photonic-crystal lattice structure. In some examples, the optical device may include a substrate having a photonic-crystal lattice structure. The optical device may further include an optical waveguide formed in the photonic-crystal lattice structure and a defect cavity formed in the photonic-crystal lattice structure and optically coupled to the optical waveguide. Furthermore, the optical device may include a refractive index tuning structure adjacent to the defect cavity in the photonic-crystal lattice structure.

An electro-optical chip includes an optical input port, an optical output port, and an optical waveguide having a first end optically connected to the optical input port and a second end optically connected to the optical output port. The optical waveguide includes one or more segments. Different segments of the optical waveguide extends in either a horizontal direction, a vertical direction, a direction between horizontal and vertical, or a curved direction. The electro-optical chip also includes a plurality of optical microring resonators is positioned along at least one segment of the optical waveguide. Each microring resonator of the plurality of optical microring resonators is optically coupled to a different location along the optical waveguide. The electro-optical chip also includes electronic circuitry for controlling a resonant wavelength of each microring resonator of the plurality of optical microring resonators.

An all fiber wavelength selective coupler provides wavelength selective transfer of optical energy between two or more separated waveguides. The coupler includes signal cores that are separated enough that they can be fusion spliced to standard fibers as lead-in and lead-out pigtails. A bridge between the signal cores facilitates transfer of the optical energy through a process of evanescent coupling. In one example, the bridge is formed of a series of graded index cores.

Microwave-to-optical transducers in an optical ring resonator having intracavity grating to split a single resonance order are provided. In one aspect, a microwave-to-optical transducer includes: an optical ring resonator with intracavity grating; and a microwave signal waveguide optically coupled to the optical ring resonator with the intracavity grating. Microwave-to-optical transducers having multiple pump photon optical ring resonators and multiple signal photon optical ring resonators optically coupled to the optical ring resonator with the intracavity grating are also provided, as is a method of forming a microwave-to-optical transducer, and a method for microwave-optical transduction.

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for tuning photonic device performance. In one aspect, a method includes receiving an initial photonic device configuration including multiple coupling structures and multiple photonic components. A first amount of light coupling between a first photonic component and a second photonic component of the multiple photonic components is received, which depends upon a subset of the coupling structures that are located between the first photonic component and the second photonic component. One or more coupling structures of the subset of coupling structures located between the first photonic component and the second photonic component are determined to be removed to cause the light coupling between the first photonic component and the second photonic component to change from the first amount of coupling to a target amount of coupling.