A bias control method of a nested optical modulator includes detecting a frequency component that has a frequency equal to a frequency of a dither signal and that is included in an output of the optical modulator, with changing a voltage value of a first bias, to measure a first error-detection value, obtaining a first error-detection curve representing a relationship between the first error-detection value and the voltage of the first bias, obtaining a first correction value based on the first error-detection curve, and obtaining the first error-detection value obtained when the first bias voltage value is equal to a voltage value obtained by adding the first correction value to the first bias voltage value at a zero-crossing point of the first error-detection curve, as a first error control value. The first bias is controlled so that the first error-detection value is the first error control value.

An optical switch structure includes a substrate, a first electrical contact, a first material having a first conductivity type electrically connected to the first electrical contact, a second material having a second conductivity type coupled to the first material, and a second electrical contact electrically connected to the second material. The optical switch structure also includes a waveguide structure disposed between the first electrical contact and the second electrical contact and comprising a waveguide core coupled to the substrate and including a first material characterized by a first index of refraction and a first electro-optic coefficient and a waveguide cladding at least partially surrounding the waveguide core and including a second material characterized by a second index of refraction and a second electro-optic. The first index of refraction is greater than the second index of refraction the first electro-optic coefficient is less than the second electro-optic coefficient

An optical waveguide device includes an intermediate layer, a thin-film LN layer including X-cut lithium niobate, and a buffer layer stacked on a substrate; an optical waveguide formed in the thin-film LN layer; and an electrode for driving. The intermediate layer is formed by an upper first intermediate layer and a lower second intermediate layer, the second intermediate layer having a permittivity that is smaller than a permittivity of the first intermediate layer.

The present disclosure relates to implementations of a photonic circuit, and particularly to a photonic circuit that includes one or more matrix circuits. For example, the present disclosure relates to photonic circuit implementations of unitary matrices, and of arbitrary real and/or complex matrices factorized using unitary matrices, that utilize special generalized Mach-Zehnder interferometers (SGMZIs) as building blocks of various matrix circuit architectures.

An optical transceiver including a submount, a Mach-Zehnder Modulator (MZM), bonding wires, and a low pass filter type matching network is provided. The MZM includes an input port and an output port and disposed on the submount. The bonding wires are coupled to the submount and the MZM. The low pass filter type matching network is coupled to the bonding wires and is configured to absorb inductance of the bonding wires at a high frequency.

An optical device including: a substrate; an optical waveguide formed at the substrate; and a protective layer formed adjacent to the optical waveguide, wherein the optical waveguide includes multiple side surfaces that intersect the substrate, at least one side surface of the optical waveguide is provided with a rough surface. According to the optical device of the present invention, the light propagation loss can be reduced.

An optical transmission apparatus includes an emitter that emits an optical signal in accordance with a bias current, and a Mach-Zehnder optical modulator that optically modulates the optical signal in accordance with an electrical signal. The optical modulator includes a detector that detects a temperature inside the optical modulator, and a controller that, when detecting activation of a power supply, controls the temperature inside the optical modulator such that the temperature detected by the detector reaches a target temperature.

In order to address an issue that an unsolved problem is caused in a conventional coherent Ising machine in which a term, which expresses a magnetic field at each site, is not able to be implemented, the present invention provides an Ising model calculation device comprising a push-pull-type optical modulator in which a role corresponding to “a local magnetic field” can be implemented by adjusting an operation point. The calculation device of the present disclosure is characterized by implementing an item, which expresses a magnetic field, at each site by adding, to the conventional coherent Ising machine, a function for simulating the magnetic field item. Specifically, light having the amplitude of a predetermined sign is input in the conventional coherent Ising machine by dislocating an operation point of the push-pull-type optical modulator. When the operation point is dislocated to a + direction, DOPO into which the light is injected considerably tends to oscillate at 0 phase, and becomes reversed when the operation point is dislocated to a minus direction.

Provided is an optical control element that can minimize an optical path difference between branched waveguides while reducing a difference in structure between the branched waveguides by disposing an input portion and an output portion of an optical waveguide on the same side of a substrate on which the optical waveguide is formed. An optical control element includes a substrate 1 having an electro-optic effect, an optical waveguide 2 formed on the substrate, and a control electrode controlling a light wave propagating through the optical waveguide, in which an input portion (input light L1) and an output portion (output light L2) of the optical waveguide are formed on the same side of the substrate, the optical waveguide includes at least one Mach-Zehnder type optical waveguide portion (MZ) that has two branched waveguides (21, 22) branched from one optical waveguide and combines the two branched waveguides to form one optical waveguide, and the branched waveguides have an even number of turned-back potions (A1, A2).

A method includes depositing a crystalline magnesium oxide (MgO) seed layer directly on an amorphous insulating cladding layer by a physical vapor deposition (PVD) process, and depositing a crystalline electro-optic layer directly on the crystalline MgO seed layer.