The first transmission line has a width perpendicular to a transmission direction. The first electrode has a width not exceeding the width. The first electrode is opposed to the first transmission line. The ground layer has a positional relationship with each portion of the first transmission line. The ground layer is next to the first transmission line on at least one side consisting of a first side along a thickness direction of the mounting substrate, and a second side and a third side with the first transmission line interposed therebetween. The first transmission line is bonded to the first electrode and has the width equivalently, at least, at a portion of the first transmission line. The portion equivalently has the positional relationship with the ground layer. The portion is next to the ground layer in an equivalent shape along the transmission direction.

Provided are a multilayer thin-film structure and a phase shifting device using the same. The multilayer thin-film structure includes at least one crystallization preventing layer and at least one dielectric layer that are alternately stacked. The at least one crystallization preventing layer includes an amorphous material, and a thickness of the at least one crystallization preventing layer is less than a thickness of the at least one dielectric layer.

Disclosed are structures and methods for CMOS drivers that drive silicon optical push-pull Mach-Zehnder modulators (MZMs) with twice the drive voltage per interferometer arm as with prior art designs.

An optical data transmitter in which surface-coupled reflective electro-absorption modulators are placed into different interferometer arms and operated in a manner that enables the optical data transmitter to transmit an optical output signal modulated using PAM, QPSK, or QAM modulation. In some embodiments, the optical data transmitter is configured to generate a PDM optical output signal by using two such interferometers and a quarter-wavelength plate configured to cause the output polarizations of the two interferometers to be mutually orthogonal. The electro-absorption modulators are surface-coupled in the sense that, in operation, each of these devices receives input light and outputs modulated light along a direction that is substantially orthogonal to the main plane of the device. In an example embodiment, an electro-absorption modulator includes a PIN diode comprising an MQW structure and implemented using a stack of relatively thin semiconductors layers that are parallel to the main plane of the device.

An optical modulator has an optical input port and an optical output port provided on a same end of a substrate; an optical waveguide pair formed in the substrate and configured to form a Mach-Zehnder interferometer, one end of the optical waveguide pair being connected to the optical input port and the other end of the optical waveguide pair being connected to the optical output port, the optical waveguide pair having a bending part; a groove provided along the optical waveguide pair in the bending part; and a signal electrode that applies a high-frequency electrical signal to the optical waveguide pair, wherein the signal electrode has an expanded section having an increased cross sectional area at a section intersecting the groove.

An optical modulator uses an optoelectronic phase comparator configured to provide, in the form of an electrical signal, a measure of a phase difference between two optical waves. The phase comparator includes an optical directional coupler having two coupled channels respectively defining two optical inputs for receiving the two optical waves to be compared. Two photodiodes are configured to respectively receive the optical output powers of the two channels of the directional coupler. An electrical circuit is configured to supply, as a measure of the optical phase shift, an electrical signal proportional to the difference between the electrical signals produced by the two photodiodes.

A method and apparatus for protecting an optical sensor is disclosed. A fixed filter having a fixed passband for light transmission is placed in front of the optical sensor. A programmable filter having a variable passband for light transmission is placed in front of the fixed filter. A controllable voltage source controls a voltage at the programmable filter that shifts the passband of the programmable filter from a first state in which the passband of the programmable filter is substantially the same as the passband of the fixed filter and a second state in which the passband of the programmable filter is different than the passband of the fixed filter.

A phosphor screen for a Micro-Electro-Mechanical-Systems (MEMS) image intensifier includes a wafer structure, a lattice of interior walls, a thin film phosphor layer, and a reflective metal layer. The wafer structure has a naturally opaque top layer and an active area defined within the naturally opaque top layer. The lattice of interior walls is formed, within the active area, from the naturally opaque top layer. The thin film phosphor layer is disposed in the active area, between the lattice of interior walls. The reflective metal layer that is disposed atop the thin film phosphor layer. In at least some instances, the thin film phosphor layer is a non-particle phosphor layer.

An electro-optic Mach-Zehnder modulator includes a first optical waveguide forming a first arm of the Mach-Zehnder modulator, and a second optical waveguide forming a second arm thereof. The first or second optical waveguide includes capacitive segments that are spaced apart from one another, each forming an electrical capacitor. A travelling wave electrode arrangement applies a voltage across the first or second optical waveguide. The travelling wave electrode arrangement includes waveguide electrodes arranged on the capacitive segments , an electrical line extending along a part of the first or second optical waveguide, the electrical line being arranged a distance from the waveguide electrodes, and connecting arrangements, each being assigned to one of the waveguide electrodes. Each connecting arrangement includes at least two connecting structures spaced apart from one another wherein the waveguide electrodes each are electrically connected to the electrical line via the assigned two connecting structures.

An optical modulator uses an optoelectronic phase comparator configured to provide, in the form of an electrical signal, a measure of a phase difference between two optical waves. The phase comparator includes an optical directional coupler having two coupled channels respectively defining two optical inputs for receiving the two optical waves to be compared. Two photodiodes are configured to respectively receive the optical output powers of the two channels of the directional coupler. An electrical circuit is configured to supply, as a measure of the optical phase shift, an electrical signal proportional to the difference between the electrical signals produced by the two photodiodes.