A broadband light source apparatus, and corresponding method, includes a broadband light source configured to provide broadband source light characterized by a source wavelength spectrum. The apparatus also includes a broadband optical filter including both a polarization changer with a length, as well as an exit polarizer. The broadband optical filter receives the source light and delivers broadband output light characterized by an output wavelength spectrum that is a function of the source wavelength spectrum and the polarization changer length and has an output centroid wavelength. The polarization changer length is configured to minimize a thermal sensitivity of the output centroid wavelength. The filter can be configured in view of a particular source wavelength spectrum to thermally stabilize the centroid wavelength and to maximize relative integrated output power passively with respect to ambient temperature fluctuations.

A small and inexpensive optical modulator having suppressed temperature drift and high reliability and an optical transmission device using the same are provided. The optical modulator includes an optical waveguide substrate where an optical waveguide is formed; a control electrode that is provided on the optical waveguide substrate and applies an electric field to the optical waveguide; and a relay substrate that is disposed in the vicinity of the optical waveguide substrate and includes electrical wirings that relay electrical signals from the outside to the control electrode. The control electrode includes a signal electrode. The optical modulator comprises terminating units that include terminal resistors that terminate the signal electrode. At least a part of the terminating units are provided on the relay substrate.

A method and circuit for operating a liquid crystal device, LCD, based polarisation rotator. The method comprises the steps of tracking a capacitance value of the LCD rotator; and controlling a driver setting to the LCD rotator based on the tracked capacitance value to achieve temperature independent operation.

A liquid-crystal variable retarder has first and second liquid-crystal cells with respective first and second thicknesses, the second thickness being less than the first thickness. A feedback sensor provides a feedback signal indicative of a retardance of the liquid-crystal variable retarder. A controller is coupled to the feedback sensor and the first and second liquid-crystal cells. The controller is operable to apply a first signal to the first liquid-crystal cell based on a target retardance trajectory and a feedforward control model. The controller applies a second signal to the second liquid-crystal cell based on the feedback signal and the target retardance trajectory.

An optical module according to one embodiment includes: an optical element having a first side, a second side, and a third side; a housing; a thermoelectric cooler with the optical element being mounted on the thermoelectric cooler; a driving circuit arranged on the side of the first side of the optical element; a first bonding pad arranged on the side of the second side of the optical element; and a first wiring pattern provided on the frame body of the housing and connected to the first bonding pad of the optical element through the first bonding wiring, wherein the thermoelectric cooler has a plurality of Peltier elements arranged with spacings. A spacing between the plurality of Peltier elements located on the side of the second side is narrower than a spacing between the plurality of Peltier elements located in the center of the optical element.

A system includes (a) an optical device having a GRIN LC lens, the GRIN LC lens including a liquid crystal layer, (b) a sensor configured to assess an attribute of the liquid crystal layer, (c) a heat source, and (d) a controller configured to mediate heat flow between the heat source and the liquid crystal layer based on a signal provided by the sensor.

Provided is an optical modulator module in which an occurrence of an error burst or an increase of an optical loss caused by a vapor phase transportation material can be effectively suppressed. The optical modulator module includes a substrate 1 that has a pyroelectric effect, an optical waveguide 2 that is formed on a principal surface of the substrate 1, a conductive film (not illustrated) that is formed on the substrate 1, and control electrodes (31 to 33) that control a light wave propagated through the optical waveguide 2. In the optical modulator module, the light wave is input to an end portion 21 of the optical waveguide (or is output from the end portion 21 of the optical waveguide) by a space optical system (not illustrated). Adsorption means 4 for adsorbing a vapor phase transportation material is disposed in the vicinity of the end portion 21 of the optical waveguide.

A device, includes: a ring waveguide; a diode comprising a junction extending at least partly in the ring waveguide; and a first circuit configured to supply a signal representative of a leakage current in the diode.

A fringe projector apparatus includes: a phase modulator having a first waveguide, a second waveguide, and a plurality of heaters including a first heater and a second heater, wherein the first and second waveguides and the plurality of heaters are provided on a single substrate, and wherein the first heater heats the first waveguide and the second heater heats a position away from the first waveguide; a light source that generates a light beam to be input to the first waveguide and the second waveguide; and a controller that controls a phase difference between the first waveguide and the second waveguide by changing an electric power consumption of the first heater under a condition that a total electric power consumption of the plurality of heaters is constant.

Provided is an optical modulator capable of effectively dispersing and releasing heat generated by termination resistors, improving the reliability of a termination substrate including the termination resistors, and reducing influence of heat on an optical waveguide. In an optical modulator including an optical waveguide substrate on which an optical waveguide is formed, a signal electrode is provided on the optical waveguide substrate for applying an electric field, a termination resistor terminating the signal electrode, and a termination substrate on which the termination resistor is disposed, at least a plurality of the termination resistors are provided for a single termination substrate, and for preventing heat generated by the termination resistor from being concentrated on a local portion in the termination substrate or conducted to the optical waveguide substrate, a ground electrode provided on the termination substrate and electrically connected to the termination resistor is formed to be thicker than 0.1 m.