A temperature compensated carrier effect switching cell controls phase shifts to compensate for phase errors induced by temperature difference between arms of the switching cell. The temperature difference may be generated by driving the carrier effect region of the switching cell. Temperature sensors within the arms of the switching cell provide signals indicative of the temperature difference.

An electro-optic modulator of a test and measurement system. The electro-optic modulator includes a first electrode, a second electrode with identical electrical characteristics as the first electrode and an optical waveguide between the first electrode and the second electrode. The first electrode and the second electrode present a balanced load to a device under test.

A first resistor connected in parallel to a semiconductor optical modulator having first ends, the first resistor and first ends connected to a reference potential. A first end of a first transmission line is connected to second ends of the semiconductor optical modulator and the first resistor. A second transmission line is connected in series to the first transmission line and has an impedance lower than that of the first resistor. A first end of the second transmission line is connected to a second end of the first transmission line. A third transmission line is connected in series to the first and second transmission lines and has an end connected to a second end of the second transmission line, and has an impedance equal to that of the first transmission line. A second resistor and a capacitor are connected in series between the third transmission line and the reference potential.

Multilevel optical intensity modulation high in accuracy is performed using electro-absorption optical modulators. There is provided a plurality of EA modulators connected in series in a path of an optical signal from a light source, and a multilevel-coded modulated optical signal is generated by modulating an intensity of an input optical signal from the light source based on a modulation signal using the EA modulators. Each of the EA modulators is switched between an ON state and an OFF state of optical absorption in accordance with the modulation signal. Regarding an extinction ratio of the ON state to the OFF state in each of the EA modulators, the EA modulators have respective values difference from each other, and are arranged in ascending order of the extinction ratio from the light source side.

An optical communication device is configured to include: a laser diode that outputs light; an EA modulator including a cathode and an anode, to modulate the light output from the laser diode on the basis of a high-frequency signal applied between the cathode and the anode; a resistor connected between the cathode and the anode; and a pattern line connected in series with the resistor and having an inductance component, in which each of the laser diode and the EA modulator is formed on a front surface of the high-frequency line substrate or a back surface of the high-frequency line substrate, and the pattern line is formed on a side face of the high-frequency line substrate.

A smart window control device controls transmittance of a smart window provided as a window of a space where a temperature is controlled by an air conditioning system in accordance with a set temperature. The smart window control device includes a processor, and a memory storing program instructions that cause the processor to obtain a predicted value of external environment information about outside of the space in an interval between a first time and a second time, the second time being when a predetermined time period has elapsed from the first time, calculate transition of the temperature of the space in the interval based on the predicted value of the external environment information in the interval, and control the transmittance of the smart window so that the temperature of the space in the interval transitions based on the calculated transition of the temperature.

Provided is an optical modulator in which low-voltage drive and a stable modulation characteristic are secured over a wide bandwidth. An optical modulator includes: a substrate 10; an optical waveguide (not shown) formed in the substrate 10; a modulation electrode (a signal electrode 11 and a ground electrode 12) for modulating light waves propagating through the optical waveguide; and an external signal line (not shown, only a connection connector 4 is shown) which is provided outside the substrate and supplies a modulation signal to the modulation electrode, in which an impedance value of the modulation electrode in an active region S in which an electric field formed by the modulation electrode is applied to the optical waveguide is set to be lower than an impedance value of the external signal line, and an impedance adjustment part 21 having an impedance adjustment function with respect to mainly a modulation signal in a low-frequency area and configured of a lumped-constant circuit, and an impedance matching line L having an impedance adjustment function with respect to mainly a modulation signal in a high-frequency area are disposed between the external signal line and the active region of the modulation electrode.

The present invention describes a semiconductor interferometric device capable of modulating an electromagnetic wave by modulating the carrier concentration inside a semiconductor device. The variation of the carrier concentration within the device causes the variation of the physical properties inside the semiconductor material leading to a shift of the reflected and absorbed spectrums. One or more rays are generated within the device so as to operate the device through interference effects. The present invention may be utilized for an antenna or for beam steering purposes comprising an array of semiconductor interferometric reflecting devices. Furthermore the same principle could be utilized to generate tunable meta-surfaces, so as to modulate phase, amplitude or polarization of an incident electromagnetic wave.

In order to provide an optical transmitter in which a temperature sensor does not need to be separately provided, and further, size reduction can be made, in the present invention, a detection circuit detecting output fluctuation due to temperature dependency of a transmission driver is provided in an optical transmitter including at least one of the transmission driver.

An electro-optic beam controller, material processing apparatus, or optical amplifier, and corresponding methods, can include an actively controlled, waveguide-based, optical spatial mode conversion device. The conversion device can include a coupler, which can be a photonic lantern, configured to combine light beams into a common light beam; a sensor configured to measure at least one characteristic of the common light beam; and a controller configured to modulate optical parameters of the individual, respective light beams to set one or more spatial modes of the common light beam. Actively controlled and modulated devices can be used to maintain a stable, diffraction-limited beam for use in an amplification, communications, imaging, laser radar, switching, or laser material processing system. Embodiments can also be used to maintain a fundamental or other spatial mode in an optical fiber even while scaling to kilowatt power.