Method and gas analyzer for measuring the concentration of a gas component in a measurement gas, a wavelength-tunable laser diode is actuated with a current, one part of the light generated by the laser diode is guided through the measurement gas to a measuring detector to generate a measuring signal, the other part of the light is guided to a monitor detector to generate a monitor signal, the current is varied in periodically consecutive scanning intervals to scan an absorption line of interest of the gas component as a function of the wavelength, the current is further modulated with a radio-frequency noise signal having a lower cut-off frequency selected as a function of the properties of the laser diode and high enough to ensure no wavelength modulation occurs and the measuring signal is correlated with the monitor signal and then evaluated to generate a measurement result.

Provided is an optical device including a radio frequency (RF) signal source configured to electrically provide an RF signal, a first diode configured to operate as a laser diode (LD) or an electro-absorption modulator (EAM) in response to the RF signal, a second diode configured to share an N region of the first diode, be serially connected to the first diode, and have a P region connected to a ground to operate as a capacitor for series push-pull operation with the first diode, and a resistor connected between the N region and the ground.

A method for physical random number generation includes the steps of: modulating the gain of a vertical-cavity surface-emitting laser periodically from the lower threshold to the upper threshold and back; maintaining the gain per round trip positive for a longer period than the round trip time of the cavity; maintaining the net gain per round trip negative for a longer period than the round trip time of the cavity, in order to create optical pulses of random amplitude; detecting the optical pulses; converting the optical pulses into electrical analog pulses; and digitising the electrical analog pulses into random numbers.

A wavelength beam combining device includes: a laser diode stack comprising a plurality of stacked laser diode bars, wherein each laser diode bar comprises a plurality of laser diodes arranged laterally in a row; a light condensing member; a diffraction grating; a resonator mirror; and an output control unit configured to control each of the laser diode bars such that, in every possible mode in which the output control unit controls each laser diode bar to operate such that one or more of the laser diodes emit laser beams and one or more of the laser diodes do not emit laser beams, the one or more laser diodes that emit laser beams are located inward of the one or more laser diodes that do not emit laser beams.

A CMOS inverter circuit is provided as a circuit to modulate a current flowing into a laser diode on the basis of a digital signal. An amplitude of a current flowing in a PMOSFET in the CMOS inverter circuit is made to contribute to an amplitude of the current flowing into the laser diode, to reduce an input amplitude.

A wavelength beam combining device includes: a light source unit comprising a plurality of laser light sources, each being configured to emit a laser beam with a predetermined wavelength width; a light condensing member configured to condense the laser beams emitted from the light source unit; a diffraction grating on which the laser beams condensed by the light condensing member are incident; a resonator mirror disposed in an optical path of a diffracted beam from the diffraction grating; and an output control unit configured to turn off, among the plurality of laser light sources, at least laser light sources located farthest from an optical axis of the light condensing member, to reduce an output of the wavelength beam combining device relative to an output of the wavelength beam combining device when all the plurality of laser light sources are turned on.

An optical device includes a light-emitting device integrated with a memory device. The memory device include a first electrode and a second electrode, and the light-emitting device includes a third electrode and the second electrode. In such configuration, a first voltage between the second electrode and the third electrode causes the light-emitting device to emit light of a first wavelength, and a second voltage between the first electrode and the second electrode while the memory device is at OFF state causes the light-emitting device to emit light of a second wavelength shorter than the first wavelength or while the memory device is at ON state causes the light-emitting device to emit light of a third wavelength longer than the first wavelength.

A laser transmitter including a waveform controller arranged to generate a waveform script having at least one of a pulse repetition frequency setting, a pulse duration setting, and a pulse amplitude pre-warp setting. The transmitter also includes an optical waveform generator arranged to: i) receive the waveform script, ii) generate pre-warped signal pulses based on the waveform script to compensate for gain distortion effects of a laser power amplifier, and iii) output the pre-warped signal pulses. The laser power amplifier is arranged to: i) receive the pre-warped signal pulses, ii) receive a continuous wave signal, and iii) output amplified signal pulses that maintain a substantially constant drive intensity at the input of a non-linear wavelength converter. The non-linear wavelength converter is arranged to receive the amplified signal pulses and emit wavelength-converted pulses.

An optical semiconductor device includes an optical semiconductor chip in which at least one optical element is formed in a semiconductor substrate, and an extended wire pattern that is connected to a first electrode and a second electrode of the optical element and that extends outside the optical semiconductor chip. The first electrode and the second electrode of the optical semiconductor device are formed on the front surface side of the optical semiconductor chip, and the extended wire pattern is disposed on the front surface of the optical semiconductor chip or disposed at a position apart from the front surface.

An illuminating and wireless communication device includes a base; a shell attached to the base and forming a closed chamber; a laser diode located inside the closed chamber and configured to generate visible light; and a photodetector located inside the closed chamber and configured to detect incoming light. A parameter of the generated visible light is modulated to encode information.