A wavelength converter includes a first optical layer, a second optical layer, and a pixel array positioned between the first optical layer and the second optical layer. A pixel in the pixel array includes a first device to convert incident invisible light to an electrical signal and a second device that converts the electrical signal into visible light.

It is provided a vectorial network analyzer, comprising an input and output measuring device; a beat source for generating an optical beat signal; an optical transmission device which divides the optical beat signal into at least one first and one second partial signal, wherein the transmission device conducts the first partial signal to at least one terahertz transmitter and the second partial signal to at least one terahertz receiver and/or to at least one terahertz reference receiver; and a phase changing unit for varying the phase of the first and/or the second partial signal of the optical beat signal.

A multi-channel light detection and ranging system includes a plurality of active channels, each comprising a photosensitive element arranged to be exposed to light and an analog front end circuit arranged for receiving a signal from the photosensitive element. A compensation channel comprises a compensation element and an analog front end circuit arranged for receiving signals from the compensation capacitor. A processing unit arranged for receiving signals from the active channels and the compensation channel, deriving at a compensation signal from the signal received from the compensation channel, and compensating for the crosstalk interference and/or the interference common to the analog front end circuits of the active channels, using the compensation signal.

A laser interferometer includes a light source that emits first laser light, an optical modulator that includes a vibrator and modulates the first laser light by using the vibrator to generate second laser light including a modulated signal, a photodetector that receives interference light between third laser light including a sample signal generated by reflecting the first laser light on an object and the second laser light to output a light reception signal, and a demodulation circuit that performs a demodulation process for demodulating the sample signal from the light reception signal, and the demodulation circuit intermittently performs the demodulation process.

A laser interferometer includes a light source that emits first laser light, an optical modulator that includes a vibrator and modulates the first laser light by using the vibrator to generate second laser light including a modulated signal, a photodetector that receives interference light between third laser light including a sample signal generated by reflecting the first laser light on an object and the second laser light to output a light reception signal, and a demodulation circuit that performs a demodulation process for demodulating the sample signal from the light reception signal, and the demodulation circuit intermittently performs the demodulation process.

A pluggable optical connector is configured to be insertable into and removable from an optical communication apparatus, and to be capable of communicating a modulation signal and a data signal with the optical communication apparatus. A wavelength-tunable light source is configured to output an output light and a local oscillation light. An optical transmission unit is configured to output an optical signal generated by modulating the output light in response to the modulation signal. An optical reception unit is configured to demodulate an optical signal received by using the local oscillation light to the data signal. Pluggable optical receptors are configured in such a manner that an optical fiber is insertable into and removable from the pluggable optical receptors, and configured to be capable of outputting the optical signal to the optical fiber and transferring the optical signal received thorough the optical fiber to the optical reception unit.

A pluggable optical connector is configured to be insertable into and removable from an optical communication apparatus, and to be capable of communicating a modulation signal and a data signal with the optical communication apparatus. A wavelength-tunable light source is configured to output an output light and a local oscillation light. An optical transmission unit is configured to output an optical signal generated by modulating the output light in response to the modulation signal. An optical reception unit is configured to demodulate an optical signal received by using the local oscillation light to the data signal. Pluggable optical receptors are configured in such a manner that an optical fiber is insertable into and removable from the pluggable optical receptors, and configured to be capable of outputting the optical signal to the optical fiber and transferring the optical signal received thorough the optical fiber to the optical reception unit.

A pluggable electric connector is configured to be insertable into and removable from an optical communication apparatus. An optical output module outputs an optical signal and a local oscillation light. An optical reception module outputs a communication data signal generated by demodulating using the local oscillation light. A pluggable optical receptor is configured in such a manner that optical fibers are insertable thereinto and removable therefrom. A first optical fiber is connected between the optical output module and the pluggable optical receptor. A second optical fiber is connected between the optical output module and the optical reception module. A third optical fiber is connected between the optical reception module and the pluggable optical receptor. Optical fiber housing means winds extra lengths of the first to third optical fibers around a guide.

A coherent optical mixer circuit is provided that can measure a phase error without requiring a step of cutting away a delay circuit. Odd-numbered or even-numbered two of four inputs of an 4-input-and-4-output multimode interference circuit are connected to an input mechanism. The four outputs of the multimode interference circuit are all connected to an output mechanism to the exterior. Other two inputs of the multimode interference circuit are connected to two monitor waveguides. One of the monitor waveguide is longer than the other to configure a light delay circuit. The monitor waveguides constituting the light delay circuit are connected to the respective outputs of a 2-branched light splitter. The 2-branched light splitter has an input connected to a monitor light input mechanism from the exterior via a monitor input waveguide.

A coherent optical mixer circuit is provided that can measure a phase error without requiring a step of cutting away a delay circuit. Odd-numbered or even-numbered two of four inputs of an 4-input-and-4-output multimode interference circuit are connected to an input mechanism. The four outputs of the multimode interference circuit are all connected to an output mechanism to the exterior. Other two inputs of the multimode interference circuit are connected to two monitor waveguides. One of the monitor waveguide is longer than the other to configure a light delay circuit. The monitor waveguides constituting the light delay circuit are connected to the respective outputs of a 2-branched light splitter. The 2-branched light splitter has an input connected to a monitor light input mechanism from the exterior via a monitor input waveguide.