An optical transconductance varistor system having a modulated radiation source configured to provide modulated stimulus, a wavelength converter operably connected to the modulated radiation source to produce a modulated stimulus having a predetermined wavelength, and a wide bandgap semiconductor photoconductive material in contact between two electrodes. The photoconductive material is operably coupled, such as by a beam transport module, to receive the modulated stimulus having the predetermined wavelength to control a current flowing through the photoconductive material when a voltage potential is present across the electrodes.

A surface emitting laser includes: multiple active layers; a resonator including a tunnel junction between the multiple active layers; multiple reflectors sandwiching the resonator between the multiple reflectors; and an electrode pair connected to a power supply device through which a current is injected into the multiple active layers. The surface emitting laser does not oscillate a laser beam during a current injection period in which the power supply device injects the current into the multiple active layers through the electrode pair; and oscillates the laser beam during a current decrease period after the current injection period. The current injected into the multiple active layers during the current decrease period is lower than the current injected into the multiple active layers during the current injection period.

Example methods, devices, and systems for optical emission are disclosed. An example device can comprise one or more optical filters. The one or more optical filters can be configured to be coupled to an optical amplifier. The device can comprise a microresonator configured to receive an output of the one or more optical filters and output, based on parametric multiwave mixing, a frequency comb. The one or more optical filters and the microresonator can be integrated into a single chip.

An optical device and a distance measuring device capable of appropriately detecting an emission timing of oscillation light are provided. An optical device according to the present disclosure includes: a light emitting element including a semiconductor section that is included in a first resonator causing light of a first wavelength to resonate and causes the light of the first wavelength to oscillate, a solid-state laser medium that is included in the first resonator and a second resonator causing light of a second wavelength to resonate and causes the light of the second wavelength to oscillate, and a saturable absorber included in the second resonator and emitting the light of the second wavelength; a detector detecting the light of the first wavelength or a drive current of the light emitting element; and an emission timing detecting unit detecting an emission timing of the light of the second wavelength on the basis of a detection result of the light of the first wavelength or the drive current of the light emitting element acquired using the detector.

There is provided a Q-switched semiconductor light-emitting element, including a comb electrode that has at least two or more gain regions and two or more absorption regions, the regions including an active layer and being continuous on a semiconductor substrate, separation regions being provided between the gain regions and the absorption regions, the longest region of the gain regions being located on a rear end surface side; and an optical waveguide that staddles the gain regions, the absorption regions, and the separation regions.