A core-shell nanowire laser structure comprises a substrate (12), an elongated support element (14) extending from the substrate, the support element having a first diameter, and an elongated body element (16) extending on and/or around the support element, the body element having a second diameter at least two times larger than the first diameter, wherein the body element is spaced apart from the substrate.

A thermal radiation light source includes a laminated body including m quantum layers laminated where m is an integer of 2 or more, including an n-layer and a p-layer sandwiching the quantum layers from both sides in the laminating direction, the n-layer made of an n-type semiconductor and the p-layer made of a p-type semiconductor; a voltage applying unit for the m quantum layers is directly or indirectly connected to the n-layer and p-layer sandwiching each layer applying a voltage for moving to the n-layers or p-layers a charge; a voltage switching unit switches ON/OFF of application of the voltage to the m quantum layers; and a photonic crystal portion disposed in the laminated body or adjacent to the laminated body, so that lights of m wavelengths resonate, the lights of the m wavelengths generated in the m quantum layers corresponding to transition energy between subbands in the quantum layer.

A tunable optical source includes a substrate, a light source disposed on the substrate, and a wavelength selecting element configured to select light of a specific wavelength as output light, from light emitted from the light source, in accordance with a control signal. On the substrate, a wavelength filter including multiple output ports and a photodetector are disposed. The wavelength filter is configured to receive a part of the output light and to output light beams to the respective output ports. The photodetector is configured to receive the light beam output from one of the output ports. The tunable optical source further includes an inspection waveguide connecting to the photodetector at one end, and an inspection light input unit for inputting inspection light provided at the other end of the inspection waveguide.

An optical logic device includes a distributed feedback laser configured to generate a first signal corresponding to distributed feedback laser output signal, the first signal being at a first wavelength. The device further includes a bandpass filter having a center frequency corresponding to the first wavelength. Additionally, the device can include an optical circulator having a first port coupled to a logic device input signal, a second port coupled to the first signal, and a third port coupled to the bandpass filter, wherein when the logic device input signal has a power above a predetermined threshold and there is a wavelength difference between the first wavelength and an input wavelength of the logic device input signal, a suppression of the first signal occurs.

An optical logic device includes a distributed feedback laser configured to generate a first signal corresponding to distributed feedback laser output signal, the first signal being at a first wavelength. The device further includes a bandpass filter having a center frequency corresponding to the first wavelength. Additionally, the device can include an optical circulator having a first port coupled to a logic device input signal, a second port coupled to the first signal, and a third port coupled to the bandpass filter, wherein when the logic device input signal has a power above a predetermined threshold and there is a wavelength difference between the first wavelength and an input wavelength of the logic device input signal, a suppression of the first signal occurs.

Optical systems can emit train(s) of light pulses onto objects to derive a distance between the light source and the object. Achieving meter or centimeter resolution may require very short light pulses. It is not trivial to design a circuit that can generate narrow current pulses for driving a diode that emits the light pulses. An improved driver circuit has a pre-charge path comprising one or more inductive elements and a fire path comprising the diode. Switches in the driver circuit are controlled with predefined states during different intervals to pre-charge current in the one or more inductive elements prior to flowing current through the fire path to pulse the diode.

A photonic crystal device includes a two-dimensional crystal including a gain medium and having a first photonic crystal resonator and a second photonic crystal resonator spaced apart from each other and a graphene layer disposed to cover a portion of the first photonic crystal resonator and not to cover the second photonic crystal resonator.

An optical logic device includes a distributed feedback laser configured to generate a first signal corresponding to distributed feedback laser output signal, the first signal being at a first wavelength. The device further includes a bandpass filter having a center frequency corresponding to the first wavelength. Additionally, the device can include an optical circulator having a first port coupled to a logic device input signal, a second port coupled to the first signal, and a third port coupled to the bandpass filter, wherein when the logic device input signal has a power above a predetermined threshold and there is a wavelength difference between the first wavelength and an input wavelength of the logic device input signal, a suppression of the first signal occurs.

Semiconductor laser device A1 includes semiconductor laser element 4, switching element 5 having gate electrode 52, source electrode 53 and drain electrode 54, and support member 1 having conductive part 3 that forms a conduction path to switching element 5 and semiconductor laser element 4 and supports semiconductor laser element 4 and switching element 5. Conductive part 3 has front surface first section 311 spaced apart from semiconductor laser element 4. Semiconductor laser device A1 includes at least one first wire 71 connected to source electrode 53 of switching element 5 and semiconductor laser element 4 and also at least one second wire 72 connected to source electrode 53 of switching element 5 and front surface first section 311 of conductive part 3. Such an arrangement reduces the inductance component of semiconductor laser device A1.

A core-shell nanowire laser structure comprises a substrate (12), an elongated support element (14) extending from the substrate, the support element having a first diameter, and an elongated body element (16) extending on and/or around the support element, the body element having a second diameter at least two times larger than the first diameter, wherein the body element is spaced apart from the substrate.