Abstract: Provided is a method of manufacturing an optical integrated device. The method includes forming a lower clad layer on a substrate, forming a plurality of mask patterns arranged in one direction on the lower clad layer, forming a core layer on a portion of the lower clad layer by a selective area growth method using the mask patterns as deposition masks, and forming an upper clad layer on the core layers, wherein the mask patterns have different widths or include mask layers of different materials.

Abstract: Provided is a quarter-wavelength shifted distributed feedback laser diode. The laser diode includes a substrate having a laser diode section and a phase adjustment section, a waveguide layer on the substrate, a clad layer on the waveguide layer, a grating disposed in the clad layer in the laser diode section, an anti-reflection coating disposed on one side walls, of the substrate, the waveguide layer, and the clad layer, adjacent to the laser diode section, and a high reflection coating disposed on the other side walls, of the substrate, the waveguide layer, and the clad layer, adjacent to the phase adjustment section.

Abstract: Provided is a tunable semiconductor laser including an active gain region in which an optical signal is generated according to a modulation signal, a mode control region in which a resonant mode is controlled according to a mode control signal, and a signal chirp of the optical signal is compensated according to a first compensation signal determined based on the modulation signal, and a distributed Bragg reflector (DBR) region in which an oscillation wavelength of the optical signal is determined based on a wavelength selection signal for the optical signal, a second compensation signal for compensating for a thermal chirp of the optical signal on a basis of the modulation signal, and a heater signal provided to a heater electrode.

Abstract: Provided is a quarter-wavelength shifted distributed feedback laser diode. The laser diode includes a substrate having a laser diode section and a phase adjustment section, a waveguide layer on the substrate, a clad layer on the waveguide layer, a grating disposed in the clad layer in the laser diode section, an anti-reflection coating disposed on one side walls, of the substrate, the waveguide layer, and the clad layer, adjacent to the laser diode section, and a high reflection coating disposed on the other side walls, of the substrate, the waveguide layer, and the clad layer, adjacent to the phase adjustment section.

Abstract: Provided is a tunable semiconductor laser including an active gain region in which an optical signal is generated according to a modulation signal, a mode control region in which a resonant mode is controlled according to a mode control signal, and a signal chirp of the optical signal is compensated according to a first compensation signal determined based on the modulation signal, and a distributed Bragg reflector (DBR) region in which an oscillation wavelength of the optical signal is determined based on a wavelength selection signal for the optical signal, a second compensation signal for compensating for a thermal chirp of the optical signal on a basis of the modulation signal, and a heater signal provided to a heater electrode.

Abstract: An optical signal generating apparatus according to an embodiment of the inventive concept includes a first optical intensity modulator for modulating a first optical signal to generate a 2N-level (where N is a positive integer) second optical signal in the form of a binary signal, a first optical amplifier for amplifying the second optical signal to generate a third optical signal, and a second optical intensity modulator for modulating the third optical signal to generate a 2N+1-level fourth optical signal in the form of a binary signal. The optical signal generating apparatus according to an embodiment of the inventive concept may generate a low-cost, high-quality optical signal by using an optical device to generate a multi-level optical signal. Additionally, the optical signal generating apparatus according to an embodiment of the inventive concept may generate a multi-level optical signal by sequentially performing optical modulation and optical amplification operations.

Abstract: An optical signal generating apparatus according to an embodiment of the inventive concept includes a first optical intensity modulator for modulating a first optical signal to generate a 2N-level (where N is a positive integer) second optical signal in the form of a binary signal, a first optical amplifier for amplifying the second optical signal to generate a third optical signal, and a second optical intensity modulator for modulating the third optical signal to generate a 2N+1-level fourth optical signal in the form of a binary signal. The optical signal generating apparatus according to an embodiment of the inventive concept may generate a low-cost, high-quality optical signal by using an optical device to generate a multi-level optical signal. Additionally, the optical signal generating apparatus according to an embodiment of the inventive concept may generate a multi-level optical signal by sequentially performing optical modulation and optical amplification operations.

Abstract: The inventive concept relates to a beating signal monitoring module and a terahertz wave generation device and an optical signal monitoring device that including the beating signal monitoring module. The beating signal monitoring module includes a nonlinear unit generating an optical signal including a FWM light in response to a beating signal generated from a first light and a second light; a filter unit separating the FWM light from the optical signal and outputting the separated FWM light; and a monitoring unit monitoring the beating signal using the separated FWM light. The beating signal monitoring module and a terahertz wave generation device and an optical signal monitoring device that including the beating signal monitoring module can effectively monitor a beating signal being generated by two lasers using a Four Wave Mixing signal.

Abstract: A contactless thickness measuring apparatus is provided which includes an terahertz transmitter configured to receive the first optical path signal from the coupler and to generate a terahertz continuous wave using the first optical signal and an applied bias; an optical delay line configured to delay the second optical path signal output from the coupler; and an terahertz receiver configured to receive the terahertz continuous wave penetrating a sample and to detect an optical current using the terahertz continuous wave and the second optical path signal delayed. A thickness of the sample is a value corresponding to the optical current which phase value becomes a constant regardless of a plurality of measurement frequencies.

Abstract: Provided is a terahertz wave generating/detecting apparatus and a method for manufacturing the same. The terahertz wave generating/detecting apparatus includes; a substrate having an active region and a transmitting region; a lower metal layer extending in a first direction on the active region and the transmitting region of the substrate; a graphene layer disposed on the lower metal layer on the active region; and upper metal layers extending in the first direction on the graphene layer of the active region and the substrate in the transmission region, wherein a terahertz wave is generated or amplified by a surface plasmon polariton that is induced on a boundary surface between the graphene layer and the lower metal layer by beated laser light applied to the graphene layer and the metal layer.

Abstract: A terahertz wave generating module includes a bidirectional light source which provides a first dual-mode beam in a first direction and a second dual-mode beam in a second direction; a forward lens unit which focuses the first dual-mode beam; a photomixer unit which converts the first dual-mode beam focused by the forward lens unit into a terahertz wave; a backward lens unit which focuses the second dual-mode beam; and a light output unit which uses the second dual-mode beam focused by the backward lens unit as a light signal, wherein the bidirectional light source, the forward lens unit, the photomixer unit, the backward lens unit, and the light output unit are integrated in a housing.

Abstract: Provided are a THz-wave generation/detection module and a device including the same, which increase heating efficiency and are miniaturized. The module includes a photomixer chip, a lens, a PCB, and a package. The photomixer chip includes an active layer, an antenna, and a plurality of electrode pads. The lens is disposed on the photomixer chip. The PCB includes a plurality of solder balls connected to the electrode pads, under the photomixer chip. The package surrounds a bottom and side of the PCB, and dissipates heating of the active layer, which is transferred from the electrode pad of the photomixer chip to the PCB, to outside.

Abstract: Provided are a dual mode semiconductor laser and a terahertz wave apparatus using the same. The dual mode semiconductor laser includes a distributed feedback laser structure section including a first diffraction grating on a substrate and a distributed Bragg reflector laser structure section including a second diffraction grating on the substrate. A first wavelength oscillated by the distributed feedback laser structure section and a second wavelength oscillated by the distributed Bragg reflector laser structure section are different from each other, and the distributed feedback laser structure section and the distributed Bragg reflector laser structure section share the same gain medium with each other.

Abstract: An optical device may include first and second lasers generating first and second laser beams; and a photo detector detecting the first and second laser beams. The optical detector comprises a substrate, a first impurity layer on the substrate, an absorption layer on the first impurity layer and a second impurity layer on the absorption layer. The absorption layer generates a terahertz by a beating of the first and second laser beams and has a thickness of less than 0.2 ?m.

Abstract: Provided is a terahertz wave generating/detecting apparatus and a method for manufacturing the same. The terahertz wave generating/detecting apparatus includes; a substrate having an active region and a transmitting region; a lower metal layer extending in a first direction on the active region and the transmitting region of the substrate; a graphene layer disposed on the lower metal layer on the active region; and upper metal layers extending in the first direction on the graphene layer of the active region and the substrate in the transmission region, wherein a terahertz wave is generated or amplified by a surface plasmon polariton that is induced on a boundary surface between the graphene layer and the lower metal layer by beated laser light applied to the graphene layer and the metal layer.

Abstract: The inventive concept relates to a beating signal monitoring module and a terahertz wave generation device and an optical signal monitoring device that including the beating signal monitoring module. The beating signal monitoring module includes a nonlinear unit generating an optical signal including a FWM light in response to a beating signal generated from a first light and a second light; a filter unit separating the FWM light from the optical signal and outputting the separated FWM light; and a monitoring unit monitoring the beating signal using the separated FWM light. The beating signal monitoring module and a terahertz wave generation device and an optical signal monitoring device that including the beating signal monitoring module can effectively monitor a beating signal being generated by two lasers using a Four Wave Mixing signal.

Abstract: A terahertz wave generating module includes a bidirectional light source which provides a first dual-mode beam in a first direction and a second dual-mode beam in a second direction; a forward lens unit which focuses the first dual-mode beam; a photomixer unit which converts the first dual-mode beam focused by the forward lens unit into a terahertz wave; a backward lens unit which focuses the second dual-mode beam; and a light output unit which uses the second dual-mode beam focused by the backward lens unit as a light signal, wherein the bidirectional light source, the forward lens unit, the photomixer unit, the backward lens unit, and the light output unit are integrated in a housing.

Abstract: Disclosed is a terahertz wave generator which includes a first light source outputting a first light having a first frequency; a second light source outputting a second light having a second frequency different from the first frequency; a second harmonic generation unit performing second harmonic conversion on the first and second lights to generate a third light and a fourth light; and a photomixer converting a mixing light of the third and fourth lights into a terahertz wave alternating signal and outputting a terahertz wave.

Abstract: Disclosed is a terahertz wave generator which includes a dual mode semiconductor laser device configured to generate at least two laser lights having different wavelengths and to beat the generated laser lights; and a photo mixer formed on the same chip as the dual mode semiconductor laser device and to generate a continuous terahertz wave when excited by the beat laser light.

Abstract: Disclosed is a terahertz wave generator which includes a first light source outputting a first light having a first frequency; a second light source outputting a second light having a second frequency different from the first frequency; a second harmonic generation unit performing second harmonic conversion on the first and second lights to generate a third light and a fourth light; and a photomixer converting a mixing light of the third and fourth lights into a terahertz wave alternating signal and outputting a terahertz wave.