Electronics and Telecommunications Research Institute

Byung-Seok Choi

O-Kyun Kwon

Kisoo Kim

Hyun Soo Kim

Dae Kon Oh

Ki-Hong Yoon

Su Hwan Oh

Joong-Seon Choe

Chun Ju Youn

Dong Churl Kim

Jong-Hyun Lee

Oh Kee Kwon

Mi-Ran Park

Kap-Joong Kim

Young-Ho Ko

Jongbae Kim

Minchul Kim

Jong-Tae Moon

Kyongchun Lim

Jin-Soo Kim

Yongsoon Baek

Kwang-Seong Choi

Dong-Hun Lee

Won Seok Han

Duk Jun Kim

Jong-Hoi Kim

Dong-Young Kim

Jong Sool Jeong

Jung-Ho Song

Jong-Deog Kim

Hogyeong Yun

Ho-Gyeong Yun

Jin-Hong Lee

Yong-Sung Eom

Dong Hyo Lee

Ju Hee Baek

Heasin Ko

Dae-Kon Oh

Sung-Ui Hong

A quantum key distribution system using an RFI (reference frame independent) QKD (quantum key distribution) protocol includes a quantum channel transmitter that generates a first quantum signal including quantum information and provides the first quantum signal to an external device through a quantum channel, a first public channel transceiver that generates an optical signal including first additional information related to a QKD operation, and transmits and receives the optical signal through a public channel, a second public channel transceiver that receives the optical signal through the public channel and generates a measurement result by measuring a circular polarization component of the optical signal, and a quantum channel receiver that receives the first quantum signal through the quantum channel, generates a second quantum signal by correcting a polarization distortion of the first quantum signal based on the measurement result, and demodulates the quantum information from the second quantum signal.

Quantum key distribution system and operation method thereof

Provided is a polarization decomposition device. The polarization decomposition device includes a polarization beam splitter configured to split an optical signal into a first polarized light having a first polarization direction and a second polarized light having a second polarization direction different from the first polarized light, a phase shifter configured to delay a phase of the first polarized light, a polarization rotator configured to rotate the second polarized light so that the polarization direction of the second polarized light is changed, and an interference beam splitter configured to allow the first polarized light in which the phase is delayed and the second polarized light in which the polarization direction is rotated to interfere with each other and split them into a third polarized light and a fourth polarized light.

Polarization decomposition device

Disclosed is a quantum key distribution system using an RFI (reference frame independent) QKD (quantum key distribution) protocol, which includes a first signal processing circuit that generates transmission basis information and transmission bit information, a quantum channel transmitter that generates a single photon or coherent light, and modulates the single photon or the coherent light based on the transmission basis information and the transmission bit information to generate a quantum signal, a quantum channel receiver that receives the quantum signal through a quantum channel and detects reception bit information from the quantum signal based on reception basis information, and a second signal processing circuit that generates the reception basis information, transmits the reception basis information to the first signal processing circuit through a public channel, and receives the transmission basis information from the first signal processing circuit through the public channel.

An optical waveguide structure includes a substrate and a core structure disposed on the substrate. The substrate includes a first waveguide region, a second waveguide region, and a transition region between the first waveguide region and the second waveguide region. The core structure includes first core segments arranged in a first direction and a second direction crossing the first direction on the transition region. The core structure includes second core segments arranged in the first direction and the second direction on the second waveguide region. The first direction and the second direction are parallel to a top surface of the substrate.

Optical waveguide structure

Provided herein are a method and apparatus for controlling the wavelength of an external-cavity wavelength-tunable laser. The reflectivity or transmittance characteristics of a wavelength depend on the phase difference between light reflected by a wavelength-tunable filter and parasitic reflective light. Thus, when the temperature of a module and current applied to a phase control electrode and an external reflector are changed, the characteristics are changed in a periodic manner. The present disclosure relates to a wavelength control algorithm of determining combinations of these parameters to set conditions having optimum chirping characteristics at a desired wavelength.

Method and apparatus for controlling external cavity laser

Provided are a high-speed superluminescent diode, a method of manufacturing the same, and a wavelength-tunable external cavity laser including the same. The superluminescent diode includes a substrate having an active region and an optical mode size conversion region, waveguides including an ridge waveguide in the active region and a deep ridge waveguide in the optical mode size conversion region connected to the active waveguide, an electrode disposed on the ridge waveguide; planarizing layers disposed on sides of the ridge waveguide and the deep ridge waveguide on the substrate, and a pad electrically connected to the electrode, the pad being disposed on the planarizing layers outside the active waveguide.

Superluminescent diode, method of manufacturing the same, and wavelength-tunable external cavity laser including the same

Provided is a reflective colorless optical transmitter receiving a carrier signal, which is a continuous wave, and outputting a modulated optical signal. The reflective colorless optical transmitter includes a semiconductor optical amplifier (SOA) amplifying an input optical signal allowing the input optical signal to have a gain, an optical modulator connected to the SOA and outputting a modulated optical signal, a high reflectivity facet reflecting the modulated optical signal from the optical modulator, and a Bragg reflection mirror connected to the high reflectivity facet, the optical modulator, and the SOA in series, wherein a Bragg resonator is formed by the Bragg reflecting mirror and the high reflectivity facet.

Reflective colorless optical transmitter

The present disclosure relates to a tunable laser module including a light gain area unit for outputting an optical signal; an optical distributor for separating the optical signal output from the light gain area unit; two comb reflection units for reflecting a part of optical signals separated by the optical distributor and allow a part of the optical signals to penetrate; two phase units for changing phases of the optical signals penetrating the two comb reflection units; an optical coupler for combining the optical signals of which the phases are changed by the two phase units; and an optical amplifier for amplifying the optical signal combined by the optical coupler, wherein the light gain area unit oscillates a laser by totally reflecting the optical signals reflected by the two comb reflection units.

Tunable laser module

A semiconductor optical device includes a first mode converting core, a light amplification core, a second mode converting core, and a light modulation core disposed in a first mode converting region, a light amplification region, a second mode converting region, and a light modulating region of a semiconductor substrate, respectively, and a current blocking section covering at least sidewalls and a top surface of the light amplification core. The first mode converting core, the light amplification core, the second mode converting core, and the light modulation core are arranged along one direction in the order named, and are connected to each other in butt joints. The current blocking section includes first, second, and third cladding patterns sequentially stacked. The second cladding pattern is doped with dopants of a first conductivity type, and the first and third cladding patterns are doped with dopants of a second conductivity type.

Semiconductor optical devices and methods of fabricating the same

An optical amplifier includes a passive waveguide region and an active waveguide region. The passive waveguide region is configured to receive an incident optical signal and adjust a mode of the optical signal. The active waveguide region is integrated to the passive waveguide region and configured to perform gain modulation on the optical signal received from the passive waveguide region by changing density of carriers in response to a current applied to the active waveguide region. Internal loss of the active waveguide region is adjusted to produce a resonance effect and thereby to increase bandwidth of the active waveguide. Therefore, the optical amplifier can have a wide bandwidth under a low-current condition.

Optical amplifier

Provided is a wavelength-tunable external cavity laser module. The wavelength-tunable external cavity laser module includes: a gain medium generating light; an optical waveguide combined with the gain medium and including a Bragg grating and a thin film heater adjusting a temperature of the Bragg grating; and a high frequency transmission medium delivering a high frequency signal to the gain medium, wherein the high frequency transmission medium controls an operating speed of the light.

Wavelength-tunable external cavity laser module

Provided is a tunable laser module emitting an optical signal having high speed, high power and wideband wavelength tuning. The tunable laser module includes a laser array configured to emit an optical signal having a plurality of different lasing wavelengths, a temperature controller configured to change a temperature of the laser array, and an optical integration device configured to modulate or amplify the optical signal at a side of the laser array opposing the temperature controller.

Provided is a wavelength tunable external cavity laser (laser beam) generating device. The wavelength tunable external cavity laser generating devices includes: an optical amplifier, a comb reflector, and an optical signal processor connected in series on a first substrate; and an external wavelength tunable reflector disposed on a second substrate adjacent to the first substrate and connected to the optical amplifier, wherein the comb reflector includes: a waveguide disposed on the first substrate; a first diffraction grating disposed at one end of the waveguide adjacent to the optical amplifier; and a second diffraction grating disposed at the other end of the waveguide adjacent to the optical signal processor, wherein the optical amplifier, the comb reflector, and the optical signal processor constitute a continuous waveguide.

Wavelength tunable external cavity laser beam generating device

Provided are a semiconductor optical amplifier and an optical signal processing method using the same. The reflective semiconductor optical amplifier includes: an optical signal amplification region operating to allow a downward optical signal incident from the external to obtain a gain; and an optical signal modulation region connected to the optical signal amplification region and generating a modulated optical signal. The downward optical signal is amplified through a cross gain modulation using the modulated optical signal and is outputted as an upward optical signal.

Growing community of inventors

Daejeon, South Korea

Byung-Seok Choi