Electronics and Telecommunications Research Institute

Eun Deok Sim

Kyung Hyun Park

Young Ahn Leem

Dong Churl Kim

Hyun-Soo Kim

Hyun Soo Kim

Oh Kee Kwon

Jeong Woo Park

Sung Bock Kim

Min Yong Jeon

Kang Ho Kim

Kwang Ryong Oh

Yong Soon Baek

Jong Hoi Kim

Hyun Sung Ko

Dae Su Yee

Dong Hun Lee

Ki Soo Kim

Moon Ho Park

Jae Sik Sim

Sahng Gi Park

Provided is a self-pulsating laser diode including: a distributed feedback (DFB) section serving as a reflector; a gain section connected to the DFB section and having an as-cleaved facet at one end; a phase control section interposed between the DFB section and the gain section; and an external radio frequency (RF) input portion applying an external RF signal to at least one of the DFB section and the gain section.

Self-pulsating laser diode

Provided are a laser diode generating passive mode locking that does not contain non-linear sector of an SA, and a method of creating an optical pulse using the same diode. The laser diode includes a DFB sector serving as a reflector and a gain sector. The gain sector is connected to the DFB sector and includes an as-cleaved facet formed at the end of the gain sector. When a current less than a threshold current is applied to the DFB sector to allow the DFB sector to operate as a reflector, passive mode locking occurs swiftly and therefore a sector of the SA is not required, which makes manufacturing simple. Also, it is possible to effectively extend a frequency variable region compared to using of the SA.

Laser diode generating passive mode and method of creating optical pulse using the same diode

The 3R regeneration system for a retiming, reshaping, and reamplifying an optical signal includes: first and second input ports in which a connected optical signal is input; an interferometer including first and second branches formed on a substrate, split at a common input node, combined at a common output node, semiconductor optical amplifiers in each of the first and second branches, the first branch being connected to the first input port, and the common input node being connected to the second input port; a self-pulsating laser diode monolithically integrated with the interferometer between one of the first input port and the first branch, and the second input port and the common input node on the substrate, receiving an optical signal, and outputting the optical signal regenerated by optical injection locking; and an output port connected to the common output node.

Optical signal retiming, reshaping, and reamplifying (3R) regeneration system having monolithically integrated Mach Zehnder interferometer and self-pulsating laser diode

Provided is a signal processor for converting a signal that converts a return to zero (RZ) signal into a non-return to zero (NRZ) signal, in which two 2R (re-amplifying, re-shaping) regenerators are connected in parallel between an input waveguide and an output waveguide with different lengths from each other. The 2R regenerator includes: two semiconductor optical amplifiers having different lengths from each other; and phase control means connected to a short semiconductor optical amplifier. The RZ signal input by a length difference of the waveguide is delayed by a time difference of a half of one bit so that the 2R regenerated NRZ signal can be obtained.

Signal processor for converting signal

A waveguide PIN photodiode is provided. The waveguide PIN photodiode includes a lower light guide layer, a light absorption layer, an upper light guide layer, and a cladding layer. The lower light guide is formed on a substrate, and the light absorption layer is formed on the lower light guide layer. The upper light guide layer is formed on the light absorption layer, and the cladding layer is formed on the upper light guide layer. The lower light guide layer, the light absorption layer, and the upper light guide layer constitute a core layer, which is an optical waveguide, and graded index distribution is symmetrically formed in a depth direction, centering around the light absorption layer having a highest refractive index.

Waveguide PIN photodiode having graded index distribution centering around optical absorption layer

The present invention relates to a semiconductor based parabolic waveguide-type collimating lens and a monolithically integrated type tunable external cavity laser diode light source. The monolithically integrated type tunable external cavity laser diode light source includes a gain medium for generating a gain of an optical signal, a collimating lens for correcting an divergent light beam to a parallel light beam, a passive waveguide through which the parallel light beam travels, an optical deflector to change a traveling direction of the parallel light beam changing a refractive index of medium on a traveling path of the parallel light beam traveling through the slab waveguide in response to an external electric signal and a diffraction grating to diffract the parallel light beam passing through the optical deflector, wherein these are integrate into one substrate made of an InP-based semiconductor as well as a material such as a GaAs-based semiconductor, a Si-based semiconductor, LiNbO-based semiconductor or the like.

Parabolic waveguide-type collimating lens with tunable external cavity laser diode provided with the same

Provided is an apparatus and method for simultaneous optical wavelength conversion and optical clock signal extraction using semiconductor optical amplifiers (SOAs). The apparatus includes: a wavelength converter receiving a pump beam having input information and a probe beam having a different wavelength from the pump beam, and outputting the pump beam with an overshoot shifted to a red wavelength and an undershoot shifted to a blue wavelength due to non-linear characteristics and self-phase modulation of semiconductor optical amplifiers (SOAs) and the probe beam delivered the input information from the pump beam; an optical divider dividing output paths of the probe beam to which the input information has been delivered and the pump beam having the overshoot and the undershoot; a converted-wavelength extractor filtering the probe beam received from the optical divider; and a clock data regenerator obtaining a pseudo return-to-zero (PRZ) signal from the pump beam received from the optical divider and extracting a clock signal from the PRZ signal. The apparatus and method can simultaneously perform wavelength conversion and optical clock signal extraction on an NRZ signal using an optical method, without converting the NRZ signal into an electrical signal.

Apparatus and method for wavelength conversion and clock signal extraction using semiconductor optical amplifiers

Provided is a waveguide photodetector including: a first clad layer disposed on a substrate; a core layer disposed on the first clad layer and for absorbing predetermined light; a second clad layer disposed on the core layer; and at least one subsidiary layer inserted in the first clad layer and the second clad layer. In this structure, the photodetector has about the same spot size as that of an optical fiber or planar lightwave circuit (PLC), so that incident light can be absorbed without loss, and the photodetector can more efficiently combine with the optical fiber or PLC and operate even at high power.

Waveguide photodetector

Parabolic waveguide-type collimating lens and tunable external cavity laser diode provided with the same

Provided is a wavelength tunable light source that can electrically tune wavelengths by monolithically integrating an optical amplifier, a beam steering unit, and a concave diffraction grating on a single substrate. A beam is deflected by the beam steering unit when an electrical signal is applied to two electrodes installed in the beam steering unit to be incident on the diffraction grating, and then diffracted by the diffraction grating according to the incidence angle such that part of the beam with a specific wavelength is reflected, thereby achieving wavelength tuning. Since the wavelength tuning is achieved electrically, the wavelength tunable light source is structurally stable and has a rapid wavelength tuning rate.

Wavelength tunable light source integrated with optical amplifier, beam steering unit, and concave diffraction grating

Provided is a method for manufacturing a planar buried semiconductor optical amplifier in which a spot size converter with a double-core structure is integrated, comprising the steps of: after growing a lower cladding layer, a lower waveguide layer and an upper cladding layer on a substrate, patterning a portion of thickness of the lower cladding layer, the lower waveguide layer and the upper cladding layer through an etching process using a dielectric layer pattern to form a lower waveguide; growing a planarization layer on the etched portions of the lower cladding layer, the lower waveguide layer and the upper cladding layer to smooth a surface; after removing the dielectric layer pattern, growing a space layer, an upper waveguide layer and a first cladding layer on the overall upper surface; patterning the first cladding layer, the upper waveguide layer and the space layer through the etching process using the dielectric layer pattern to form an upper waveguide having a horizontal taper area; after growing a first current blocking layer on the etched portions of the first cladding layer, the upper waveguide layer and the space layer of the upper waveguide, growing a second current blocking layer on the exposed portion of the first current block layer excluding the dielectric layer pattern; and after removing the dielectric layer pattern, forming a second cladding layer on the overall upper surface, and forming an electrode on the second cladding layer and the substrate, respectively.

Growing community of inventors

Daejeon, South Korea

Eun Deok Sim