Abstract: A multi-section semiconductor laser diode is disclosed. The laser diode includes a complex-coupled DFB laser section that includes a complex-coupled grating and an active structure for controlling the intensity of oscillating laser light, to oscillate laser light in a single mode, and an external cavity including a phase control section and an amplifier section, the phase control section having a passive waveguide that controls a phase variation of feedback laser light, the amplification section having an active structure that controls the strength of the feedback laser light. Currents are separately provided to the three sections to generate optical pulses with tuning range of tens of GHz. Applications include the clock recovery in the 3R regeneration of the optical communication.

Abstract: Provided are a photoelectric device using a PN diode and a silicon integrated circuit (IC) including the photoelectric device. The photoelectric device includes: a substrate; and an optical waveguide formed as a PN diode on the substrate, wherein a junction interface of the PN diode is formed in a direction in which light advances; and an electrode applying a reverse voltage to the PN diode, wherein N-type and P-type semiconductors of the PN diode are doped at high concentrations and the doping concentration of the N-type semiconductor is higher than or equal to that of the P-type semiconductor.

Abstract: A full 3R (re-timing, re-shaping, re-amplifying) recovery system is provided. In the full 3R recovery system, a self-pulsating laser diode (SP-LD) and an electroabsorption modulator (EAM) are integrated and disposed on a semiconductor substrate.

Abstract: Provided is an optical device having an edge effect with improved phase shift and propagation loss of light without decreasing the dynamic characteristics of the optical device. The optical device includes a first semiconductor layer which is doped with a first type of conductive impurities, and has a recessed groove in an upper portion thereof; a gate insulating layer covering the groove and a portion of the first semiconductor layer; and a second semiconductor layer which covers an upper surface of the gate insulating layer and is doped with a second type of conductive impurities opposite to the first type of conductive impurities.

Abstract: Provided is a photonics device. The photonics device includes: a substrate including a star coupler region and a transition region; a lower core layer formed on the substrate; and upper core patterns formed on the substrate to define a waveguide. The upper core patterns are disposed on the lower core layer at the transition region, so that the transition region has a multi-layered core structure.

Abstract: Provided are a superluminescent diode with a high optical power and a broad wavelength band, and a method of fabricating the same. The superluminescent diode includes: at least one high optical confinement factor (HOCF) region; and at least one low optical confinement factor (LOCF) region having a lower optical confinement factor than the HOCF region. The method includes obtaining a difference of optical confinement factors in the HOCF region and the LOCF region through a selective area growth method, the selective area growth method using a deposition thicknesses difference of thin layers according to a width difference of openings that expose a substrate.

Abstract: Provided are a hybrid laser diode for single mode operation, and a method for manufacturing the hybrid laser diode. The hybrid laser diode includes a silicon layer, an active pattern disposed on the silicon layer, and a bonding layer disposed between the silicon layer and the active pattern. Here, the bonding layer includes diffraction patterns constituting a Bragg grating.

Abstract: Provided is a hybrid laser diode. The hybrid laser diode includes: a silicon layer constituting a slab waveguide; and a compound semiconductor layer disposed on the silicon layer to constitute a channel waveguide.

Abstract: 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.

Abstract: 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.

Abstract: Provided is an apparatus and method for simultaneous optical wavelength conversion and optical clock signal extraction using semiconductor optical amplifiers (SOAs).

Abstract: Provided are an apparatus for and a method of generating millimeter waves, in which millimeter-wave generation and frequency up-conversion can be achieved at the same time using a single device. The apparatus includes a mode-locking laser diode (LD) which has a distributed feedback (DFB) sector and a gain sector and generates high-frequency optical pulses through a passive mode locking process, a modulator which modulates an external optical signal using an electric signal and injects the modulated optical signal to the mode-locking LD to lock the optical pulses, and a radio frequency (RF) locking signaling unit which injects the electric signal to the modulator.

Abstract: 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.

Abstract: A light source has a structure in which a 3-dB beam splitter is integrated with a Febry-Perot laser diode having a cleaved plane. A first waveguide grating and a first refractive index modifier changing a Bragg wavelength of the first waveguide grating are provided at one branch of the 3-dB beam splitter. A second waveguide grating and a second refractive index modifier changing a Bragg wavelength of the second waveguide grating are provided at another branch of the 3-dB beam splitter.

Abstract: Provided is a signal regenerator for correcting distortion of an optical signal transmitted via an optical fiber in an optical communication system, which includes semiconductor optical amplifiers having different lengths from each other, an asymmetric Mach-Zehnder interferometer that performs 2R (re-amplifying, re-shaping) regeneration, and a delay interferometer with optical waveguides having different lengths from each other, whereby the fabrication is easy and a high-speed signal regeneration is enable.

Abstract: 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.

Abstract: A multi DFB laser diode for generating spontaneous pulses comprises first and second DFB sections each of which has a substrate including a diffraction grating, an active layer formed on the substrate, a clad layer formed on the active layer and including a refraction varying layer, and an electrode formed on the active layer; and a phase tuning section including a substrate, an active layer formed on the substrate, a clad layer formed on the active layer, and an electrode isolated from the electrode of the first and second DFB sections. The refraction varying layer in the active layer of the first DFB section has a refractive index different from that of the refraction varying layer in the active layer of the second DFB section.

Abstract: 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.

Abstract: Disclosed is a high frequency optical pulse source generating stable optical pulses over a wide current range in an optical transmission system to enhance stability and reliability, the high frequency optical pulse source implementing, in one chip, a multi-section distributed feedback (DFB) laser diode with a phase control section arranged between two DFB laser diodes. By controlling the current applied to the electrode of the phase control section while applying currents to the first and second DFB sections, the present invention causes self-mode locking between the compound-cavity modes having similar threshold currents, thereby generating stable tens GHz-level optical pulses. Hence, the present invention generates optical pulses uniformly over a wide current range, thereby enhancing the stability and reliability of the element.

Abstract: A multi DFB laser diode for generating spontaneous pulses comprises first and second DFB sections each of which has a substrate including a diffraction grating, an active layer formed on the substrate, a clad layer formed on the active layer and including a refraction varying layer, and an electrode formed on the active layer; and a phase tuning section including a substrate, an active layer formed on the substrate, a clad layer formed on the active layer, and an electrode isolated from the electrode of the first and second DFB sections. The refraction varying layer in the active layer of the first DFB section has a refractive index different from that of the refraction varying layer in the active layer of the second DFB section.