Abstract: The present invention relates to an image encoding and decoding technique, and more particularly, to an image encoder and decoder using unidirectional prediction. The image encoder includes a dividing unit to divide a macro block into a plurality of sub-blocks, a unidirectional application determining unit to determine whether an identical prediction mode is applied to each of the plurality of sub-blocks, and a prediction mode determining unit to determine a prediction mode with respect to each of the plurality of sub-blocks based on a determined result of the unidirectional application determining unit.

Abstract: Disclosed is an optical sensor, including an external cavity laser configured to output sensing light and reference light; and a photodetector configured to detect a beating signal by an interference of the sensing light and the reference light output from the external cavity laser, in which the external cavity laser includes a reflecting filter including a sensing grating, to which a sensing object is attachable, and a reference grating, which is disposed on the same plane as that of the sensing grating, and outputs sensing light reflected from the sensing grating and reference light reflected from the reference grating. Accordingly, the optical sensor does not require a high-resolution spectroscope and has improved resolution and sensitivity.

Abstract: There is provided a semi-circular resonator using a whispering gallery mode (WGM) and an optical sensor using the same. Accordingly, an active region that is a waveguide of an active layer in which laser oscillation is caused by gains of advancing beams is deeply etched in a semi-circular or semi-ring shape.

Abstract: Disclosed is a self-locked laser system, including: a semiconductor substrate; a laser diode including a first semiconductor part disposed on the semiconductor substrate, and which generates an optical signal; an unidirectional Whispery Gallery Mode (WGM) resonator including a second semiconductor part disposed on the semiconductor substrate; and a structure emitting an optical signal self-locked by the optical signal of the laser diode, in which the laser diode and the resonator are optically coupled on the semiconductor substrate.

Abstract: Disclosed is an optical sensor, including an external cavity laser configured to output sensing light and reference light; and a photodetector configured to detect a beating signal by an interference of the sensing light and the reference light output from the external cavity laser, in which the external cavity laser includes a reflecting filter including a sensing grating, to which a sensing object is attachable, and a reference grating, which is disposed on the same plane as that of the sensing grating, and outputs sensing light reflected from the sensing grating and reference light reflected from the reference grating. Accordingly, the optical sensor does not require a high-resolution spectroscope and has improved resolution and sensitivity.

Abstract: There is provided a semi-circular resonator using a whispering gallery mode (WGM) and an optical sensor using the same. Accordingly, an active region that is a waveguide of an active layer in which laser oscillation is caused by gains of advancing beams is deeply etched in a semi-circular or semi-ring shape.

Abstract: A method of operating a wavelength swept source apparatus includes generating a single mode light, and generating a basic optical comb including light rays having identical frequency differences with adjacent light rays by modulating the generated single mode light. The method further includes generating other optical combs that include the same number of light rays as that of light rays of the optical comb that has a frequency band different from that of the basic optical comb, and is distributed in a frequency band wider than that in which the basic optical comb is distributed, by modulating the light rays of the basic optical comb. The light rays of the basic optical comb and the light rays included in the other optical combs are sequentially emitted according to frequencies of the light rays of the basic optical comb and the light rays included in the other optical combs.

Abstract: A method of operating a wavelength swept source apparatus includes generating a single mode light, and generating a basic optical comb including light rays having identical frequency differences with adjacent light rays by modulating the generated single mode light. The method further includes generating other optical combs that include the same number of light rays as that of light rays of the optical comb that has a frequency band different from that of the basic optical comb, and is distributed in a frequency band wider than that in which the basic optical comb is distributed, by modulating the light rays of the basic optical comb. The light rays of the basic optical comb and the light rays included in the other optical combs are sequentially emitted according to frequencies of the light rays of the basic optical comb and the light rays included in the other optical combs.

Abstract: A variable wavelength diode according to the inventive concept includes a resonator and a plurality of cylindrical lenses. The resonator includes slab waveguides of which resonance lengths are different from each other. The slab waveguides are disposed on a planar light wave circuit (PLC). Thus, the variable wavelength diode realizes a high variation speed and a continuous variation of a beam at the same time.

Abstract: Provided are a wavelength swept source apparatus and a method for controlling thereof. According to the provided apparatus and method, single mode light is generated, a basic optical comb is generated by modulating the generated single mode light, and a plurality of optical combs having different a frequency band from that of the basic optical comb is generated by modulating the plurality of light rays. The plurality of light rays and light rays included in the plurality of optical combs are sequentially emitted according to frequencies of the plurality of light rays and the light rays included in the plurality of optical combs. A value of a control variable is adjusted based on a characteristic of the generated single mode light, the plurality of light rays, the light rays included in the plurality of optical combs, and the emitted light rays.

Abstract: Provided are a wavelength swept source apparatus and a method for operating thereof. According to the provided apparatus and method, single mode light is generated, a basic optical comb including a plurality of light rays having identical frequency differences with adjacent light rays is generated by modulating the generated single mode light, and a plurality of optical combs, that includes same number of light rays as the plurality of light rays, has a different frequency band from that of the basic optical comb, and is distributed in a wider frequency band than that in which the basic optical comb is distributed, is generated by modulating the plurality of light rays. The plurality of light rays and light rays included in the plurality of optical combs are sequentially emitted according to frequencies of the plurality of light rays and the light rays included in the plurality of optical combs.

Abstract: The tunable light source structure proposed in the present invention has an advantage in that a limitation on a typical technology not simultaneously satisfying high-speed tuning and wide range tuning is overcome and thus it is possible to simultaneously satisfy high-speed tuning slower than or equal to several ns and 100 nm-level wide range tuning. Also, a driving method is simpler than that of a typical technology, a stable operation is possible, and it is possible to lower a manufacturing cost of all modules including a driving circuit. In implementing the SLD and the AMZI-FP that are key components of the tunable light source structure of the present invention, an Si or polymer optical waveguide as well as III-group to V-group materials (GaAs, InP and GaSb) may also be employed.

Abstract: Provided is a wavelength tunable light source including a super luminescent diode (SLD) generating lights in a predetermined wavelength band, a voltage generating unit generating first and second voltages, a first filter receiving the first voltage from the voltage generating unit, receiving the lights from the SLD, and transmitting, as second lights, lights corresponding to wavelengths separated by a free spectral range (FSR) from each other among the received lights, a second filter receiving the second voltage from the voltage generating unit, receiving the second lights from the first filter, and transmitting, as a third light, a light corresponding to one wavelength among the separated wavelengths among the received second light, and a reflective mirror disposed at an output end of the second filter and reflects the third light transmitted from the second filter.

Abstract: A variable wavelength diode according to the inventive concept includes a resonator and a plurality of cylindrical lenses. The resonator includes slab waveguides of which resonance lengths are different from each other. The slab waveguides are disposed on a planar light wave circuit (PLC). Thus, the variable wavelength diode realizes a high variation speed and a continuous variation of a beam at the same time.

Abstract: Provided are a reflective semiconductor optical amplifier (R-SOA) and a superluminescent diode (SLD). The R-SOA includes: a substrate; an optical waveguide including a lower clad layer, an active layer independent of the polarization of light, and an upper clad layer sequentially stacked on the substrate, the optical waveguide comprising linear, curved, and tapered waveguide areas; and a current blocking layer formed around the optical waveguide to block a flow of current out of the active layer, wherein the linear and curved waveguide areas have a single buried hetero (BH) structure, and the tapered waveguide area has a dual BH structure.

Abstract: Provided are an optical vision chip (OVC) and an image recognition method using the OVC. The OVC includes: a first display displaying an object image; a second display displaying a standard model image; and an optical sensor optically or electrically coupling the object image and the standard model image respectively displayed on the first and second displays and outputting a difference between the object image and the standard model image as an electrical signal.

Abstract: Provided are a reflective semiconductor optical amplifier (R-SOA) and a superluminescent diode (SLD). The R-SOA includes: a substrate; an optical waveguide including a lower clad layer, an active layer independent of the polarization of light, and an upper clad layer sequentially stacked on the substrate, the optical waveguide comprising linear, curved, and tapered waveguide areas; and a current blocking layer formed around the optical waveguide to block a flow of current out of the active layer, wherein the linear and curved waveguide areas have a single buried hetero (BH) structure, and the tapered waveguide area has a dual BH structure.

Abstract: Provided is a semiconductor laser diode having a waveguide lens. The semiconductor laser diode includes at least one first waveguide having a narrow width, at least one second waveguide having a wide width wider, and at least one waveguide lens having an increasing width from the first waveguide toward the second waveguide and connecting the first waveguide to the second waveguide. Sidewalls of the waveguide lens connecting the first waveguide to the second waveguide may be curved. The second waveguide may be a waveguide providing an optical gain.

Abstract: Provided are a reflective semiconductor optical amplifier (R-SOA) and a superluminescent diode (SLD). The R-SOA includes: a substrate; an optical waveguide including a lower clad layer, an active layer independent of the polarization of light, and an upper clad layer sequentially stacked on the substrate, the optical waveguide comprising linear, curved, and tapered waveguide areas; and a current blocking layer formed around the optical waveguide to block a flow of current out of the active layer, wherein the linear and curved waveguide areas have a single buried hetero (BH) structure, and the tapered waveguide area has a dual BH structure.

Abstract: Provided is a frequency-tunable terahertz light source device. The frequency-tunable terahertz light source device satisfies a Littrow diffraction condition at a wavelength and simultaneously satisfies a Littman-Metcalf diffraction condition at another wavelength using a double diffraction grating having two grating periods. Thus, oscillations simultaneously occur at the two different wavelengths, such that a terahertz wave can be stably generated by beating of the two oscillation wavelengths. In addition, the frequency-tunable terahertz light source device can readily change a frequency up to several terahertz and can be fabricated in a small size.