Patents by Inventor Tae Ahn
Tae Ahn has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 6538804Abstract: A planar waveguide-type optical amplifier switch is disclosed. The switch is developed with the purpose of solving the problems that the conventional waveguide-type optical switch, which has been being used in the optical communication technique, has an optical loss and thereby requires an external optical amplifier which makes the whole devices not suitable for forming an integrated compact device. The disclosed switch performs switching function from the refractive index change in the optical waveguides induced by electrical or optical controls as well as amplifying function of the optical signal, when it passes through the waveguides, from use of optical waveguides formed of a fluorescence emitting material with an optical pumping and a wavelength division multiplexing (WDM) optical waveguide-type coupler.Type: GrantFiled: November 4, 1999Date of Patent: March 25, 2003Assignee: Electronics and Telecommunications Research InstituteInventors: Kyong Hon Kim, Yong Gyu Choi, Hak Kyu Lee, Min Yong Jeon, Joon Tae Ahn, Dong Sung Lim, Ho Young Kim, Do Il Chang
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Patent number: 6528361Abstract: The present invention relates to a process for preparing a polycrystalline silicon thin film comprising a step of microwave annealing and crystallization of an amorphous thin film of silicon semiconductor, silicon semiconductor added with impurities, IV family semiconductor comprising Si alloy such as Si1−xGex, III-V family and II-VI family semiconductor. The process for preparing polycrystalline silicon thin film of the present invention comprises the steps of: immersing a washed substrate into a deposition equipment and heating the substrate; depositing an amorphous or microcrystalline silicon thin film on the substrate; and, annealing the deposited thin film employing microwave for crystallization.Type: GrantFiled: August 14, 2000Date of Patent: March 4, 2003Assignee: Korea Advanced Institute of Science and TechnologyInventors: Byung-Tae Ahn, Do-Kyung Kim, Jong-Hee Kim, Jeong-No Lee, Yoon-Chang Kim
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Publication number: 20030035204Abstract: The present invention utilizes an amplified spontaneous emission (ASE) as a pumping source, thereby enhancing an amplification capability of a two-stage L-band EDFA. The two-stage L-band EDFA of the present invention includes a first amplifier and a second amplifier. The first amplifier is designed as a reflective amplifier, thereby re-amplifying a forward ASE by means of a gain medium. The first amplifier has a pumping LD, a WDM coupler, a first EDF and a Faraday rotating mirror. The second amplifier plays a role in amplifying an optical signal by utilizing the re-amplified forward ASE and the backward ASE as the pumping light. Here, the forward ASE and the backward ASE are transmitted to the second amplifier through an optical circulator. The second amplifier has a second EDF and an optical isolator.Type: ApplicationFiled: December 6, 2001Publication date: February 20, 2003Inventors: Joon Tae Ahn, Min Yong Jeon, Kyong Hon Kim
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Publication number: 20030024274Abstract: The present invention relates to a method of manufacturing a waveguide using an ion exchange process. The present invention controls the refractive index and the thickness of a surface layer on a glass substrate using an ion exchange process, forms the waveguide pattern on the surface layer by means of photolithography and etching process and coats with materials having the refractive index same to or lower than that of the glass substrate to form a cladding layer. Accordingly, the present invention can manufacture a planar waveguide, which is excellent in dimension control and reproducibility and has a sharp step wall.Type: ApplicationFiled: December 26, 2001Publication date: February 6, 2003Inventors: Doo Hee Cho, Joon Tae Ahn, Min Yong Jeon, Kyong Hon Kim
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Publication number: 20020159688Abstract: A high-speed wavelength channel selector has properties of relatively easy manufacturing and easy extension to multi-channel integration, and a high-speed space and wavelength multiplexed channel selector uses the high-speed wavelength channel selector. The high-speed wavelength channel selector is integrated with electro-optic waveguide switches of non-crystalline materials, such as electro-optic polymers or glasses, in the middle of a pair of wavelength multiplexer and demultiplexer and the high-speed space and wavelength multiplexed channel selector has the photonic integrated circuit-type composition of a space multiplexed channel selector containing M electro-optic waveguide switches and an M×1 channel combiner, the high-speed wavelength channel selector, optical amplifier and a high-speed wavelength converter.Type: ApplicationFiled: April 15, 2002Publication date: October 31, 2002Inventors: Kyong Hon Kim, Joon Tae Ahn, Yong Gyu Choi, Doo-Hee Cho
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Publication number: 20020150329Abstract: The present invention relates to a multi-channel wavelength division multiplexer/demultiplexer capable of efficiently coupling or separating wavelength multiplexed optical signals. The multi-channel wavelength division multiplexer/demultiplexer according to the present invention comprises a band splitting means for splitting the band of wavelength multiplexed optical signals (&lgr;1˜&lgr;n) into M bands, a demultiplexing means for separating each band split by the band splitting means into a plurality of single wavelength channels, and a multiplexing means for coupling the single wavelength channels separated by the demultiplexing means. Therefore, the present invention can significantly increase the number of available wavelength channels while minimizing optical loss of wavelength channels.Type: ApplicationFiled: August 29, 2001Publication date: October 17, 2002Inventors: Joon Tae Ahn, Kyong Hon Kim, Min Yong Jeon, Doo Hee Cho, Myung Hyun Lee
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Publication number: 20020000667Abstract: A method of manufacturing an insulating film in a semiconductor device is disclosed. The method comprises the steps of forming a SOD film on the entire structure to fill any distance between conductive layer patterns and after performing a curing process, forming a hard mask film on the SOD film, wherein the silicon oxide film is deposited by plasma deposition method using SiH4 and N2O as a reaction gas at a low-temperature and at a low-pressure and wherein in a stabilization step, the supply amount of SiH4 is greater than that of N2O and in a deposition step, the supply amount of N2O is greater than that of SiH4.Type: ApplicationFiled: June 13, 2001Publication date: January 3, 2002Inventors: Sang Tae Ahn, Jung Gyu Song
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Patent number: 6266458Abstract: The present invention provides a tunable optical filtering system using fiber-optic polarimetric interferometer. The tunable optical filtering system using fiber-optic polarimetric interferometer in accordance with the present invention comprises a stabilization light source, a first polarization beam splitter, a first optical fiber node, a number of polarization maintaining optical fibers, a phase modulator, a stabilization electronics, a second optical fiber node, a second polarization beam splitter, and two wavelength division optical multiplexers. The stabilization light source supplies stabilization light. The first polarization beam splitter polarizes the stabilization light and the input light to be filtered and generates polarized light. The first optical fiber node connects the output of the first polarization beam splitter with polarization maintaining fibers with the angle of 45 degree between their birefringent axes and splits the polarized light.Type: GrantFiled: October 13, 1999Date of Patent: July 24, 2001Assignee: Electronics and Telecommunications Research InstituteInventors: Joon Tae Ahn, Hak Kyu Lee, Min-Yong Jeon, Dong Sung Lim, Kyong-Hon Kim
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Patent number: 6266145Abstract: An apparatus for measurement of an optical pulse shape intended to measure the temporal waveform of an ultrashort single optical pulse is disclosed. The present invention comprises a linearly chirped supercontinuum light source that is synchronized with an optical pulse to be measured; a nonlinear optical interferometer to transform the temporal waveform of an incident optical pulse into a spectrum using an incident light from said supercontinuum light source; and an optical spectrum analyzer to measure the wavelength of the light passing through the nonlinear interferometer so that it can measure the temporal waveform of a single optical pulse. The present invention employs the method that transforms the temporal waveform of an incident optical pulse into a spectrum and measures the wavelength using a linearly chirped supercontinuum light source, a nonlinear optical interferometer, and an optical spectrum analyzer.Type: GrantFiled: November 16, 1999Date of Patent: July 24, 2001Assignee: Electronics and Telecommunications Research InstituteInventors: Hak Kyu Lee, Dong Sung Lim, Min Yong Jeon, Joon Tae Ahn, Kyong Hon Kim
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Patent number: 6256432Abstract: The present invention provides a demultiplexer for generating a constant four-wave-mixing beam without regard to an input polarization state using a dispersion-shifted fiber that is a nonlinear material with high refractive index. A number of parts in conventional demultiplexer implementations, which are sensitive to input polarization state has been replaced with optical fibers of high polarization mode dispersion.Type: GrantFiled: August 25, 1999Date of Patent: July 3, 2001Assignee: Electronics and Telecommunications Research InstituteInventors: Min-Yong Jeon, Hak Kyu Lee, Dong Sung Lim, Joon-Tae Ahn, Kyoung-Hon Kim
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Patent number: 6160393Abstract: A bandgap voltage reference circuit according to the present invention generates a constant reference voltage and is not affected by variations in a power supply voltage and in a manufacturing process. In the bandgap voltage reference circuit, a constant voltage supply unit supplies a constant voltage, a first current mirror mirrors a first current flowing through the constant voltage supply unit to generate a second current, and a second current mirror controlled by the constant voltage from the constant voltage supply unit mirrors the second current to generate a third current and outputs the third current to an output node. A voltage reference unit is connected to the output node to provide a reference voltage to the output node. The voltage reference unit includes at least one PMOS transistor and at least one NMOS transistor which are connected to each other in series or in parallel.Type: GrantFiled: October 14, 1999Date of Patent: December 12, 2000Assignee: Samsung Electronics Co., Ltd.Inventors: Sung-tae Ahn, Yong-jin Jeon
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Patent number: 6160627Abstract: An optical fiber Mach-Zehnder interferometer optical filter is disclosed.Type: GrantFiled: May 21, 1999Date of Patent: December 12, 2000Assignee: Electronics and Telecommunications Research InstituteInventors: Joon Tae Ahn, Hak Kyu Lee, Min Yong Jeon, Dong Sung Lim, Kyong Hon Kim, El Hang Lee
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Patent number: 6133241Abstract: A method for increasing the plasma high density lipoprotein(HDL) level in a mammal comprises administering a bioflavonoid of formula(I) or plant extract containing same thereto: ##STR1## wherein, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5.sub.7 R.sup.6, R.sup.7, R.sup.8 and R.sup.9 are each independently hydrogen; a hydroxy group; a C.sub.1-9 alkoxy group optionally substituted with one or more substituents selected from the group consisting of a hydroxy, C.sub.1-5 alkoxy, aryloxy, and phenyl group substituted with 1 to 3 substituents selected from the group consisting of a hydroxy, alkoxy, aryloxy, halogen, nitro and amido group; a C.sub.5-9 cycloalkyloxy group substituted with 1 to 3 substituents selected from the group consisting of a hydroxy, alkoxy, aryloxy, halogen, nitro and amido group; a C.sub.5-9 cycloalkylcarbonyloxy group substituted with 1 to 3 substituents selected from the group consisting of a hydroxy, alkoxy, aryloxy, halogen, nitro and amido group; a C.sub.2-10 or C.sub.Type: GrantFiled: October 22, 1998Date of Patent: October 17, 2000Assignee: Korea Institute of Science & TechnologyInventors: Song-Hae Bok, Tae-Sook Jeong, Surk-Sik Moon, Yong-Kook Kwon, Byung-Hwa Hyun, Chul-Ho Lee, Yang-Kyu Choi, Myung-Sook Choi, Sung-Gyu Kim, Og-Sung Moon, Sae-Bom Lee, Eun-Sook Lee, Byung-Tae Ahn
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Patent number: 6101027Abstract: The present invention discloses an all-optical wavelength converter using a semiconductor optical amplifier and a polarization interferometer. The all-optical wavelength converter using a semiconductor optical amplifier and a polarization interferometer including a wavelength converter which modulates a probe light into a inverting waveform to a signal light and outputs the modulated light by using cross gain modulation, a phenomenon that occurs while the signal light and the probe light pass together through an optical splitter/combiner, a semiconductor optical amplifier and a filter at the same time, a polarization interferometer which makes the probe light outputted from the wavelength converter and having the inverting waveform to the signal light undergo a double-refraction so that a predetermined time split occurs on it and provides a non-inverting wavelength conversion and suppresses the slow XGM components in the converted outputs due to the slow carrier recombination time.Type: GrantFiled: September 2, 1998Date of Patent: August 8, 2000Assignee: Electronics and Telecommunications Research InstituteInventors: Hak Kyu Lee, Kyong Hon Kim, Joon Tae Ahn, Min Yong Jeon, Dong Sung Lim, Ho Young Kim
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Patent number: 6096364Abstract: A method for lowering the blood glucose level in a mammal comprises administering an effective amount of a hesperetin or naringenin bioflavonoid.Type: GrantFiled: October 22, 1998Date of Patent: August 1, 2000Assignee: Korea Institute of Science & TechnologyInventors: Song-Hae Bok, Tae-Sook Jeong, Ki-Hwan Bae, Yong-Bok Park, Myung-Sook Choi, Surk-Sik Moon, Yong-Kook Kwon, Eun-Sook Lee, Byung-Hwa Hyun, Yang-Kyu Choi, Chul-Ho Lee, Byung-Tae Ahn, Sae-Bom Lee
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Patent number: 6097861Abstract: An improved multi-wavelength channel transmission filter, by which it is possible to selectively and simultaneously separate multiple wavelength channel signals without any optical time delays among, different wavelength channels, includes one optical circulator with four terminal ports, one polarization beam splitter (PBS), one half-wave plate, and a number of Brag, gratings formed in an optical waveguide for reflection of multi-wavelength channels by combining the wavelength characteristic of each Bragg grating which is determined in accordance with the grating structure.Type: GrantFiled: July 9, 1998Date of Patent: August 1, 2000Assignee: Electronics and Telecommunications Research InstituteInventors: Kyong Hon Kim, Hak Kyu Lee, Joon Tae Ahn, El Hang Lee
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Patent number: 6055345Abstract: The present invention provides a multi-wavelength channel transmission-type optical filter that is capable of more narrowing the bandwidth of transmission wavelength in a transmission type optical filter using Mach-Zehnder interferometer. The multi-wavelength channel transmission-type optical filter including a first optical fiber coupler for dividing a broadband light source into two lights, an optical fiber length and optical fiber length controlling unit for controlling the gap of transmission wavelength in which each receives as inputs the above lights divided by the first optical fiber coupler, a second optical fiber coupler for outputting each of the above lights, which are passed through the optical fiber length controlling unit and the optical fiber length, and an optical isolator for narrowing the width of transmission wavelength by connecting the two outputs of the second optical fiber coupler, thereby improving a wavelength selecting characteristics.Type: GrantFiled: August 11, 1998Date of Patent: April 25, 2000Assignee: Electronics and Telecommunications Research InstituteInventors: Joon Tae Ahn, Hak Kyu Lee, Kyong Hon Kim, El Hang Lee
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Patent number: 6008107Abstract: An integrated circuit device is fabricated upon a semi-conductor wafer by first forming a stop layer upon the surface of the wafer. Holes are formed through the stop layer and wells are formed in the semiconductor material of the semiconductor wafer below the openings. A dielectric layer is formed over the surface of the device substantially filling the wells and covering the stop layer. The dielectric layer is then planarized to substantially the level of the stop layer. A PAD oxide layer is provided between the stop layer and the surface of the semiconductor device. Conventional thin film oxidation of the wells and implants into the side walls of the wells are performed. An abrasive mechanical polisher is used to perform the planarization wherein the mechanical polisher is provided with the self-stopping feature when it encounters the stop layer.Type: GrantFiled: July 23, 1997Date of Patent: December 28, 1999Assignee: National Semiconductor CorporationInventors: John M. Pierce, Sung Tae Ahn
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Patent number: 5990514Abstract: A nonvolatile semiconductor memory device includes a plurality of floating gate type memory cell transistors having control gates. Word lines are integrally formed with the control gates, and boosting lines are self-aligned with the word lines. During programming, a first voltage is applied to a selected word line, and then a second voltage is applied to the boosting line over the selected word line. The voltage on the selected word line is then increased by capacitive coupling of the second voltage thereon, thereby programming at least one selected memory cell transistor. Therefore, a voltage lower than a program voltage is used on a selected word line, thereby reducing chip area and enhancing programming speed.Type: GrantFiled: October 2, 1998Date of Patent: November 23, 1999Assignee: Samsung Electronics Co., Ltd.Inventors: Jung-Dal Choi, Sung-Tae Ahn
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Patent number: 5898716Abstract: A laser structure for obtaining an optical pulse of a very short duration by using the benefit of a passive mode locking and for improving a repetition rate of an output optical pulse was described. In general, a passively mode-locked laser generates a short optical pulse than a active mode locked laser does, while it has difficulties in increasing the repetition rate of the output optical pulse because the repetition rate of the passively mode-locked laser is determined by the length of the resonator. In accordance with the present invention, a delayed optical path is added to the linear loop of a conventional figure-8 optical fiber laser. The propagation time difference .DELTA.T between the delayed optical path and undelayed short optical path is adjusted to a divisor of the round trip time, T, of the original resonator by properly adjusting the length of the delayed optical path. Thus, the repetition rate of the output optical pulse of the mode locked laser can be increased from 1/T Hz to 1/.DELTA.T Hz.Type: GrantFiled: September 22, 1997Date of Patent: April 27, 1999Assignee: Electronics and Telecommunications Research InstituteInventors: Joon Tae Ahn, Hack Kyu Lee, Kyong Hon Kim