Patents by Inventor Sung-bock Kim
Sung-bock Kim 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: 7583869Abstract: An electroabsorption (EA) duplexer in which an optical amplifier, a photodetector, and an optical modulator are monolithically integrated to obtain a high radio frequency (RF) gain in radio-over fiber (RoF) link optical transmission technology is provided. The EA duplexer includes a substrate, a separation area, an optical detection/modulation unit, and an optical amplification unit. The separation area includes a first epitaxial layer formed of at least one material layer on the substrate. The first epitaxial layer functions as a first optical waveguide. The optical detection/modulation unit includes a second epitaxial layer formed of at least one material layer on the first epitaxial layer to detect and modulate an optical signal. The second epitaxial layer functions as a second optical waveguide. The optical amplification unit includes the second optical waveguide and a third epitaxial layer formed of at least one material layer on the second epitaxial layer to amplify an optical signal.Type: GrantFiled: June 13, 2006Date of Patent: September 1, 2009Assignee: Electronics and Telecommunications Research InstituteInventors: Young Shik Kang, Je Ha Kim, Sung Bock Kim, Yong Duck Chung, Kwang Seong Choi
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Patent number: 7583868Abstract: 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.Type: GrantFiled: December 6, 2005Date of Patent: September 1, 2009Assignee: Electronics and Telecommunications Research InstituteInventors: Dae Su Yee, Young Ahn Leem, Dong Churl Kim, Kyung Hyun Park, Sung Bock Kim
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Patent number: 7551662Abstract: A distributed feedback (DFB) quantum dot semiconductor laser structure is provided. The DFB quantum dot semi-conductor laser structure includes: a first clad layer formed on a lower electrode; an optical waveguide (WG) formed on the first clad layer; a grating structure layer formed on the optical WG and including a plurality of periodically disposed gratings; a first separate confinement hetero (SCH) layer formed on the grating structure layer; an active layer formed on the first SCH layer and including at least a quantum dot; a second SCH layer formed on the active layer; a second clad layer formed on the second SCH layer; an ohmic layer formed on the second clad layer; and an upper electrode formed on the ohmic layer. Accordingly, an optical WG is disposed on the opposite side of the active layer from the grating structure layer, thereby increasing single optical mode efficiency.Type: GrantFiled: November 24, 2006Date of Patent: June 23, 2009Assignee: Electronics and Telecommunications Research InstituteInventors: Dae Kon Oh, Jin Hong Lee, Jin Soo Kim, Sung Ui Hong, Byung Seok Choi, Hyun Soo Kim, Sung Bock Kim
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Publication number: 20080279243Abstract: A distributed feedback (DFB) quantum dot semiconductor laser structure is provided. The DFB quantum dot semi-conductor laser structure includes: a first clad layer formed on a lower electrode; an optical waveguide (WG) formed on the first clad layer; a grating structure layer formed on the optical WG and including a plurality of periodically disposed gratings; a first separate confinement hetero (SCH) layer formed on the grating structure layer; an active layer formed on the first SCH layer and including at least a quantum dot; a second SCH layer formed on the active layer; a second clad layer formed on the second SCH layer; an ohmic layer formed on the second clad layer; and an upper electrode formed on the ohmic layer. Accordingly, an optical WG is disposed on the opposite side of the active layer from the grating structure layer, thereby increasing single optical mode efficiency.Type: ApplicationFiled: November 24, 2006Publication date: November 13, 2008Applicant: Electronics and Telecommunications Research InstituteInventors: Dae Kon OH, Jin Hong Lee, Jin Soo Kim, Sung Ui Hong, Byung Seok Choi, Hyun Soo Kim, Sung Bock Kim
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Publication number: 20080137694Abstract: 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.Type: ApplicationFiled: October 31, 2007Publication date: June 12, 2008Applicant: ELECTRONICS & TELECOMMUNCIATIONS RESEARCH INSTITUTEInventors: Kyung Hyun PARK, Hyun Sung Ko, Yong Ahn Leem, Min Yong Jeon, Eun Deok Sim, Sung Bock Kim
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Patent number: 7378292Abstract: Provided is a method of fabricating a semiconductor optical device for use in a subscriber or a wavelength division multiplexing (WDM) optical communication system, in which a laser diode (LD) and a semiconductor optical amplifier (SOA) are integrated in a single active layer. The laser diode (LD) and the semiconductor optical amplifier (SOA) are optically connected to each other, and electrically insulated from each other by ion injection, whereby light generated from the LD is amplified by the SOA to provide low oscillation start current and high intensity of output light when current is individually injected through each electrode.Type: GrantFiled: December 2, 2005Date of Patent: May 27, 2008Assignee: Electronics and Telecommunications Research InstituteInventors: Moon Ho Park, Sahng Gi Park, Su Hwan Oh, Yong Soon Baek, Kwang Ryong Oh, Gyung Ock Kim, Sung Bock Kim
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Patent number: 7369595Abstract: A DBR structure in a VCSEL diode, a method of manufacturing the DBR structure, and a VCSEL diode are provided. The DBR structure in the VCSEL diode includes: an InAlGaAs layer having a predetermined refractive index and disposed on an InP substrate; a first InAlAs layer having a lower refractive index than the InAlGaAs layer and disposed on the InAlGaAs layer; an InP layer having a lower refractive index than the InAlGaAs layer and disposed on the first InAlAs layer; and a second InAlAs layer having a lower refractive index than the InAlGaAs layer and disposed on the InP layer. Thus, the DBR structure can reduce optical loss due to type-II band line-up at a junction between the InAlGaAs layer and the InP layer, and thus improve device characteristics.Type: GrantFiled: October 5, 2006Date of Patent: May 6, 2008Assignee: Electronics and Telecommunications Research InstituteInventors: Ki Soo Kim, Won Seok Han, Sung Bock Kim, Dae Kon Oh
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Patent number: 7277222Abstract: Provided is an apparatus and method for simultaneous optical wavelength conversion and optical clock signal extraction using semiconductor optical amplifiers (SOAs).Type: GrantFiled: July 24, 2006Date of Patent: October 2, 2007Assignee: Electronics and Telecommunications Research InstituteInventors: Dong Churl Kim, Min Yong Jeon, Young Ahn Leem, Eun Deok Sim, Kyung Hyun Park, Sung Bock Kim
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Publication number: 20070171515Abstract: An electroabsorption (EA) duplexer in which an optical amplifier, a photodetector, and an optical modulator are monolithically integrated to obtain a high radio frequency (RF) gain in radio-over fiber (RoF) link optical transmission technology is provided. The EA duplexer includes a substrate, a separation area, an optical detection/modulation unit, and an optical amplification unit. The separation area includes a first epitaxial layer formed of at least one material layer on the substrate. The first epitaxial layer functions as a first optical waveguide. The optical detection/modulation unit includes a second epitaxial layer formed of at least one material layer on the first epitaxial layer to detect and modulate an optical signal. The second epitaxial layer functions as a second optical waveguide. The optical amplification unit includes the second optical waveguide and a third epitaxial layer formed of at least one material layer on the second epitaxial layer to amplify an optical signal.Type: ApplicationFiled: June 13, 2006Publication date: July 26, 2007Inventors: Young Shik Kang, Je Ha Kim, Sung Bock Kim, Yong Duck Chung, Kwang Seong Choi
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Patent number: 7248616Abstract: There are provided a bi-directional transceiver module and a method for driving the same. The bi-directional transceiver module includes a 1.3 ?m Distributed Bragg Reflection Laser Diode (DBR LD) including an active layer which performs light-emission in response to a light at 1.3 ?m and a DBR mirror formed near the active layer. The DBR mirror is formed to prevent an upstream signal emerging from the 1.3 ?m DBR LD from being deleted by a PD. A monitoring PD and a PD for detecting an optical signal are integrated and mounted behind the DBR mirror using a butt-joint method. The 1.3 ?m DBR LD, the monitoring PD, and the PD for detecting the optical signal are electrically isolated by insulated areas. To drive the bi-directional transceiver module, a forward bias (+) is applied to a p-electrode formed on the 1.3 ?m DBR LD, a backward bias (?) is applied to p-electrodes formed on the monitoring PD and the PD for detecting the optical signal, and a n-electrode as a common electrode is grounded.Type: GrantFiled: November 14, 2003Date of Patent: July 24, 2007Assignee: Electronics and Telecommunications Research InstituteInventors: Sung Bock Kim, Eundeok Sim, Ki Soo Kim
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Publication number: 20070127535Abstract: A DBR structure in a VCSEL diode, a method of manufacturing the DBR structure, and a VCSEL diode are provided. The DBR structure in the VCSEL diode includes: an InAlGaAs layer having a predetermined refractive index and disposed on an InP substrate; a first InAlAs layer having a lower refractive index than the InAlGaAs layer and disposed on the InAlGaAs layer; an InP layer having a lower refractive index than the InAlGaAs layer and disposed on the first InAlAs layer; and a second InAlAs layer having a lower refractive index than the InAlGaAs layer and disposed on the InP layer. Thus, the DBR structure can reduce optical loss due to type-II band line-up at a junction between the InAlGaAs layer and the InP layer, and thus improve device characteristics.Type: ApplicationFiled: October 5, 2006Publication date: June 7, 2007Inventors: Ki Soo Kim, Wonk Seok Han, Sung Bock Kim, Dae Kon Oh
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Publication number: 20060189016Abstract: Provided is a method of fabricating a semiconductor optical device for use in a subscriber or a wavelength division multiplexing (WDM) optical communication system, in which a laser diode (LD) and a semiconductor optical amplifier (SOA) are integrated in a single active layer. The laser diode (LD) and the semiconductor optical amplifier (SOA) are optically connected to each other, and electrically insulated from each other by ion injection, whereby light generated from the LD is amplified by the SOA to provide low oscillation start current and high intensity of output light when current is individually injected through each electrode.Type: ApplicationFiled: December 2, 2005Publication date: August 24, 2006Inventors: Moon Park, Sahng Gi Park, Su Hwan Oh, Yong Soon Baek, Kwang Ryong Oh, Gyung Ock Kim, Sung Bock Kim
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Patent number: 7012945Abstract: 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.Type: GrantFiled: December 1, 2003Date of Patent: March 14, 2006Assignee: Electronics and Telecommunications Research InstituteInventors: Kyung-Hyun Park, Young-Ahn Leem, Dong-Churl Kim, Dae-Su Yee, Sung-Bock Kim, Yong-Soon Baek
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Patent number: 6985273Abstract: Disclosed is an electro-absorption optical modulator using a semiconductor device. The optical modulator makes use of a change in light absorption caused by displacement of an absorption curve depending on a bias voltage applied to the device. Here, a level of the light absorption depending on the bias voltage is expressed as a transfer function of output light to the applied bias, and the transfer function has a non-linear profile due to a characteristic of a material. Unlike signal modulation of a digital optical communication system, an analog optical transmission system can be subjected to deterioration in performance, because the non-linear characteristic of the transfer function for the optical modulator generates signal distortion when an electrical signal is converted into an optical signal. The typical optical modulator has an absorption layer constituted of quantum wells having the same width.Type: GrantFiled: December 23, 2003Date of Patent: January 10, 2006Assignee: Electronics and Telecommunications Research InstituteInventors: Young Shik Kang, Je Ha Kim, Ji Youn Lim, Sung Bock Kim
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Patent number: 6928098Abstract: 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.Type: GrantFiled: July 31, 2003Date of Patent: August 9, 2005Assignee: Electronics and Telecommunications Research InstituteInventors: Dong-Churl Kim, Young-Ahn Leem, Dae-Su Yee, Kyung-Hyun Pakr, Sung-Bock Kim, Yong-Soon Baek, Eun-Deok Sim
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Patent number: 6885804Abstract: A semiconductor optical device with a differential grating formed by a holography method and a method for manufacturing the same are provided. The provided semiconductor optical device includes an n-type InP substrate, a stack structure on the InP substrate having a waveguide and active layers, a first grating formed under the stack structure and on the InP substrate, and a second grating formed on the stack structure. The provided method for manufacturing the semiconductor optical device forms a first grating on the n-type InP substrate and under the active layer, and forms a second grating on the active layer. The first and second gratings are formed by the holography method.Type: GrantFiled: October 25, 2002Date of Patent: April 26, 2005Assignee: Electronics and Telecommunications Research InstituteInventors: Kyung-hyun Park, Jung-ho Song, Sung-bock Kim, Kwang-ryong Oh
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Publication number: 20040125851Abstract: 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.Type: ApplicationFiled: December 1, 2003Publication date: July 1, 2004Inventors: Kyung-Hyun Park, Dae-Su Yee, Dong-Churl Kim, Young-Ahn Leem, Sung-Bock Kim
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Publication number: 20040125845Abstract: 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.Type: ApplicationFiled: December 1, 2003Publication date: July 1, 2004Inventors: Kyung-Hyun Park, Young-Ahn Leem, Dong-Churl Kim, Dae-Su Yee, Sung-Bock Kim, Yong-Soon Baek
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Publication number: 20040114656Abstract: 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.Type: ApplicationFiled: July 31, 2003Publication date: June 17, 2004Inventors: Dong-Churl Kim, Young-Ahn Leem, Dae-Su Yee, Kyung-Hyun Park, Sung-Bock Kim, Yong-Soon Baek, Eun-Deok Sim
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Publication number: 20040105680Abstract: There are provided a bi-directional transceiver module and a method for driving the same. The bi-directional transceiver module includes a 1.3 &mgr;m Distributed Bragg Reflection Laser Diode (DBR LD) including an active layer which performs light-emission in response to a light at 1.3 &mgr;m and a DBR mirror formed near the active layer. The DBR mirror is formed to prevent an upstream signal emerging from the 1.3 &mgr;m DBR LD from being deleted by a PD. A monitoring PD and a PD for detecting an optical signal are integrated and mounted behind the DBR mirror using a butt-joint method. The 1.3 &mgr;m DBR LD, the monitoring PD, and the PD for detecting the optical signal are electrically isolated by insulated areas. To drive the bi-directional transceiver module, a forward bias (+) is applied to a p-electrode formed on the 1.Type: ApplicationFiled: November 14, 2003Publication date: June 3, 2004Inventors: Sung Bock Kim, Eundeok Sim, Ki Soo Kim