Chang-Hee Lee

Samsung (South Korea)

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Co-Authors

Sil‐Gu Mun

Electronics and Telecommunications Research Institute

Joon-Young Kim

Korea Advanced Institute of Science and Technology

Jung-Hyung Moon

Korea Advanced Institute of Science and Technology

Sang-Hwa Yoo

Konyang University

Ki-Man Choi

Korea Telecom (South Korea)

Sang‐Rok Moon

Electronics and Telecommunications Research Institute

Hoon-Keun Lee

Korea Advanced Institute of Science and Technology

Myeonggyun Kye

Samsung (South Korea)

Jin-Serk Baik

Korea Advanced Institute of Science and Technology

Sang-Mook Lee

Seoul National University

Cooperative Institutions

Korea Advanced Institute of Science and Technology

Samsung (South Korea)

Electronics and Telecommunications Research Institute

Seoul National University

Korea University

Hanyang University

Korea Institute of Science and Technology

Sungkyunkwan University

Korea Photonics Technology Institute

Yonsei University

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A new burst-mode optical receiver with two preamplifers having different bandwidths

Chang-Hee Lee Y. C. Chung

Burst mode (computing)

Mode (computer interface)

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A perfect secure optical-network with an anti-correlated noise

Optics Communications (2020)

Il-Pyeong Hwang Chang-Hee Lee

We propose a perfect secrecy optical communication with an anti-correlated noise between wavelength-division-multiplexed (WDM) channels. The anti-correlated noise carries confidential information. By sending the different WDM channels to different communication paths in optical communication networks (wired and/or wireless), the achievable signal-to-noise ratio for eavesdroppers can be restricted to much less than that of a target receiver. We demonstrate a perfect secrecy optical network with a three-channel anti-correlated noise generated by using a Fabry–Perot laser diode and a broadband light source. The secure data-rate of 3.95-Gb/s was achieved against an eavesdropper on a single path. We also investigate a secrecy capacity as a function of the number of eavesdropped paths. Finally, security enhancement methods for the proposed system are introduced.

10.1016/j.optcom.2020.125649

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Citations (1)

All-optical clock recovery in dark pulse mode using a modelocked erbium-doped fiber laser

Chang-Hee Lee

Erbium

Source

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Searching and Autoalignment Method for Indoor Free-space Optical Communication

Korean Journal of Optics and Photonics (2019)

Kwanyong Lee Seung-Rae Cho Chang-Hee Lee

Free-Space Optical Communication

Free space

10.3807/kjop.2019.30.6.230

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DWDM-PON at 25 GHz channel spacing based on ASE injection seeding

Optics Express (2012)

Joon-Young Kim Sang‐Rok Moon Sang-Hwa Yoo Chang-Hee Lee

We demonstrate a 25 GHz-channel-spaced DWDM-PON based on ASE injection seeding. A 60 km transmission at 1.25 Gb/s per channel is available with a 2nd generation FEC. The major limiting factor is the optical back reflection induced penalty. Thus a high gain reflective modulator and/or relocation of the seed light increase the transmission length. We demonstrated 90 km transmission with relocated seed light to remote node.

Amplified spontaneous emission

Channel spacing

Reflection

10.1364/oe.20.000b45

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Citations (10)

A WDM-PON with an 80 Gb/s capacity based on wavelength-locked polarisation independent Fabry-Perot laser diode

Hoon-Keun Lee Ho-Sung Cho Joon-Young Kim Sang-Hwa Yoo Chang-Hee Lee

We demonstrate a 80 Gb/s capacity (2.5 Gb/s × 32 channel) WDM-PON based on wavelength locked polarisation independent Fabry-Perot laser diode with transmission length of 20 km.

Laser diode

Channel spacing

10.1109/ecoc.2010.5621175

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Citations (2)

Noise Characteristics of a Wavelength-Locked Fabry–Perot Laser Diode

IEEE Journal of Quantum Electronics (2008)

Kun-Youl Park Chang-Hee Lee

We derived a theoretical model of a wavelength-locked Fabry-Perot laser diode (F-P LD) to a sliced spectrum of externally injected amplified spontaneous emission (ASE) from wave equations. The model explains the dynamics of the wavelength-locked F-P LD. Using this model, we investigated the noise characteristics of a wavelength-locked F-P LD with respect to the various parameters, such as, the injected ASE power, the bias current of F-P LD, and the wavelength detuning. We also investigated intensity noise increment by spectral filtering in optical access networks based on wavelength-locked F-P LDs.

Relative intensity noise

Laser diode

Amplified spontaneous emission

10.1109/jqe.2008.2000913

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Citations (18)

High Speed Imaging with Wide Field-of-View Laser Scanning for a MEMS Mirror-Based Lidar

2019 Asia Communications and Photonics Conference (ACP) (2019)

Pallab K. Choudhury Chang-Hee Lee

A MEMS mirror based wide filed-of-view Lidar is proposed for high speed imaging. The system uses the off-the-shelf simple optics to achieve 45° × 20° scanning view with 15 fps refresh rate.

Laser Scanning

Field of view

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Bidirectional Add/Drop Amplifier Module with a Single Dispersion Compensating Fiber Module

Optical Fiber Communication Conference and International Conference on Quantum Information (2001)

Hyun Deok Kim Jeong-Hun Shin Seongtaek Hwang Yunje Oh Chang-Hee Lee

We propose a new bidirectional add/drop amplifier (BADA) module to halve the dispersion compensation cost. We successfully demonstrate the bidirectional transmission and add/drop function of 10 Gb/s × 14 channels over 200-km of SMF by using the BADA module.

10.1364/ofc.2001.wh2

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Citations (3)

Development of a Flood Runoff and Inundation Analysis System Associated With 2-D Rainfall Data Generated Using Radar I. Quality Control and CAPPI Composite Calculation

Journal of Korea Water Resources Association (2006)

Kyu-Hyun Choi Kun-Yeun Han Kyung-Eak Kim Chang-Hee Lee

본 연구에서는 3차원 공간상에서 구면 좌표계값을 가지는 레이더 반사도 자료를 직교 좌표계로 변환하기 위한 CAPPI(Constant Altitude Plan Position Indicator) 산출 프로그램을 개발한다. 오염되지 않은 CAPPI 자료의 산출을 위해서 레이더 반사도 자료에 대한 품질검사 과정이 선행되었다. 개발된 모형은 3차원 공간상에서의 연속성을 유지하기 위해서 가장 근접하고 가장 적은 자료수를 운영함으로서 최적의 반사도 자료를 보간하였다. 개발된 모형은 자료의 이용목적에 따라서 다양한 해상도 및 고도에 대한 자료가 필요할 수 있다는 생각 하에 임의의 해상도 및 고도등에 대한 자료를 효율적으로 계산해 낼 수 있다. The need for economical and accurate presentations of equivalent radar reflectivity( $Z_e$) data in an orthogonal coordinate system has existed for some time. So, in this study, a fast and efficient procedure has been developed which allows the systematic interpolation of digital reflectivity data from radar space into Cartesian space. At first, QC(Quality Control) of radar data has been executed for extracting uncontaminated Constant Altitude Plan Position Indicator(CAPPI) data. The algorithm is designed so that only one ordered pass through the original Plan Position Indicator(PPI) scan data is necessary to complete the interpolation process. The model can calculate various resolution and altitude reflectivity data for many kinds of hydrological usage.

Interpolation

Position (finance)

10.3741/jkwra.2006.39.4.321

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Citations (1)