Prof. Youngjoo Chung Profile

Prof. Youngjoo Chung

Professor at Gwangju Institute of Science and Technology

SPIE Involvement:

Author | Editor

Publications (35)

SPIE Journal Paper | 8 February 2023

Effect of incident light beam conditions on firing characteristics of the radial-firing optical fiber tip

Yong-Tak Ryu, Seongmin Ju, Bok Hyeon Kim, Youngjoo Chung, Won-Taek Han

OE, Vol. 62, Issue 02, 026104, (February 2023) https://doi.org/10.1117/12.10.1117/1.OE.62.2.026104

KEYWORDS: Optical simulations, Optical fibers, Incident light, Beam diameter, Optical engineering, Gaussian beams, Sodium, Cladding, Beam propagation method, Structured optical fibers

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Proceedings Article | 23 April 2017 Paper

Combined Sagnac and intermodal interferences for discrimination of strain and temperature variations

Guoyong Sun, Yingxin Cen, Liyan Zhao, Chuliang Wei, Youngjoo Chung

Proceedings Volume 10323, 103236Z (2017) https://doi.org/10.1117/12.2264594

KEYWORDS: Head, Error analysis, Signal attenuation, Refractive index, Sagnac interferometers, Birefringence, Sensors, Fiber optics sensors, Polarization, Temperature metrology, Photodetectors, Electromagnetism

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Proceedings Article | 23 April 2017 Paper

Quasi-distributed fiber sensor using active mode locking laser cavity with multiple FBG reflections

Chang Hyun Park, Gyeong Hun Kim, Chang-Seok Kim, Hwi Don Lee, Youngjoo Chung

Proceedings Volume 10323, 103235M (2017) https://doi.org/10.1117/12.2267642

KEYWORDS: Optical fibers, Reflectometry, Fiber Bragg gratings, Mode locking, Sensors, Fiber lasers, Modulation, Fiber optics sensors, Laser resonators, Active sensors

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Proceedings Article | 23 April 2017 Paper

High speed strain measurement of active mode locking FBG laser sensor using chirped FBG cavity

Gyeong Hun Kim, Joon Young Kim, Chang Hyun Park, Chang-Seok Kim, Hwi Don Lee, Youngjoo Chung

Proceedings Volume 10323, 103235L (2017) https://doi.org/10.1117/12.2267641

KEYWORDS: Fiber Bragg gratings, Mode locking, Sensors, Fiber lasers, Modulation, Pulse generators, Signal to noise ratio, Dispersion, Light sources, Laser resonators

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Proceedings Article | 28 September 2015 Paper

Torsion sensing characteristics of a highly birefringent photonic crystal fiber with two asymmetric cores in the Sagnac loop

Khurram Naeem, Bok Hyeon Kim, Youngjoo Chung

Proceedings Volume 9634, 96347K (2015) https://doi.org/10.1117/12.2194678

KEYWORDS: Photonic crystal fibers, Laser imaging, Birefringence, Visibility, Interferometers, Multiplexing, Spatial frequencies, Beam splitters, Optical fibers, Polarization

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Proceedings Article | 1 July 2015 Paper

Temperature sensitivity of the inline interferometer based on a two-core photonic crystal fiber selectively filled with polymer

Khurram Naeem, Bok Hyeon Kim, Bongkyun Kim, Youngjoo Chung

Proceedings Volume 9655, 96552G (2015) https://doi.org/10.1117/12.2184257

KEYWORDS: Polymers, Cladding, Photonic crystal fibers, Temperature metrology, Temperature sensors, Thermal optics, Polarization, Polymeric sensors, Interferometers, Mach-Zehnder interferometers

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Proceedings Article | 1 July 2015 Paper

All-fiber Sagnac loop hybrid interferometer based on a highly birefringent photonic crystal fiber with two asymmetric cores and its sensing applications

Khurram Naeem, Bok Hyeon Kim, Bongkyun Kim, Youngjoo Chung

Proceedings Volume 9655, 96551X (2015) https://doi.org/10.1117/12.2184255

KEYWORDS: Phase shifts, Interferometers, Photonic crystal fibers, Birefringence, Temperature metrology, Laser imaging, Beam splitters, Fourier transforms, Polarization, Fiber couplers

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Proceedings Article | 2 June 2014 Paper

Strain and temperature sensing characteristics of asymmetric-twin-core PCF-based hybrid Mach-Zehnder interferometer

Khurram Naeem, Bongkyun Kim, Youngjoo Chung

Proceedings Volume 9157, 915712 (2014) https://doi.org/10.1117/12.2059248

KEYWORDS: Interferometers, Mach-Zehnder interferometers, Polarization, Single mode fibers, Temperature metrology, Photonic crystal fibers, Spatial frequencies, Refractive index, Superposition, Fourier transforms

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Proceedings Article | 12 March 2014 Paper

Real-time stroboscopic full-field optical coherence tomography based on graphics processing unit

Kwan Seob Park, Hyounggyu Kim, Ju Wan Kim, Hee Gyu Baek, Jae Hwi Lee, Youngjoo Chung, Byeong Ha Lee

Proceedings Volume 8949, 89491O (2014) https://doi.org/10.1117/12.2039480

KEYWORDS: 3D acquisition, 3D image processing, Optical coherence tomography, Interferometers, Graphics processing units, CCD cameras, Light sources, Doppler tomography, Mirrors, Data acquisition

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Proceedings Article | 20 February 2014 Paper

Microstructured optical fiber-based micro-cavity sensor for chemical detection

Bongkyun Kim, Jin-Chul Ahn, Phil-Sang Chung, Youngjoo Chung

Proceedings Volume 8938, 89380L (2014) https://doi.org/10.1117/12.2041001

KEYWORDS: Micro optical fluidics, Optical fibers, Molecules, Reflectivity, Head, Sensors, Fiber optics sensors, Capillaries, Chemical analysis, Chemical detection

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Proceedings Article | 11 March 2013 Paper

Versatile chemical molecule sensing using multi-wavelength fiber laser based on inter-core interference in twin-core photonic crystal fiber

Bongkyun Kim, Khurram Naeem, Jihee Han, Youngjoo Chung

Proceedings Volume 8621, 86210J (2013) https://doi.org/10.1117/12.2005356

KEYWORDS: Fiber lasers, Molecules, Linear filtering, Photonic crystal fibers, Biological and chemical sensing, Molecular lasers, Molecular photonics, Photonic crystals, Light-matter interactions, Polarization

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Proceedings Article | 7 November 2012 Paper

Temperature and strain response of Michelson interferometer with asymmetric two-core photonic crystal fiber

Jihee Han, Bongkyun Kim, Khurram Naeem, Youngjoo Chung

Proceedings Volume 8421, 84217D (2012) https://doi.org/10.1117/12.975198

KEYWORDS: Michelson interferometers, Temperature metrology, Photonic crystal fibers, Single mode fibers, Polarization, Cladding, Fusion splicing, Photomicroscopy, Scanning electron microscopy, Interferometers

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Proceedings Article | 7 November 2012 Paper

Individual or simultaneous temperature and strain monitoring by high birefringence fiber loop mirror with reduced cross sensitivity

Guoyong Sun, Shaohui Li, Youngjoo Chung

Proceedings Volume 8421, 842198 (2012) https://doi.org/10.1117/12.975133

KEYWORDS: Birefringence, Mirrors, Temperature metrology, Head, Fiber optics sensors, Polarization, Fiber in the loop, Fusion splicing, Sensors, Environmental monitoring

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Proceedings Article | 7 November 2012 Paper

Inline Mach-Zehnder interferometer using liquid filled twin-core photonic crystal fiber with high strain sensitivity.

Khurram Naeem, Bongkyun Kim, Jihee Han, Youngjoo Chung

Proceedings Volume 8421, 842179 (2012) https://doi.org/10.1117/12.975174

KEYWORDS: Liquids, Mach-Zehnder interferometers, Photonic crystal fibers, Refractive index, Bioalcohols, Polarization, Fusion splicing, Optical sensors, Optical components, Single mode fibers

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Proceedings Article | 7 November 2012 Paper

Chemical vapor sensing properties of twin-core photonic crystal fiber based in-reflection interferometer

Bongkyun Kim, Khurram Naeem, Jihee Han, Youngjoo Chung

Proceedings Volume 8421, 84216J (2012) https://doi.org/10.1117/12.975244

KEYWORDS: Interferometers, Photonic crystal fibers, Molecules, Bioalcohols, Biological and chemical sensing, Single mode fibers, Atmospheric propagation, Photonic crystals, Sensors, Silica

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Proceedings Article | 2 March 2012 Paper

Tunable and switchable multi-wavelength fiber laser based on semiconductor optical amplifier and twin-core photonic crystal fiber

Bongkyun Kim, Jihee Han, Youngjoo Chung

Proceedings Volume 8257, 82570F (2012) https://doi.org/10.1117/12.909447

KEYWORDS: Fiber lasers, Polarization, Photonic crystal fibers, Semiconductor optical amplifiers, Linear filtering, Silica, Single mode fibers, Telecommunications, Wavelength division multiplexing, Mach-Zehnder interferometers

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SPIE Journal Paper | 1 September 2010

Comparative study of Raman fiber laser in symmetrical and asymmetrical cavities

Young-Eun Im, Kyungwon Chun, Hangeul Kim, Dong-Hwan Kim, Swook Hann, Youngjoo Chung, Chang-Soo Park

OE, Vol. 49, Issue 09, 091008, (September 2010) https://doi.org/10.1117/12.10.1117/1.3484948

KEYWORDS: Fiber Bragg gratings, Raman spectroscopy, Fiber lasers, Reflectivity, Laser resonators, Reflectors, Output couplers, Raman scattering, Optical engineering, Resonators

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Proceedings Article | 5 October 2009 Paper

Demonstration of stable raman fibre laser with asymmetrical laser cavity including broadband chirped FBG

Young-Eun Im, Kyungwon Chun, Hangeul Kim, Swook Hann, Dong-Hwan Kim, Youngjoo Chung, Chang-Soo Park

Proceedings Volume 7503, 75036P (2009) https://doi.org/10.1117/12.835357

KEYWORDS: Fiber Bragg gratings, Raman spectroscopy, Laser resonators, Reflectivity, Reflectors, Fiber lasers, Output couplers, Resonators, Raman scattering, High power lasers

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Proceedings Article | 5 October 2009 Paper

Compact in-reflection fiber interferometer using thermally expanded core fiber and single-mode fiber and its applications as temperature and refractive index sensors

Linh Viet Nguyen, Youngjoo Chung

Proceedings Volume 7503, 75033P (2009) https://doi.org/10.1117/12.834075

KEYWORDS: Single mode fibers, Interferometers, Cladding, Refractive index, Fiber optics sensors, Sensors, Water, Temperature metrology, Superluminescent sources, Bioalcohols

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Proceedings Article | 13 November 2008 Paper

Discretely tunable SOA-fiber laser based on few-mode polarization maintaining fiber in Sagnac interferometer

Guoyong Sun, Dae Moon, Youngjoo Chung

Proceedings Volume 7134, 71342Y (2008) https://doi.org/10.1117/12.801993

KEYWORDS: Fiber lasers, Tunable lasers, Interferometers, Semiconductor lasers, Polarization maintaining fibers, Sagnac interferometers, Birefringence, Semiconductor optical amplifiers, Polarization, Fiber optic communications

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Proceedings Article | 16 May 2008 Paper

Simultaneous measurement for temperature and strain by use of Sagnac interferometer with controlled sensitivity

Guoyong Sun, Dae Seung Moon, Aoxiang Lin, Won-Taek Han, Youngjoo Chung

Proceedings Volume 7004, 70041Y (2008) https://doi.org/10.1117/12.785896

KEYWORDS: Sagnac interferometers, Optical fibers, Temperature metrology, Head, Fiber optics sensors, Birefringence, Polarization, Mirrors, Sun, Fiber Bragg gratings

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Proceedings Article | 16 May 2008 Paper

Intensity based optical fiber strain sensor using long period grating and core mode blocker

Du-sun Hwang, Linh Viet Nguyen, Dae Seung Moon, Youngjoo Chung

Proceedings Volume 7004, 70044E (2008) https://doi.org/10.1117/12.786077

KEYWORDS: Sensors, Optical fibers, Fiber optics sensors, Bandpass filters, Near field, Optical testing, Optical power meters, Fiber Bragg gratings, Environmental sensing, Phase matching

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Proceedings Article | 16 May 2008 Paper

Simultaneous measurement of strain and temperature using a Lyot fiber filter and a fiber Bragg grating in linear configuration

Linh Viet Nguyen, Dusun Hwang, Dae Seung Moon, Youngjoo Chung

Proceedings Volume 7004, 70044D (2008) https://doi.org/10.1117/12.786061

KEYWORDS: Temperature metrology, Fiber Bragg gratings, Sensors, Optical filters, Phase modulation, Fiber optics sensors, Polarizers, Linear filtering, Birefringence, Fusion splicing

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Proceedings Article | 16 May 2008 Paper

Simultaneous measurement of bending and temperature incorporating a sampled chirped fiber Bragg grating

Young-Geun Han, Chang-Seok Kim, Youngjoo Chung

Proceedings Volume 7004, 70045A (2008) https://doi.org/10.1117/12.786234

KEYWORDS: Temperature metrology, Fiber Bragg gratings, Sensors, Thermography, Tunable filters, Optical fibers, Ultraviolet radiation, Error analysis, Hydrogen, Physics

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Proceedings Article | 21 November 2007 Paper

Theoretical analysis of feedback high birefringence fiber loop mirror with dramatically enhanced free spectral range

Guoyong Sun, Dae Seung Moon, Youngjoo Chung

Proceedings Volume 6781, 678131 (2007) https://doi.org/10.1117/12.745373

KEYWORDS: Resonators, Mirrors, Polarization, Birefringence, Fiber lasers, Optical filters, Beryllium, Feedback loops, Electronic filtering, Fiber optics sensors

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SPIE Journal Paper | 1 May 2007

Effects of boron in Ge-B co-doped fiber on the spectral characteristics of optical fiber gratings

Dae Seung Moon, Youngjoo Chung, Young-Geun Han

OE, Vol. 46, Issue 05, 054401, (May 2007) https://doi.org/10.1117/12.10.1117/1.2740747

KEYWORDS: Boron, Cladding, Optical fibers, Fiber Bragg gratings, Germanium, Hydrogen, Temperature metrology, Ultraviolet radiation, Optical engineering, Fiber optic communications

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SPIE Journal Paper | 1 January 2007

Multiwavelength fiber laser based on semiconductor optical amplifier and few-mode fiber gratings

Dae Seung Moon, Youngjoo Chung, Young-Geun Han

OE, Vol. 46, Issue 01, 014202, (January 2007) https://doi.org/10.1117/12.10.1117/1.2431357

KEYWORDS: Fiber lasers, Semiconductor optical amplifiers, Fiber Bragg gratings, Polarization, Fiber amplifiers, Erbium, Optical engineering, Tunable lasers, Optical filters, Semiconductor lasers

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Proceedings Article | 4 October 2006 Paper

Multi-wavelength SOA-fiber laser with versatile multichannel filters based on fiber Bragg gratings

Dae Seung Moon, Young-Geun Han, Xinyong Dong, Ping Shum, Youngjoo Chung

Proceedings Volume 6351, 63512H (2006) https://doi.org/10.1117/12.691617

KEYWORDS: Fiber lasers, Fiber Bragg gratings, Ultraviolet radiation, Polarization, Optical filters, Linear filtering, Laser resonators, Tunable lasers, Single mode fibers, Temperature metrology

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Proceedings Article | 6 December 2005 Paper

Fiber Bragg grating-based multi-wavelength fiber lasers using erbium-doped fiber

Youngjoo Chung, Dae Seung Moon, Du-Sun Hwang, Un-Chul Paek

Proceedings Volume 6019, 60190V (2005) https://doi.org/10.1117/12.639289

KEYWORDS: Fiber lasers, Fiber Bragg gratings, Polarization, Laser resonators, Semiconductor lasers, Mirrors, Tunable lasers, Optical filters, Photomasks, Spectrum analysis

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SPIE Journal Paper | 1 June 2005 Open Access

Upstream signal transmission using a self-injection locked Fabry-Perot laser diode for WDM-PON

Swook Hann, Dae Moon, Youngjoo Chung, Chang Soo Park

OE, Vol. 44, Issue 06, 060509, (June 2005) https://doi.org/10.1117/12.10.1117/1.1920069

KEYWORDS: WDM-PON, Fiber Bragg gratings, Radon, Fabry–Perot interferometers, Semiconductor lasers, Passive optical networks, Optical networks, Control systems, Polarization, Temperature metrology

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SPIE Journal Paper | 1 May 2004

Compositional dependence of the temperature sensitivity in long-period fiber gratings with doping concentration of GeO₂ and B2O₃ and their applications

Young-Geun Han, Sang Bae Lee, Youngjoo Chung

OE, Vol. 43, Issue 05, (May 2004) https://doi.org/10.1117/12.10.1117/1.1690280

KEYWORDS: Cladding, Doping, Temperature metrology, Optical amplifiers, Sensors, Structured optical fibers, Refractive index, Optical filters, Thermal optics, Fiber Bragg gratings

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Proceedings Article | 25 June 2002 Paper

Temperature dependent chromatic dispersion measurement using long-period fiber grating

Young-Jae Kim, EunSeo Choi, Youngjoo Chung, Won-Taek Han, Un-Chul Paek, Byeong Ha Lee

Proceedings Volume 4639, (2002) https://doi.org/10.1117/12.481331

KEYWORDS: Cladding, Dispersion, Refractive index, Temperature metrology, Germanium, Silica, Optical fibers, Single mode fibers, Doping, Waveguides

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Proceedings Article | 25 April 2002 Paper

Optical properties measurement of several photonic crystal fibers

Joo Eom, Kun Park, Youngjoo Chung, Won-Taek Han, Un-Chul Paek, Dug Kim, Byeong Ha Lee

Proceedings Volume 4655, (2002) https://doi.org/10.1117/12.463867

KEYWORDS: Photonic crystal fibers, Optical fibers, Silica, Optical testing, Optical properties, Capillaries, Cladding, Light sources, Objectives, Cameras

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Proceedings Article | 19 October 2001 Paper

Measurement of refractive index change due to CO2 laser irradiation using an LPG pair in optical fibers

Bokhyeon Kim, Tae-Jung Ahn, Y. Park, D.Y. Kim, Byeong Ha Lee, Youngjoo Chung, Un-Chul Paek, Won-Taek Han

Proceedings Volume 4579, (2001) https://doi.org/10.1117/12.444907

KEYWORDS: Gas lasers, Carbon monoxide, Laser irradiation, Refractive index, Optical fibers, Cladding, Fiber lasers, Carbon dioxide lasers, Ultraviolet radiation, Glasses

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Proceedings Article | 19 October 2001 Paper

Torsion sensing characteristics of optical fiber with a long-period grating pair

Tae-Jung Ahn, B.H. Kim, Byeong Ha Lee, Youngjoo Chung, Un-Chul Paek, Won-Taek Han

Proceedings Volume 4579, (2001) https://doi.org/10.1117/12.444882

KEYWORDS: Optical fibers, Polarization, Polarizers, Sensors, Ultraviolet radiation, Optical sensing, Birefringence, Refractive index, Gas lasers, Glasses

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