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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Optical Society of Korea
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Journal DOI :
Optical Society of Korea
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Volume & Issues
Volume 12, Issue 4 - Dec 2008
Volume 12, Issue 3 - Sep 2008
Volume 12, Issue 2 - Jun 2008
Volume 12, Issue 1 - Mar 2008
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6.25-Gb/s Optical Receiver Using A CMOS-Compatible Si Avalanche Photodetector
Kang, Hyo-Soon ; Lee, Myung-Jae ; Choi, Woo-Young ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 217~220
DOI : 10.3807/JOSK.2008.12.4.217
An optical receiver using a CMOS-compatible avalanche photodetector (CMOS-APD) is demonstrated. The CMOS-APD is fabricated with
standard CMOS technology and the optical receiver is implemented by using the CMOS-APD and a transimpedance amplifier on a board. The optical receiver can detect 6.25-Gb/s data with the help of the series inductive peaking effect.
Hydrogen Sensor Based on A Palladium-Coated Long-Period Fiber Grating Pair
Kim, Young-Ho ; Kim, Myoung-Jin ; Park, Min-Su ; Jang, Jae-Hyung ; Lee, Byeong-Ha ; Kim, Kwang-Taek ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 221~225
DOI : 10.3807/JOSK.2008.12.4.221
We propose a simple hydrogen detection scheme based on a Mach-Zehnder interferometer formed with a pair of palladium-coated long-period fiber gratings (LPGs). Since an LPG pair offered a fine-structured interference fringe in its transmission spectrum, the resolution as a sensor could be appreciably enhanced compared to that of a single LPG. As the palladium layer absorbed hydrogen, the effective refractive indices of the cladding modes were increased so that the interference spectrum was blue-shifted up to 2.3 nm with a wavelength sensitivity of -0.29 nm/min for 4% of hydrogen concentration.
Optimization of 40 Gb/s WDM Systems Using Super-Gaussian RZ Pulses
Lee, Jong-Hyung ; Han, Dae-Hyun ; Lee, Yong-Jae ; Choi, Byeong-Yoon ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 226~231
DOI : 10.3807/JOSK.2008.12.4.226
40 Gbps WDM Systems using super-Gaussian RZ pulses have been studied by numerical simulation to optimize their performance. The assumption of standard single mode fiber is valid when existing WDM systems are required to upgrade their performance to 40Gbps. It is shown that the standard single mode fiber can transmit optical signals over 720 km (Q > 10) by optimizing optical and electrical filter characteristics at the receiver and by compensation of dispersion. However, it is also shown that
dispersion compensation tolerance per span (80 km) could prohibit transmitting over 320km (Q > 10). In addition, a duty cycle of less than 0.4 degrades system performance significantly.
PMD Tolerance of 10 Gbps Modulated Signals due to SOA-Induced Chirp in SOA Booster Amplifiers
Jang, Ho-Deok ; Kim, Kyoung-Soo ; Lee, Jae-Hoon ; Jeong, Ji-Chai ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 232~239
DOI : 10.3807/JOSK.2008.12.4.232
We investigated how the polarization-mode dispersion (PMD) tolerance was degraded by semiconductor optical amplifier (SOA)-induced chirp for the 10 Gb/s nonreturn-to-zero (NRZ), duobinary NRZ, return-to-zero (RZ), and carrier-suppressed RZ (CS-RZ) modulation formats. The power penalty was calculated as a measure of the system performance due to PMD for a given SOA-induced chirp. Considering only first-order PMD, all modulation formats have a similar PMD tolerance regardless of SOA-induced chirp. On the other hand, when both first- and second-order PMD are considered, the PMD tolerance of all modulation formats with the exception of the CS-RZ modulation format are degraded by SOA-induced chirp. Among all modulation formats considered here, the NRZ modulation format has the PMD tolerance with the highest sensitivity to SOA-induced chirp. When the peak-to-peak chirp induced by SOAs is
, its PMD tolerance is degraded up to 4 dB for a differential group delay (DGD) of 50 ps. However, the PMD tolerance of the CS-RZ modulation format is largely unaffected by SOA-induced chirp.
Derivation of the Foschini and Shepp's Joint-Characteristic Function for the First-and Second-Order Polarization-Mode-Dispersion Vectors Using the Fokker-Planck Method
Lee, Jae-Seung ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 240~243
DOI : 10.3807/JOSK.2008.12.4.240
Using the well-known Fokker-Planck method, this paper presents a standard way to find the joint-characteristic function for the first- and second-order polarization-mode-dispersion vectors originally derived by Foschini and Shepp. Compared with the Foschini and Shepp's approach, the Fokker-Planck approach gives a more accurate and straightforward way to find the joint-characteristic function.
Performance Evaluation of A Tunable Dispersion Compensator based on Strain-Chirped Fiber Bragg Grating in a 40 Gb/s Transmission Link
Kim, Chul-Han ; Bae, Jun-Key ; Lee, Kwan-Il ; Lee, Sang-Bae ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 244~248
DOI : 10.3807/JOSK.2008.12.4.244
We have evaluated the performance of strain-chirped fiber Bragg grating (FBG) based tunable dispersion compensator in a 40 Gb/s transmission link. In our proposed compensator, the value of dispersion could be changed from -353 ps/nm to -962 ps/nm by adjusting the rotation angle of the metal beam on which the FBG was mounted. In order to evaluate the effect of ripples in reflectivity and variations in passband of the FBG based dispersion compensator, transmission performance has been measured with our tunable dispersion compensator. Error-free transmission of a 40 Gb/s non-return-to-zero (NRZ) signal over conventional single-mode fiber (SMF) was achieved.
An Electronic Domain Chromatic Dispersion Monitoring Scheme Insensitive to OSNR Using Kurtosis
Kim, Kyoung-Soo ; Lee, Jae-Hoon ; Chung, Won-Zoo ; Kim, Sung-Chul ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 249~254
DOI : 10.3807/JOSK.2008.12.4.249
In this paper we present an electronic domain solution for chromatic dispersion (CD) monitoring algorithm based on the estimated time domain channel in electronic domain using channel estimation methods. The proposed scheme utilizes kurtosis as a CD measurement, directly computed from the estimated inter-symbol-interference (ISI) channel due to the CD distortion. Hence, the proposed scheme exhibits robust performance under OSNR variation, in contrast to the existing electronic domain approach based on minimum mean squared error (MMSE) fractionally-spaced equalizer taps . The simulation results verify the CD monitoring ability of the proposed scheme.
Side-Coupled Asymmetric Plastic Optical Fiber Coupler for Optical Sensor Systems
Kim, Kwang-Taek ; Kim, Deok-Gi ; Hyun, Woong-Keun ; Hong, Ki-Bum ; Im, Kie-Gon ; Baik, Se-Jong ; Kim, Dae-Kyong ; Choi, Hyun-Yong ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 255~261
DOI : 10.3807/JOSK.2008.12.4.255
This paper reports a side-coupled asymmetric
plastic optical fiber coupler for an optical sensor system. The dependence of the optical power coupling ratio on the coupling angle and refractive index of the adhesion layer in both the forward and backward directions was examined based on the geometrical optics. It was confirmed experimentally that the coupling ratios can be optimized by controlling the coupling angle and refractive index of the adhesion layer. A maximum forward coupling efficiency > 93% was achieved.
Optical Design of A Compact Imaging Spectrometer for STSAT3
Lee, Jun-Ho ; Jang, Tae-Seong ; Yang, Ho-Soon ; Rhee, Seung-Wu ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 262~268
DOI : 10.3807/JOSK.2008.12.4.262
A compact imaging spectrometer (COMIS) for use in the STSAT3 microsatellite is currently under development. It is scheduled to be launched into a low Sun-synchronous Earth orbit (
) by the end of 2010. COMIS was inspired by the success of CHRIS, which is a small hyperspectral imager developed for the ESA microsatellite PROBA. COMIS is designed to achieve nearly equivalent imaging capabilities of CHRIS in a smaller (65 mm diameter and 4.3 kg mass) and mechanically superior (in terms of alignment and robustness) package. Its main operational goal will be the imaging of Earth's surface and atmosphere with ground sampling distances of
spectral bands (
). This imaging will be used for environmental monitoring, such as the in-land water quality monitoring of Paldang Lake, which is located next to Seoul, South Korea. The optics of COMIS consists of two parts: imaging telescope and dispersing relay optics. The imaging telescope, which operates at an f-ratio of 4.6, forms an image (of Earth's surface or atmosphere) onto an intermediate image plane. The dispersion relay optics disperses the image and relay it onto a CCD plane. All COMIS lenses and mirrors are spherical and are made from used silica exclusively. In addition, the optics is designed such that the optical axis of the dispersed image is parallel to the optical axis of the telescope. Previous efforts focused on manufacturing ease, alignment, assembly, testing, and improved robustness in space environments.
Hologram Generation of 3D Objects Using Multiple Orthographic View Images
Kim, Min-Su ; Baasantseren, Ganbat ; Kim, Nam ; Park, Jae-Hyeung ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 269~274
DOI : 10.3807/JOSK.2008.12.4.269
We propose a new synthesis method for the hologram of 3D objects using incoherent multiple orthographic view images. The 3D objects are captured and their multiple orthographic view images are generated from the captured image. Each orthographic view image is numerically overridden by the plane wave propagating in the direction of the corresponding view angle and integrated to form a point in the hologram plane. By repeating this process for all orthographic view images, we can generate the Fourier hologram of the 3D objects.
Elemental Image Synthesis for Integral Imaging Using Phase-shifting Digital Holography
Jeong, Min-Ok ; Kim, Nam ; Park, Jae-Hyeung ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 275~280
DOI : 10.3807/JOSK.2008.12.4.275
We propose a method generating elemental images for the integral imaging using 4-step phaseshifting digital holography. Phase shifting digital holography is a way recording the digital hologram by changing the phase of the reference beam and extracting the complex field of the object beam. Since all 3D information is captured by phase-shifting digital holography, the elemental images for any specifications of the lens array can be generated from single phase-shifting digital holography. In experiment, phase-shifting is achieved by rotating half- and quarter- wave plates and the resultant interference patterns are captured by a
pixel CCD camera with
3-D Surface Profile Measurement Using An Acousto-optic Tunable Filter Based Spectral Phase Shifting Technique
Kim, Dae-Suk ; Cho, Yong-Jai ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 281~287
DOI : 10.3807/JOSK.2008.12.4.281
An acousto-optic tunable filter based 3-D micro surface profile measurement using an equally spaced 5 spectral phase shifting is described. The 5-bucket spectral phase shifting method is compared with a Fourier-transform method in the spectral domain. It can provide a fast measurement capability while maintaining high accuracy since it needs only 5 pieces of spectrally phase shifted imaging data and a simple calculation in comparison with the Fourier transform method that requires full wavelength scanning data and relatively complicated computation. The 3-D profile data of micro objects can be obtained in a few seconds with an accuracy of
. The 3-D profile method also has an inherent benefit in terms of being speckle-free in measuring diffuse micro objects by employing an incoherent light source. Those simplicity and practical applicability is expected to have diverse applications in 3-D micro profilometry such as semiconductors and micro-biology.
Analysis of Temperature Effects on Raman Silicon Photonic Devices
Kim, Won-Chul ; Park, Dong-Wook ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 288~297
DOI : 10.3807/JOSK.2008.12.4.288
Recent research efforts on study of silicon photonics utilizing stimulated Raman scattering have largely overlooked temperature effects. In this paper, we incorporated the temperature dependences into the key parameters governing wave propagation in silicon waveguides with Raman gain and investigated how the temperature affects the solution of the coupled-mode equations. We then carried out, as one particular application example, a numerical analysis of the performance of wavelength converters based on stimulated Raman scattering at temperatures ranging from 298 K to 500 K. The analysis predicted, among other things, that the wavelength conversion efficiency could decrease by as much as 12 dB at 500 K in comparison to that at the room temperature. These results indicate that it is necessary to take a careful account of temperature effects in designing, fabricating, and operating Raman silicon photonic devices.
270-W 15-kHz MOPA System Based on Side-pumped Rod-type Nd:YAG Gain Modules
Cha, Yong-Ho ; Yang, Myoung-Yerl ; Ko, Kwang-Hoon ; Lim, Gwon ; Han, Jae-Min ; Park, Hyun-Min ; Kim, Taek-Soo ; Roh, Si-Pyo ; Jeong, Do-Young ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 298~302
DOI : 10.3807/JOSK.2008.12.4.298
We have developed a 270-W 15-kHz MOPA system based on side-pumped rod-type Nd:YAG gain modules. The master oscillator is a 3-W 15-kHz
laser with a pulse duration of 30 ns. To preserve the high beam quality during the amplification, we use image relay and polarization rotation which can simultaneously compensate for thermal lensing and thermal birefringence generated in the rod-type gain modules. After the amplification to 270 W with six rod-type gain modules, the beam quality factor (
) of the amplified laser beam is 5-10, and the pulse duration is maintained at 30 ns.
Amplitude Modulation Response and Linearity Improvement of Directly Modulated Lasers Using Ultra-Strong Injection-Locked Gain-Lever Distributed Bragg Reflector Lasers
Sung, Hyuk-Kee ; Wu, Ming C ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 303~308
DOI : 10.3807/JOSK.2008.12.4.303
Directly modulated fiber-optic links generally suffer higher link loss and larger signal distortion than externally modulated links. These result from the electron-photon conversion loss and laser modulation dynamics. As a method to overcome the drawbacks, we have experimentally demonstrated the RF performance of directly modulated, ultra-strong injection-locked gain-lever distributed Bragg reflector (DBR) lasers. The free-running DBR lasers exhibit an improved amplitude modulation efficiency of 12.4 dB under gain-lever modulation at the expense of linearity. By combining gain-lever modulation with ultra-strong optical injection locking, we can gain the benefits of both improved modulation efficiency from the gain-lever effect, plus improved linearity from injection locking. Using an injection ratio of R=11 dB, a 23.4-dB improvement in amplitude response and an 18-dB improvement in spurious-free dynamic range have been achieved.
Comparison of Sapphire and Germanium Fibers for Erbium : Yag Lithotripsy
Lee, Ho ; Yoon, Ji-Wook ; Jung, Young-Dae ; Kim, Jee-Hyun ; Ryan, Robert T. ; Teichman, Joel M.H. ; Welch, A.J. ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 309~313
DOI : 10.3807/JOSK.2008.12.4.309
We studied the sapphire and germanium fibers to determine which optical fiber best transmits Erbium:YAG laser for intracorporeal lithotripsy. Human calculi were ablated with an Erbium:YAG laser in contact mode using two fibers. Optical outputs at the distal end of fibers were measured before and after laser lithotripsy. Upon the irradiation on the calculus with the 50 mJ and 100 mJ pulse energy, the output energy at the distal end of germanium fiber declined to approximately 50% of the input energy. For the sapphire fiber, the output energy at the distal end remained unchanged with 100 mJ input energy; however the output energy had dropped to 50% for 200 mJ input energy. In order to examine how the types of target tissue affect the fiber damage, the sapphire fiber was tested for the irradiation on soft tissue and water as well. No energy decline was observed during soft tissue and water irradiation. We also characterized ablation craters with both optical fibers. Both fibers produced similar craters on calculi in terms of depth and diameter. Sapphire fibers are better suited than germanium fibers for Erbium:YAG lithotripsy in terms of the fiber damage.
Complete Tunneling of Light via Local Barrier Modes in A Composite Barrier with Metamaterials
Kim, Kyoung-Youm ; Kim, Sae-Hwa ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 314~318
DOI : 10.3807/JOSK.2008.12.4.314
We investigate the conditions of the complete tunneling of light across a composite barrier made of multiple layers involving metamaterials. It is shown that complete tunneling phenomena are related to the resonance transmission properties of local modes formed in barrier layers and that there are two distinctive kinds of local barrier modes involved in actual complete tunneling: the degenerate inner-barrier mode and the full barrier mode. Complete tunneling occurs via two successive mode couplings: from the incident plane wave to the plane wave in the transmission layer through the direct mediation of these two kinds of local barrier modes.
Phase Contrast Projection Display Using Photopolymer
Piao, Mei-Lan ; Kim, Nam ; Park, Jae-Hyeung ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 319~325
DOI : 10.3807/JOSK.2008.12.4.319
We propose a phase contrast filter using photopolymer, for the phase contrast projection display. The photopolymer has high photosensitivity such that its optically induced refractive index change has a linear dependency on the illuminating light intensity. We implemented a phase contrast projection display using photopolymer as a phase contrast filter. By controlling the refractive index change of the photopolymer, we successfully convert an input phase image into a high contrast intensity image. We also investigated the effect of the photopolymer illumination condition on the quality of the displayed intensity image. As a projector, we achieved 82% phase to intensity conversion efficiency, which implies that the proposed method can potentially have much higher light efficiency than conventional projection display.
WDM-PON Based on Wavelength Locked Fabry-Perot LDs
Lee, Chang-Hee ; Mun, Sil-Gu ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 326~336
DOI : 10.3807/JOSK.2008.12.4.326
A WDM-PON has been considered as an ultimate solution for access networks. However, there were many technical and practical issues for commercial deployment. These issues were solved with wavelength locked F-P LD and the WDM-PONs employing this optical source were commercialized. These WDM-PON systems have been deployed in Korea, Europe, and US. We reviewed wavelength locking technology and WDM-PON achievements. When we inject spectrum sliced broadband light into an F-P LD, the multimode output is changed to a quasi single mode. Then, we can use the single mode light for WDM signal transmission. The broad spectral gain of the semiconductor gain medium enables a color-free operation of WDM-PON, i.e., an identical ONT can be used for each user. The wavelength locking properties depend on many parameters, especially alignment of injection wavelength to a lasing mode, passband profile of AWG and front facet reflectivity of F-P LD. However, these dependencies can be reduced by proper design of the laser and the injection bandwidth. Thus, WDM-PON systems have been achieved with color-free operation.
RSOA-Based Wavelength-Reuse Gigabit WDM-PON
Kim, Byoung-Whi ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 337~345
DOI : 10.3807/JOSK.2008.12.4.337
This article presents the RSOA-based re-modulation schemes for practical application to the WDM-PON link. Emphasis is put on the three methods for reducing the residual downstream signal in the upstream transmission; the simplest one is to use the RSOA gain-saturation property, the second uses selective filtering of the adiabatic-chirped DFB-LD output spectrum, and the last uses a dynamic RSOA gain control by varying its driving current according to the incident binary signal. The reflection sensitivity in the proposed re-modulation link is also qualitatively presented in the cases of using two different types of seed light: coherent light from DFB-LD array and spectrum-sliced incoherent ASE light. We show experimental results of an error-free bidirectional gigabit transmission over 20 km at -30 dB reflection with the spectrum-sliced ASE seed light.
Performance Analysis of Metro WDM Star Network based on An Arrayed Waveguide Grating
Kirmani, Syed Abdul Mannan ; Shin, Seo-Yong ; Yang, Hyo-Sik ; Azeemi, Naeem Zafar ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 346~350
DOI : 10.3807/JOSK.2008.12.4.346
In this paper, we analyze the performance of a reliable, scalable, and cost-effective switchless wavelength division multiplexing (WDM) network based on an arrayed waveguide grating (AWG). The network efficiency is significantly increased by spatially reusing wavelengths and exploiting multiple free spectral ranges (FSRs) of the AWG employed in the architecture. We have analyzed the performance of this architecture by simulating in
with a control channel which exploits the broadband light source, i.e., an LED. The data was successfully transmitted to a distance of 30 km without using any EDFA's in the network, with a reasonable BER of
. We have analyzed the performance of this architecture with a control channel which exploits the broadband light source, i.e., an LED, by simulating in
Ultra-Dense WDM PON with 12.5-GHz Spaced 256 Channels
Yim, Jae-Nam ; Hwang, Gyo-Sun ; Lee, Jae-Seung ; Seo, Kyung-Hee ; Lee, Hyun-Jae ; Ko, Je-Soo ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 351~354
DOI : 10.3807/JOSK.2008.12.4.351
We demonstrate an ultra-dense wavelength-division- multiplexed (UD-WDM) passive optical network (PON) where 12.5-GHz spaced 1 GbE
256 optical channels are distributed using 12.5- and 200-GHz arrayed waveguide gratings in series. For the generation of upstream signals, we use reflective semiconductor optical amplifiers. We use two optical fiber amplifiers at the optical line terminal to amplify downstream and upstream channels.
Fabrication of 2.5 Gbps Burst-mode Receiver and its Full Compliance to GPON
Lee, Mun-Seob ; Lee, Byung-Tak ; Kim, Jong-Deog ; Lee, Dong-Soo ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 355~358
DOI : 10.3807/JOSK.2008.12.4.355
In the current GPON market and standard, the line bit rate requirement is changing from 1.25 Gbps to 2.5 Gbps. We fabricate a 2.5 Gbps burst-mode receiver with commercially available blocks and optimize it with an APD bias control. A burst-mode measurement setup is made for the full compliance test with the GPON standard. The device meets the partially defined 2.5 Gbps specs in the current ITU G.984.2 standard, also, supports 1.25 Gbps specs for the coexistence issue in an access network. The full-compliant measurement values can be used as a guideline for fixing "for further study" specs in the current GPON standard at 2.5 Gbps.
Bidirectional 1.25-Gbps WDM-PON with Broadcasting Function Using A Fabry-Perot Laser Diode and RSOA
Pham, Thang T. ; Kim, Hyun-Seung ; Won, Yong-Yuk ; Han, Sang-Kook ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 359~363
DOI : 10.3807/JOSK.2008.12.4.359
A novel WDM-PON system delivering bidirectional 1.25-Gbps data and broadcasting data is proposed. A subcarrier signal modulates optical carriers of a Fabry-Perot-laser-diode based broadband light source to broadcast to all users. Reflective semiconductor optical amplifiers are used as modulators for the baseband data at both the optical line terminal and the remote optical network unit for a channel. Bit error rate and error vector magnitude were measured to demonstrate the proposed scheme.
Speckle Reduction in Near-field Image of Multimode Fiber with a Piezoelectric Transducer[Author's Correction]
Ha, Woo-Sung ; Lee, Se-Jin ; Oh, Kyung-Hwan ; Jung, Yong-Min ; Kim, Jun-Ki ;
Journal of the Optical Society of Korea, volume 12, issue 4, 2008, Pages 364~364
DOI : 10.3807/JOSK.2008.12.4.364