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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Korean Journal of Optics and Photonics
Journal Basic Information
Journal DOI :
Optical Society of Korea
Editor in Chief :
Volume & Issues
Volume 16, Issue 6 - Dec 2005
Volume 16, Issue 5 - Oct 2005
Volume 16, Issue 4 - Aug 2005
Volume 16, Issue 3 - Jun 2005
Volume 16, Issue 2 - Feb 2005
Volume 16, Issue 1 - Feb 2005
Selecting the target year
Coupling Intensity Effects in Ladder-type Electromagnetically Induced Transparency of Rb atoms
Moon, H.S. ; Lee, L. ; Kim, J.B. ;
Korean Journal of Optics and Photonics, volume 16, issue 1, 2005, Pages 1~6
DOI : 10.3807/KJOP.2005.16.1.001
We have studied the polarization effects and the coupling intensity effects of electromagnetically induced transparency(EIT) in the 5S
2/ ladder system of Rb. We obtained the EIT spectrum with the hyperfine structure of 5D
2/ transitions and the minimal width of the measured EIT spectrum was 6.5 MHz. We observed the change of the relative magnitudes of the hyperfine structure of EIT according to not only the polarizations of lasers but also the intensity of the coupling laser. The cause of the coupling intensity effects is that the EIT signal nonlinearly increases to the coupling intensity.
Nonlinear magneto-optic effect based on atomic coherence in Rb D
Moon, H.S. ; Lee, W.K. ; An, M.H. ; Kim, J.B. ;
Korean Journal of Optics and Photonics, volume 16, issue 1, 2005, Pages 7~12
DOI : 10.3807/KJOP.2005.16.1.007
We have observed the nonlinear magneto-optic effect(NMOE) based on atomic coherence in
-line using the Rb vapor cell containing 50 Torr of Ne. The width of the NMOE signal was measured to be 2
464 Hz, when the peak-to-peak B-field variation was 1 mGauss. The result of this work may be applied to a high-sensitivity magnetometer.
Fabrication and performance analysis of cost-effective fiber grating lasers for WDM-PON systems
Cho, Seung-Hyun ; Lee, Woo-Ram ; Lee, Jie-Hyun ; Park, Jae-Dong ; Kim, Byoung-Whi ; Kang, Min-Ho ; Shin, Dong-Wook ;
Korean Journal of Optics and Photonics, volume 16, issue 1, 2005, Pages 13~20
DOI : 10.3807/KJOP.2005.16.1.013
Fiber-Bragg-grating external cavity laser(FGL) modules were fabricated and experimentally analyzed. Proposed as a cost-effective solution for optical sources in the WDM-PON access network, FGL modules were packaged to TO-CAN type. We obtained a low threshold current of 13 mA, and an optical output power of 3.6 mW with a bias current of 60 mA at
. The lasing wavelength dependencies on current and temperature were as small as 5.2 pm/mA and 30 pm/
, respectively. These change rates of the wavelength with the temperature and current are smaller than those of the DFB laser. Single-mode oscillations with the side-mode suppression ratio(SMSR) over 30 dB are maintained above the threshold current level. The FGL modules can be directly modulated at 155 Mbps, PRBS(2
-1) NRZ signal. Through the BER plots, we did not see the significant degradations before and after the transmission over 20km of the SMF at 155 Mb/s.
Theoretical and experimental study on ultrahigh-speed clock recovery system with optical phase lock loop using TOAD
Ki, Ho-Jin ; Jhon, Young-Min ; Byun, Young-Tae ; Woo, Deok-Ha ;
Korean Journal of Optics and Photonics, volume 16, issue 1, 2005, Pages 21~26
DOI : 10.3807/KJOP.2005.16.1.021
10 GHz clock recovery from 40 Gbit/s optical time-division-multiplexed(OTDM) signal pulses was experimentally demonstrated using an optical phase lock loop based on a terahertz optical asymmetric demultiplexer(TOAD) with a local-reference-oscillator-free electronic feedback circuit. The 10 GHz clock was successfully extracted from 40 Gbit/s signals. The SNR of the time-extracted 10 GHz RF signal to the side components was larger than 40 dB. Also we performed numerical simulation about the extraction process of phase information in TOAD. The lock-in frequency range of the clock recovery is found to be 10 kHz.
New wavelength converter for optical NRZ data signal using SOA-loop-mirror
Lee, Hyuek-Jae ;
Korean Journal of Optics and Photonics, volume 16, issue 1, 2005, Pages 27~33
DOI : 10.3807/KJOP.2005.16.1.027
In this paper, a new wavelength converter using an SOA(Semiconductor Optical Amplifier)-loop-mirror for NRZ(NonReturn to Zero) optical data has been proposed and experimentally demonstrated. Conventional nonlinear fiber-loop-mirror methods can perform RZ-to-RZ, NRZ-to-RZ, and RZ-to-NRZ data format conversion, but NRZ-to-NRZ conversion has not been demonstrated until now. The experiment for the conversion from a 1300 nm NRZ data signal at 1.5 Gbps to a 1550 nm NRZ data one is successfully performed using a fiber-loop-mirror with 1300 nm-SOA.
Zoom lens design for compact digital camera using lens modules
Park, Sung-Chan ; Lee, Sang-Hun ;
Korean Journal of Optics and Photonics, volume 16, issue 1, 2005, Pages 34~42
DOI : 10.3807/KJOP.2005.16.1.034
This paper presents the optimum initial design containing the first and third order properties of the three-group zoom system using lens modules, and the real lens design of the system. The optimum initial design with focal length range of 4.3 mm to 8.6 mm is derived by assigning appropriate first and third order quantities to each module along with the specific constraints required for the system. An initial real lens selected for each group has been designed to match its focal length and the first orders into those of the each lens modules, and then combined to establish an actual zoom system by adjusting the air space between the groups at all zoom positions. The combination of the separately designed groups results in a system which satisfies the first order properties of the zoom system composed of the original lens modules. As a result, by residual aberration correction, we could obtain a zoom system useful in compact digital zoom cameras and mobile phone cameras employing the rear focus method.
Improvement of the efficiency from Computer-Generated Holograms by using TS algorithm and SA algorithm
Cho, Chang-Sub ; Shin, Chang-Mok ; Cho, Kyu-Bo ; Kim, Soo-Joong ; Kim, Cheol-Su ;
Korean Journal of Optics and Photonics, volume 16, issue 1, 2005, Pages 43~49
DOI : 10.3807/KJOP.2005.16.1.043
In this paper, we propose a method for optimizing a computer-generated hologram(CGH) by combining the Tabu Search(TS) algorithm with the Simulated Annealing(SA) algorithm. By replacing an initial random pattern of the SA algorithm with an approximately ideal hologram pattern of the TS algorithm, we design a CGH which has high diffraction efficiency(DE). We compared the performance of the proposed algorithm with the SA algorithm using computer simulation and an optical experiment. As a result, we confirmed diffraction efficiency and uniformity to be enhanced in the proposed algorithm.
MTF and wavefront error testing of large aperture optical system using unequal path interferometer
Song, Jong-Sup ; Jo, Jae-Heung ; Lee, Yun-Woo ; Song, Jae-Bong ; Yang, Ho-Soon ; Lee, In-Won ;
Korean Journal of Optics and Photonics, volume 16, issue 1, 2005, Pages 50~55
DOI : 10.3807/KJOP.2005.16.1.050
A method for measuring the wavefront error and the modulation transfer function(MTF) of large aperture optics using an unequal path interferometer is presented. A bidirectional shearing interferometer is used for collimation testing of the measurement system. A large aperture Fizeau interferometer with long optical path difference measures the wavefront error of the optics under test by using a
400 mm off-axis parabolic mirror. The MTF is also measured at the wavelength of the interferometer by changing the laser light into partially incoherent light. Test results of a
300 mm Cassegrain type satellite telescope made in Korea are presented.
Backward Testing Method of MTF measurement for optical engine of CRT of rear projection HDTV
Song, Jong-Sup ; Jo, Jae-Heung ; Hong, Sung-Mok ; Lee, Yun-Woo ; Song, Jae-Bong ; Lee, Hoe-Yun ; Lee, In-Won ;
Korean Journal of Optics and Photonics, volume 16, issue 1, 2005, Pages 56~62
DOI : 10.3807/KJOP.2005.16.1.056
Because of the wide plane and the curved field of CRT rear projection high definition television, its MTF(modulation transfer function) can`t be easily measured by the usual forward testing method. Then we propose a backward testing method for the MTF so that the object plane and the image analyzer of forward testing are located at positions opposite each other. We prefer to use the backward testing method because the forward testing method has poor accuracy caused by very small numerical aperture, low spatial resolutions, and long depth of focus. We found that the backward testing method was very easy to align and had high repeatability. We confirmed the confidence of results obtained by the backward testing method in comparison with designed results.
Image quality assessment of color LCD monitors by polychromatic modulation transfer function
Song, Jong-Sup ; Jo, Jae-Heung ; Hong, Sung-Mok ; Lee, Yun-Woo ; Yang, Ho-Soon ; Cho, Hyun-Mo ; Lee, In-Won ;
Korean Journal of Optics and Photonics, volume 16, issue 1, 2005, Pages 63~70
DOI : 10.3807/KJOP.2005.16.1.063
We propose a method for evaluating the image quality of color liquid crystal display(LCD) monitors by using the polychromatic modulation transfer function(PMTF), which is calculated from the modulation transfer function(MTF) weighted by the overall color response of the system including the test LCD monitor. We confirm that experimental results using the PMTF agree well with simulated results of the PMTF of a color LCD monitor by using three bar targets with different amplitudes and three elementary colors such as red(R), green(G), and blue(B). As a results, we should choose the PMTF instead of the white color MTF or monochromatic MTF in order to evaluate correctly the image quality of color LCD monitors.
A study for null lens design of autostigmatic type and the limitation of measurement accuracy for ultra precision manufacturing of large aspherical surface
Kim, Kil-Seon ; Rim, Cheon-Seog ;
Korean Journal of Optics and Photonics, volume 16, issue 1, 2005, Pages 71~78
DOI : 10.3807/KJOP.2005.16.1.071
A null lens system of autostigmatic type, consisting of two mirrors, is designed for testing a large aspherical mirror. The system is theoretically analyzed to determine the limitation of measurement accuracy according to the manufacturing and alignment errors. We confirmed that irregularity of the null lens surface is the principal factor among tolerances in limiting measurement accuracy. Consequently, we can predict that measurement accuracy will be from 5λ/100 to 4λ/1000 according to the amount of this irregularity. That is, we can present the limitation of possible measurement accuracy with actual alignment and manufacturing errors.
Large core polymeric single mode waveguide for passive fiber alignment
Cho, Su-Hong ; Beak, Yu-Jin ; Oh, Min-Choel ;
Korean Journal of Optics and Photonics, volume 16, issue 1, 2005, Pages 79~84
DOI : 10.3807/KJOP.2005.16.1.079
To increase the tolerance for passive fiber alignment, a single mode polymer waveguide with a large core structure is demonstrated. The large core waveguide is designed to have a mode profile comparable to that of a thermally expanded core (TEC) fiber, and it can be connected to a high-contrast waveguide through an adiabatic transition taper structure. From a waveguide with a rectangular core of 25
, a single mode propagation is observed when the index contrast is as low as 0.0005. A UV-cured injection molding method is used to fabricate the thick core structure. Due to the large mode size, the insertion loss of the device is below 0.5 dB until the lateral displacement of the TEC fiber is 4.5
. The low insertion loss is important for reproducible passive alignment.
Effect of varying the coupling strength and section length on the self-pulsation characteristics of multisection index-coupled DFB lasers
Kim, Sang-Taek ; Kim, Tae-Young ; Ji, Sung-Keun ; Kim, Boo-Gyoun ;
Korean Journal of Optics and Photonics, volume 16, issue 1, 2005, Pages 85~98
DOI : 10.3807/KJOP.2005.16.1.085
As the number of compound cavity modes within the stopband of DFB sections decreases, the frequency of mode hopping decreases for the variation of
, which represents the difference between the Bragg wavelengths of two DFB sections, so that the number of abrupt changes of pulsation frequencies decreases. In addition, the pulsation frequency varies continuously for the variation of the phase in a phase tuning section for a fixed
. The number of compound cavity modes within the stopband decreases as the length of DFB sections increases and the length of a phase tuning section decreases. Thus stable self-pulsation operations for the variation of
and the phase in a phase tuning section could be obtained by proper selection of the coupling strength and the length of each section.ction.
Wavelength tunability of a fiber ring laser using a novel strain device
Kim, Sung-Chun ; Jang, Hyun-Soo ; Lee, Kyung-Shik ;
Korean Journal of Optics and Photonics, volume 16, issue 1, 2005, Pages 99~102
DOI : 10.3807/KJOP.2005.16.1.099
We fabricated a tunable fiber ring laser consisting of a novel strain device and fiber Bragg gratings. The lasing power and FWHM bandwidth of the optical fiber ring laser was -12dBm and 0.05nm respectively. The fiber ring laser was tuned as much as 10nm at a 8000.
Frequency conversion using anomalous dispersion of organic material
Kim, Eung-Soo ; Kim, Min-Sung ; Kang, Shin-Won ;
Korean Journal of Optics and Photonics, volume 16, issue 1, 2005, Pages 103~108
DOI : 10.3807/KJOP.2005.16.1.103
Second harmonic generation(SHG) by guided phase matching is observed in waveguide structure using the anomalous dispersion of a poled polymer. The second harmonic TM
guided mode could be generated from the fundamental TM
guided mode and then the second harmonic power was higher than any other phase matchable mode because the overlap integral between the fundamental and the second harmonic wave was the largest in the theoretical analysis. Near UV SHG(370 nm) was obtained from the fundamental wavelength of Ti-sapphire laser(740 nm).