Browsing by Author "KAO, MS"

Now showing 1 - 14 of 14

BIDIRECTIONAL OPTICAL FIBER TRANSMISSION-SYSTEMS USING RAMAN AMPLIFICATION
(1988-02-01)
CHI, S
;
KAO, MS
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光電工程學系
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Department of Photonics
COHERENT OPTICAL RING USING COMMON LOCAL OSCILLATOR
(1990-07-05)
KAO, MS
;
WU, J
;
電信工程研究所
;
Institute of Communications Engineering
COHERENT SUBCARRIER MULTIPLEXED STAR DISTRIBUTION-SYSTEM USING SINGLE LOCAL OSCILLATOR
(1990-09-27)
KAO, MS
;
WU, J
;
交大名義發表
;
National Chiao Tung University
CONCEPTUAL SURVEY OF PHASE MODULATION BASED WAVELENGTH REGISTERED NETWORKS
(1994-02-01)
KAO, MS
;
LIN, TC
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電信工程研究所
;
電信研究中心
;
Institute of Communications Engineering
The implementation of a dense wavelength-division multiplexing (WDM) based wide-area network inevitably involves a large number of semiconductor lasers requiring particular temperature and driving current control. The concept of a novel multiwavelength network that uses only one laser source to generate all the carriers needed for the entire network is investigated. The central idea is to use a stable reference laser to generate two sets of optical carriers as the 'carrier supplies' for all network nodes: one set for signal transmission and the other for signal reception. A promising feature of the proposed network is the wavelength registration, that is, all carrier wavelengths are unambiguously identified. This special feature is of importance for a standard wide-area multiwavelength network. Optical phase modulation is extensively employed in the carrier generation as well as in information delivery. A 40-wavelength network is considered with each wavelength carrying 20 phase-modulated microwave subcarriers, a total throughput of 160 Gbit/s per single-mode fibre is estimated.
EFFECT OF POLARIZATION MODE DISPERSION ON A COHERENT OPTICAL-SYSTEM WITH PILOT CARRIER
(1993-02-01)
KAO, MS
;
WU, JS
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電信工程研究所
;
Institute of Communications Engineering
The effect of fiber polarization mode dispersion (PMD) on a coherent optical system with pilot carrier is twofold. First, the PMD causes state of polarization (SOP) mismatch between the message signal and pilot carrier. Second, the degrees of polarization (DOP) of the message signal and pilot carrier are degraded by PMD. Because coherent reception relies both on the SOP's and DOP's of the waves, system performance is degraded by PMD. The effect of SOP mismatch causes intermediate frequency (IF) signal amplitude degradation whereas DOP variation not only results in IF signal amplitude degradation but further induces IF noises. Here we derive analytical expressions to evaluate the performance degradation. It is shown that there is no performance degradation if only one principle state of polarization is excited and maximum degradation occurs when both principle states of polarization are equally excited. We also find that significant degradation may happen when large differential group delay exists.
EXTENDING TRANSMISSION DISTANCE OF HIGH-DENSITY WDM SYSTEMS USING POST TRANSMITTER FIBER RAMAN AMPLIFIERS
(1991-03-01)
KAO, MS
;
WU, JS
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電信工程研究所
;
Institute of Communications Engineering
We investigate the behavior of the multichannel signals in a high-density WDM system with the consideration of stimulated Raman scattering. We provide a parameter to evaluate the depth of Raman crosstalk and analyze the transmission distance limitation imposed by Raman crosstalk. To extend the system transmission distance, a post transmitter fiber Raman amplifier is employed. The allocation of signal channels on the pump gain profile is discussed. We found that there exists an optimum pump power which results in a maximum amplifier gain. The example shows that the transmission distance limitation imposed by Raman crosstalk can be extended by 20 km for a 30-channel system with 0.25-dB/km fiber loss.
EXTINCTION RATIO DEGRADATION IN RAMAN AMPLIFIED OPTICAL COMMUNICATION-SYSTEM
(1991-07-04)
KAO, MS
;
CHI, S
;
電信工程研究所
;
光電工程學系
;
電信研究中心
The extinction ratio of a Raman amplified optical fibre system is investigated. The results show that serious extinction ratio degradation occurs at high pump level. Because the Raman gain increases with pump power, there exists a trade-off between the extinction ratio and the achievable amplifier gain. A design rule to estimate the suitable pump power is presented.
HIGH-SPEED OPTICAL RECEIVER WITH SOFT DECISION ISI CANCELLATION
(1993-02-01)
CHIANG, PY
;
KAO, MS
;
電信工程研究所
;
電信研究中心
;
Institute of Communications Engineering
Due to the stimulating success in developing optical amplifiers, intersymbol interference (ISI) will become the dominant limit on both bit rate and transmission distance in long-haul optical fiber communication systems. Here we present a receiver with ''Soft Decision ISI Cancellation'' (SDIC) to deal with ISI in high-speed lightwave systems. The analytical and simulation results show that the transmission distance can be doubled with SDIC. In addition, the receiver with SDIC allows the ISI cancellation circuit operating with processing and propagation delay much longer than 1-b period. Therefore, it is very promising in very high bit rate optical systems.
ON OFF RATIO DEGRADATION OF HIGH-DENSITY WDM SYSTEMS DUE TO RAMAN CROSSTALK
(1990-07-05)
KAO, MS
;
交大名義發表
;
電信工程研究所
;
National Chiao Tung University
;
Institute of Communications Engineering
PERFORMANCE ANALYSIS OF WAVELENGTH DIVISION-MULTIPLEXING AND SUBCARRIER-MULTIPLEXING (WDM-SCM) TRANSMISSION USING FIBER BRILLOUIN AMPLIFICATION
(1992-08-01)
LEE, YH
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WU, J
;
KAO, MS
;
TSAO, HW
;
電信工程研究所
A subcarrier multiplexing based optical wavelength division multiplexing system with fibre Brillouin amplification (FBA) is analysed. In the optical domain, a pump laser is tuned to amplify the corresponding optical carrier by FBA for the desired group of SCM signals. In the electrical domain, a microwave tuner is used to select the desired channel in the selected SCM group. This system has the benefits of eliminating the need for polarisation control, the ability to cancel phase noise due to the 'squaring' photodetection process of the selected optical carrier together with its SCM channels, and enhancement of optical receiver sensitivity by amplification of the carrier. Comparisons with other systems are also presented.
PERFORMANCE DEGRADATION DUE TO POLARIZATION MODE DISPERSION IN A COHERENT OPTICAL-SYSTEM WITH PILOT CARRIER
(1991-03-01)
KAO, MS
;
WU, JS
;
電信工程研究所
;
Institute of Communications Engineering
The use of pilot carrier in a coherent optical communication system can simplify the receiver; however, the polarization mode dispersion caused by fiber birefringence may degrade the system performance. Here we use the formulation of principal states of polarization and provide a simple expression to evaluate the performance degradation.
PERFORMANCE EVALUATION OF COHERENT SUBCARRIER MULTIPLEXED OPTICAL-DISTRIBUTION SYSTEMS WITH COMMON LOCAL OSCILLATORS
(1991-08-01)
KAO, MS
;
WU, J
;
電信工程研究所
;
Institute of Communications Engineering
Coherent subcarrier multiplexed local distribution systems using a common local oscillator (LO) in which the LO is provided by a distribution centre instead of locally generated at the subscriber premise are described. Both single and multiple optical carrier systems are considered. Because of the low path loss in a local optical network, a common LO system is possible with a LO shared by many subscribers, and indeed provides many advantages. First, a simplified receiver is achievable which eliminates a tunable LO, an automatic frequency control (AFC) circuit, a polarisation controller, and an optical coupler. Secondly, the system cost is decreased due to the reduction of components. Thirdly, laser phase noise and intermediate frequency (IF) drift are expected to be minimised. Fourthly, because no active optical components are placed at the subscriber premises, the system reliability is increased. Fifthly, the common LO system can be expanded with optical amplifiers without increasing the number of LO and simultaneous amplification of the message, and LO signals are achievable. By sharing high power, highly frequency stabilised, and very narrow linewidth LO lasers provided by the centre, it is expected that a simple and reliable coherent optical distributing network can be constructed by using common LO.
WDM CODING FOR HIGH-CAPACITY LIGHTWAVE SYSTEMS
(1994-01-01)
SHAO, SK
;
KAO, MS
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電信工程研究所
;
電信研究中心
;
Institute of Communications Engineering
An interchannel parallel coding scheme in the wavelength domain-the WDM coding system-is proposed. The system differs from the usual serial coding systems and provides many advantages. First, data channels are completely unaltered in the coding process, rendering it very suitable for practical lightwave systems with standard bit rate. Second, parallel encoding/decoding systems are simpler than those of serial coding systems, being easier to be implemented in high-speed optical systems. Third, compared with serial coding, WDM coding is able to reduce heavily the number of encoding/decoding pairs. For example, a (15, 11) Hamming coded WDM system reduces the number from 12 x 11 = 132 to 1 at the line rate of STS-12. Fourth, the WDM coding system could offer infinite coding gain in dispersion-limited lightwave systems. Finally, WDM coding systems could correct single-channel burst error. The system performance was evaluated and the system limitation imposed by bit-skew among wavelength channels was analyzed. The results indicated that a 15-channel Hamming coded WDM system can reduce the uncoded BER from 10(-9) to 3 x 10(-17) and the distance limitation imposed by bit-skew is 250 km if a dispersion-shifted fiber is used and a channel span of 30 nm is assumed
WDM CODING SYSTEM WITH SINGLE PARITY-CHECK CHANNEL
(1994-10-01)
KAO, MS
;
SHAO, SK
;
CHEN, HY
;
電信工程研究所
;
電信研究中心
We propose a modified WDM coding system with a single parity-check channel to achieve an efficient and flexible WDM coding system. The system provides most of the advantages of the original WDM coding system with just one parity-check channel. The bit rate and the data sequences are unaffected by the coding processes, making it very attractive for practical lightwave systems with standard rates. Compared to serial coding systems, it is able to reduce the number of encoding/decoding pairs in an m-channel WDM transmission system operated at STS-N from m x N to one. We have evaluated the system performance and analyzed the performance of frame synchronization needed for the modified WDM coding system. An example shows that the WDM coding can reduce the error floor of a four-channel dispersion-limited WDM system from 10(-10) to 10(-19) with reliable frame synchronization.