Browsing by Author "Liaw, SK"

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A self-frequency-locked multi-wavelength erbium-doped fibre ring laser
(1996-10-01)
Liaw, SK
;
Wang, ACL
;
Liaw, JW
;
Chi, S
;
光電工程學系
A self-frequency-locked laser in a 1.55 mu m band is demonstrated by adding a segment of samarium-doped fibre (SDF) into an erbium-doped fibre (EDF) ring laser cavity. The narrow band output signal, with a 3 dB down line width of less than 0.15 nm and a side-mode suppression ratio larger than 30 dB, is nearly polarization independent. A multi-wavelength EDF ring lasersource, using a 1 x n synchronous optical switch and n segments of SDF with different lengths, is proposed.
Demultiplexer crosstalk rejection requirements for hybrid WDM system with analog and digital channels
(1998-05-01)
Ho, KP
;
Liaw, SK
;
光電工程學系
;
Department of Photonics
Hybrid WDM systems with both analog and digital channels are a natural choice for the video transmission applications. The effects of crosstalk in a hybrid WDM system are measured and analyzed in this letter. The required crosstalk rejection ratio is also provided with the assumption that the differences in received optical power among various channels are the same as their differences in receiver sensitivities.
Dynamic power-equalized EDFA module based on strain tunable fiber Bragg gratings
(1999-07-01)
Liaw, SK
;
Ho, KP
;
Chi, S
;
光電工程學系
;
Department of Photonics
An adaptive power-equalized erbium-doped fiber amplifier (EDFA) module is proposed and experimentally demonstrated by using strain tunable fiber Bragg gratings (FBG's), In a demonstration for a five-channel wavelength-division-multiplexed (WDM) system, the EDFA module can effectively reduce the power variation from II dB to 0.3 db, Measured power penalty for 2.5-Gb/s data is less than 0.5 and 1.1 dB for 5 and 17 dB of signal attenuation by tunable FBG's, respectively. The power-equalized EDFA module can find wide applications in WDM lightwave transmission systems.
Dynamically selective multiwavelength cross-connect based on fibre Bragg gratings and mechanical optical switches
(1998-02-01)
Chen, YK
;
Liaw, SK
;
Lee, CC
;
光電工程研究所
;
Institute of EO Enginerring
A dynamically selective multiwavelength cross-connect for wavelength division multiplexed (WDM) networks based on fibre Bragg gratings (FBGs) and optical switches is reported. Dynamically single-or multi-channel cross-connect functionality can be realized according to control of the optical switches and the FBGs' arrangement. Bit-error-rate performance with negligible power penalty is achieved in a 2.5 Gb s(-1) x 3 WDM channels over 100 km conventional single-mode fibre (SMF) network demonstration. The characteristics of low channel crosstalk, uniform channel loss, high scalability and cascadability, and low cost of this device could provide more reconfiguration flexibility and network survivability for WDM networks.
Dynamically selective multiwavelength cross-connect based on fibre Bragg gratings and mechanical optical switches
(1998-02-01)
Chen, YK
;
Liaw, SK
;
Lee, CC
;
光電工程學系
;
Department of Photonics
A dynamically selective multiwavelength cross-connect for wavelength division multiplexed (WDM) networks based on fibre Bragg gratings (FBGs) and optical switches is reported. Dynamically single-or multi-channel cross-connect functionality can be realized according to control of the optical switches and the FBGs' arrangement. Bit-error-rate performance with negligible power penalty is achieved in a 2.5 Gb s(-1) x 3 WDM channels over 100 km conventional single-mode fibre (SMF) network demonstration. The characteristics of low channel crosstalk, uniform channel loss, high scalability and cascadability, and low cost of this device could provide more reconfiguration flexibility and network survivability for WDM networks.
Eight-channel bidirectional WDM add/drop multiplexer
(1998-05-14)
Ho, KP
;
Liaw, SK
;
光電工程學系
;
Department of Photonics
The authors propose and demonstrate an eight-channel reconfigurable bidirectional wavelength division multiplexed (WDM) add-drop multiplexer in which all channels can be added/dropped independently in either direction. The performance of the bidirectional WDM add/drop multiplexer is experimentally studied for a data rate of 10Gbit/s per channel, providing an overall capacity of 80Gbit/s. It is found that the performance of the add/drop multiplexer is not degraded by a backward propagating signal.
Experimental investigation of a fiber Bragg grating integrated optical limiting amplifier with high dynamic range
(1998-07-01)
Liaw, SK
;
Chi, S
;
光電工程學系
;
Department of Photonics
By inserting a bidirectional erbium-doped fiber amplifier (EDFA) in between an optical circulator and a fiber Bragg grating (FBG), we realize an FBG-integrated optical limiting amplifier (OLA) with high dynamic range. The dual-pass OLA has a wide dynamic range of over 40 dB and a saturation signal output power of about 13.0 dBm. The performance of dual-pass OLA has no obvious degradation due to back reflection of the amplified signal. A negligible power penalty of about 0.3 dB is observed when compared with other conventional configurations. The FBG-integrated OLA configuration has potential application in wavelength division multiplexing (WDM) systems where high saturated power is needed for multichannel transmission. (C) 1998 Society of Photo-Optical Instrumentation Engineers.
Experimental investigation of wavelength-tunable WADM and OXC devices using strain-tunable fiber Bragg gratings
(1999-10-01)
Liaw, SK
;
Ho, KP
;
Lin, CL
;
Chi, S
;
光電工程學系
Two reconfigurable wavelength add/drop multiplexer (WADM) and optical cross-connect (OXC) devices based on strain-tunable fiber Bragg gratings (ST-FBGs) are proposed. The feasibility of WADM is verified by measuring the bit-error-rate performance of the dropped (cross-connect) and pass-through (no cross-connect) channels over a 50- and 100-km standard single-mode fiber for a 2.5 Gb/s system. Compared to back-to-back transmission, a negligible power penalty of only 0.2 dB is observed. (C) 1999 Published by Elsevier Science B.V. All rights reserved.
Externally-modulated high-power fiber grating ring laser for digital transmission
(1998-11-01)
Liaw, SK
;
Ho, KP
;
Chi, S
;
光電工程研究所
;
Institute of EO Enginerring
We have constructed a low-cost, double-cavity erbium-doped fiber ring laser with a fiber Bragg grating and a 2 x 2 coupler. A high output power of 8.7 dBm and a signal-to-noise-floor ratio of 43 dB were demonstrated. This fiber grating ring laser is used as the light source for the 2.488 Gb/s transmission experiment through a 100 km single mode fiber. To our knowledge, this is the first time a fiber grating ring laser is being used as an externally modulated source for digital transmission. (C) 1998 Elsevier Science Ltd. All rights reserved.
Externally-modulated high-power fiber grating ring laser for digital transmission
(1998-11-01)
Liaw, SK
;
Ho, KP
;
Chi, S
;
光電工程學系
;
Department of Photonics
We have constructed a low-cost, double-cavity erbium-doped fiber ring laser with a fiber Bragg grating and a 2 x 2 coupler. A high output power of 8.7 dBm and a signal-to-noise-floor ratio of 43 dB were demonstrated. This fiber grating ring laser is used as the light source for the 2.488 Gb/s transmission experiment through a 100 km single mode fiber. To our knowledge, this is the first time a fiber grating ring laser is being used as an externally modulated source for digital transmission. (C) 1998 Elsevier Science Ltd. All rights reserved.
Fiber-grating-based optical limiting amplifier module for dual-wavelength, hybrid data rate transmission
(2000)
Liaw, SK
;
Chi, S
;
Tseng, HY
;
光電工程學系
;
Department of Photonics
A multichannel fiber-grating-based optical limiting amplifier module is proposed Dual-wavelength, hybrid data rate transmission is demonstrated with 30 dB input dynamic range. For 5.0 and 25 Gbit/s dual-channel transmission in a 200 km single-mode fiber, power penalty due to gain competition between channels and backreflection noise is less than 0.6 dB compared to the receiver sensitivity of 0 km, 5.0 Gbit/s single-channel operation.
Gain-flattened optical limiting amplifier modules for wavelength division multiplexing transmission
(1999)
Liaw, SK
;
Chi, S
;
光電工程學系
;
Department of Photonics
By integration of a bidirectional erbium-doped fiber amplifier and a three-port optical circulator with several fiber Bragg gratings (FBGs), two gain-flattened optical limiting amplifier (OLA) modules are proposed and experimentally demonstrated. They rely on the use of central wavelength misalignment and bending loss methods, respectively. They cart effectively cover the whole useful 1.55-mu m band. Both modules can provide gain-flattening characteristics over a large input dynamic range. The FBGs-integrated OLA configuration has potential application in wavelength division multiplexing lightwave communication systems.
High-dynamic-range optical cross-connect device using fiber Bragg gratings
(1999-08-01)
Liaw, SK
;
Ho, KP
;
Chen, LK
;
Tong, F
;
Chi, S
Using in optical networks; a reconfigurable and low-cost 2 x 2 optical cross-connect device based on fiber Bragg gratings and optical limiting amplifiers is investigated and demonstrated. The input dynamic range is over 20 dB for both crossing and passing channels. Small power penalty of 0.6-1.0 dB is found for a two-channel 2.5 Gb/s over a 100-km system demonstration.
Hybrid wavelength-division-multiplexing systems for high-capacity digital and analog video trunking applications
(1998-02-01)
Ho, KP
;
Dai, HX
;
Lin, CL
;
Liaw, SK
;
Gysel, H
A five-channel hybrid wavelength-division-multiplexing (WDM) system with one AM-VSB channel and four 2.5-Gb/s channels was demonstrated for video trunking and distribution applications, Two erbium-doped fiber amplifiers (EDFA's) with saturated output power of +13 dBm were used for a standard single mode fiber span of 100 km, Error-free transmission for the digital channels and a carrier-to-noise ratio (CNR) higher than 50 dB for the AM-VSB channel could be achieved simultaneously.
Hybrid wavelength-division-multiplexing systems for high-capacity digital and analog video trunking applications
(1998-02-01)
Ho, KP
;
Dai, HX
;
Lin, CL
;
Liaw, SK
;
Gysel, H
A five-channel hybrid wavelength-division-multiplexing (WDM) system with one AM-VSB channel and four 2.5-Gb/s channels was demonstrated for video trunking and distribution applications, Two erbium-doped fiber amplifiers (EDFA's) with saturated output power of +13 dBm were used for a standard single mode fiber span of 100 km, Error-free transmission for the digital channels and a carrier-to-noise ratio (CNR) higher than 50 dB for the AM-VSB channel could be achieved simultaneously.
Multichannel add/drop and cross-connect using fibre Bragg gratings and optical switches
(1998-08-06)
Liaw, SK
;
Ho, KP
;
Chi, S
;
光電工程學系
;
Department of Photonics
A dynamically selective wavelength add/drop multiplexer (WADM) and a multiwavelength cross-connect (M-XC) configuration for dense wavelength division multiplexed networks are proposed. Multiple channels add/drop and/or cross-connect can be realised according to the control of the optical switches and fibre Bragg gratings arrangement. The selective WADM and M-XC devices could provide more reconfigurable flexibility and survivability in WDM networks.
Multichannel bidirectional transmission using a WDM MUX/DMUX pair and unidirectional in-line amplifiers
(1997-12-01)
Liaw, SK
;
Ho, KP
;
Lin, CL
;
Chi, S
;
光電工程研究所
We propose a repeated bidirectional WDM transmission system using cascaded WDM MUX/DMUX pairs as narrow-bandpass filters and reflection attenuators, Fiber span is increased by inserting unidirectional EDFA's between WDM MUX/DMUX pair as in-line amplifiers. A three channel hybrid system with one 10-Gb/s and two 2.5-Gb/s channels is also demonstrated in the 1550-nm region for transmission over 150 km of dispersion-shifted fiber, Negligible power penalty due to back reflection was observed.
Multichannel bidirectional transmission using a WDM MUX/DMUX pair and unidirectional in-line amplifiers
(1997-12-01)
Liaw, SK
;
Ho, KP
;
Lin, CL
;
Chi, S
;
光電工程學系
We propose a repeated bidirectional WDM transmission system using cascaded WDM MUX/DMUX pairs as narrow-bandpass filters and reflection attenuators, Fiber span is increased by inserting unidirectional EDFA's between WDM MUX/DMUX pair as in-line amplifiers. A three channel hybrid system with one 10-Gb/s and two 2.5-Gb/s channels is also demonstrated in the 1550-nm region for transmission over 150 km of dispersion-shifted fiber, Negligible power penalty due to back reflection was observed.
Optimum gain-equalised configuration of wideband erbium-doped fibre amplifier using inter-stage samarium-doped fibre and midway isolator
(1996-11-07)
Chen, YK
;
Liaw, SK
;
光電工程學系
;
Department of Photonics
The optimum gain-equalised configuration for the erbium-doped fibre amplifier (EDFA) using a samarium-doped fibre (SDF) is investigated. The dual-pumping scheme with inter-stage SDF and midway isolator was found to be the optimum scheme for obtaining flattened high spectral gain with variation of less than or equal to +/-0.7dB and with a low noise figure of less than or equal to 5.6dB within the 1530-1560nm range. This amplifier is suitable for multiwavelength transmission systems containing EDFA cascades.
Parallel pump-shared linear cavity laser array using 980-nm pump reflectors or N pieces of gain fibers as self-equalizers
(2000-01-01)
Liaw, SK
;
Tseng, HY
;
Chi, S
;
光電工程學系
;
Department of Photonics
By using fiber gratings as pump reflectors with various reflectivities or N pieces of gain fibers with various lengths externally to linear cavity as self-equalizers, a parallel-type, pump-shared linear cavity laser array (LCLA) is proposed and numerically studied, The average output power is increased and the maximum power variation among channels is reduced from 7.2 to less than 0.1 dB when the reflectivity of each pump reflector or the length of each gain fiber is adjusted appropriately.