Browsing by Author "Cheng, BC"

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Broadband C- plus L-band double-ring fiber baser based on a two-stage hybrid amplifier
(2005-10-01)
Yeh, CH
;
Cheng, BC
;
Chen, CY
;
Chi, S
;
光電工程學系
A stable and wavelength-tunable C- plus L-band fiber double-ring laser, which uses a two-stage hybrid amplifier with a semiconductor optical amplifier and an erbium-cloped fiber amplifier, has been proposed and experimentally demonstrated. Based on the double-ring configuration, the proposed fiber ring laser exhibits more stable output wavelengths and powers than the single-ring laser. A wide tunable range of 1540 to 1620 nm, a side-mode suppression ratio (SMSR) of > 31.2 dB/0.05 nm over a wide tuning range from 1550 to 1612 nm, and an output power of > 2 dBm over the operation range of 1546 to 1608 nm have been achieved. (c) 2005 Society of Photo-Optical Instrumentation Engineers.
Dynamics of an ultracold cascade three-level atom interacting with a two-mode cavity field
(2002-02-01)
Zhang, ZM
;
Chi, S
;
Cheng, BC
;
光電工程學系
;
Department of Photonics
The interaction between an ultracold cascade three-level atom and a two-mode cavity field has been studied. The effects of the centre-of-mass motion, the cavity length, the coupling constants, the initial field states and the initial field intensity on the atomic dynamics have been examined. We have found that the population probabilities show dependence on the interaction time in the fast-atom region while they show dependence on the interaction length in the slow-atom region. The variations of the probabilities versus the cavity length show resonant peaks, and the peaks become sharper as the atom moves more slowly. The coupling constants, the initial field states and the initial field intensity also influence the atomic dynamics significantly. The two transitions are competitive for the atomic probability in the middle state, while they are cooperative for that in the lower state.
Self-induced transparency with transverse variations in resonant media by the power series approximation method
(2005-01-01)
Cheng, BC
;
Tseng, HY
;
Chi, S
;
光電工程研究所
;
Institute of EO Enginerring
This paper presents the analytic solutions of self-induced transparency with transverse variations in resonant media by a self-consistent power series approximation method. We solve the Maxwell-Bloch equations by retaining all integral terms from the inhomogeneous broadening and the second-derivative terms with respect to distance and time. The lowest-order approximation is presented in detail. We discuss the characteristics of the distortionless pulses that propagate in an inhomogeneously broadening medium. It is shown that the group velocity and peak power of the self-induced transparency solitons could be represented in terms of the pulse width, the angle between phase velocity and group velocity, and the basic material parameters of the resonant medium. The chirping of the soliton is also discussed.
Stabilized single-frequency fiber ring laser based on hybrid amplifier and fiber Fabry-Perot devices for C- plus L-band operation
(2005-10-01)
Yeh, CH
;
Cheng, BC
;
Chen, CY
;
Chi, S
;
光電工程學系
Using optical Fabry-Perot devices for a wavelength-tunable S-band erbium-doped fiber ring laser with single-frequency operation
(2005-10-01)
Yeh, CH
;
Chien, HC
;
Cheng, BC
;
Lee, CC
;
Chi, S
We have proposed and experimentally demonstrated a stabilized and tunable S-band erbium-doped fiber ring laser by using a Fabry-Perot laser diode (FPLD) and a fiber Fabry-Perot filter inside the ring cavity. Due to the bandwidth limitation of the FPLD, the effective operating range of the proposed laser is confined to 1490.28 to 1521.22 nm with a tuning step of 0.08 nm. A side-mode suppression ratio of > 39.1 dB at 0.05 nm and an output power of > 0.4 dBm can be achieved while this laser is tuned from 1490.28 to 1510.27 nm. Zero output wavelength variation and output power fluctuation <= 0.03 dB have also been obtained. (c) 2005 Society of Photo-Optical Instrumentation Engineers.