Browsing by Author "Chien-Chung"

Now showing 1 - 5 of 5

All-optical 2R regenerator using self-seeded laser diode
(2009-04-14)
Chi
;
Sien
;
Lee
;
Chien-Chung
;
Chien
The present invention is a self-seeded laser diode. The laser diode obtains a gain by itself without using expansive erbium-doped fiber amplifiers. Hence, the cost is reduced and the system is simplified.
Fast wavelength-tunable laser system using Fabry-Perot laser diode
(2006-04-11)
Chi
;
Sien
;
Lee
;
Chien-Chung
;
Yeh
The invention relates to a laser system using a multi-longitudinal-mode Fabry-Perot laser diode as an inter-injection light source and a gain cavity formed by other laser diodes of such type so as to achieve the function of fast wavelength switching, so that it is possible to achieve repetitively fast switching of wavelength by varying and controlling the bias voltage of maximum optical gain in said inter-injection type multi-longitudinal-mode Fabry-Perot laser diode so as to achieve three different wavelengths with tuning range of 3.5 nm for a side-mode suppression ratio (SMSR) greater than 19 dB and a response time of wavelength switching in the order of nanosecond.
Method of enhancing spatial resolution for distributed temperature measurement
(2004-11-16)
Chi
;
Sien
;
Lee
;
Chien-Chung
;
Chiang
A method that utilizes a short sampling interval and a long-pulsewidth laser source to obtain the long sensing range and employs a signal processing technique of decomposing Brillouin spectrum to achieve high spatial resolution, high temperature resolution of the distributed temperature measurement is disclosed. The present method includes the steps of measuring the Brillouin spectra of an optical pulse applying to a sensing fiber and a overlapped area thereof, determining the length that the pulse enters according to the measured Brillouin spectra and a weighting factor and then determining a real Brillouin spectrum profile and a temperature distribution according to Brillouin frequency shifts thereof. For a 9500-m sensing range of standard single-mode fiber and a 100-ns pulsewidth laser source, spatial and positon resolutions of 20 cm and a temperature resolution of 1.degree. C. are simultaneously achieved by using this signal processing method.
Method of utilizing a fiber for simultaneously measuring distributed strain and temperature
(2004-03-02)
Chi
;
Sien
;
Lee
;
Chien-Chung
;
Chiang
A method that utilizes a dispersion-shifted fiber having compound compositions with different temperature coefficients in core to simultaneously measure the distributed strain and temperature based on Brillouin frequency shift is disclosed. The present method includes the steps of obtaining mean two peak frequencies in a multi-peak Brillouin spectrum of the dispersion-shifted fiber, determining a temperature change according to the formula of a Brillouin frequency shift of the peak relating to strain and temperature conditions of the fiber, and determining a strain change through the formula. In a 3682-m sensing length of Large-Effective-Area NZ-DS fiber, a temperature resolution of 5.degree. C., a strain resolution of 60 .mu..epsilon. and a spatial resolution of 2 m are achieve simultaneously.
Optical monitoring apparatus for use in wavelength division multiplexing network
(2006-03-07)
Chi
;
Sien
;
Lee
;
Chien-Chung
;
Yeh
An optical monitoring apparatus based on the scanning of the gain profile of erbium-doped fiber amplifiers (EDFA) and applied in a wavelength division multiplexing network has been proposed and experimentally demonstrated. The EDFA with an injected saturated tone can provide variable gain or loss profile by controlling the pump power. The components used in the present optical monitoring apparatus for use in a wavelength division multiplexing network are easily available and cost-effective, valuable for monitoring frequency and power of a WDM optical communication system, and capable of greatly enhancing resolution of monitoring frequency spectrum for the optical fiber network system.