Browsing by Author "PAN, CL"

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2-FREQUENCY FIBEROPTIC SENSOR SYSTEM USING HIGH-BIREFRINGENCE OPTICAL FIBER
(1992-04-01)
CHIEN, PY
;
PAN, CL
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
A fiber sensor system based on high-birefringence optical fiber and a frequency-stabilized He-Ne Zeeman laser (lambda = 0.6328-mu-m) has been demonstrated. The small path-length changes of interest are extracted from the amplitude or phase of the laser beat frequency by using either the phase-sensitive detection or the phase-demodulation technique. A minimum detectable optical phase delay of 1.5 x 10(-6) rad/Hz1/2 or 17 x 10(-6) rad/Hz1/2 has been achieved.
2-WAVELENGTH INTERFEROMETER BASES ON A 2-COLOR LASER-DIODE ARRAY AND THE 2ND-ORDER CORRELATION TECHNIQUE
(1995-05-01)
WANG, CL
;
CHUANG, YH
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PAN, CL
;
交大名義發表
;
光電工程學系
A novel two-wavelength interferometer is demonstrated that uses a tunable two-color laser-diode array as the light source. The synthetic wavelength can be easily tuned from 2 to 0.043 mm by variation of the spectral separation between the two wavelengths of the laser output. By using the second-order correlation technique we can directly retrieve the phase change at the synthetic wavelength with no need for sophisticated electronic signal processing.
A COMPARATIVE-STUDY OF 2 TYPES OF FEEDBACK LOOP FOR STABILIZATION OF THE SCALE FACTOR IN OPEN-LOOP FIBEROPTIC GYROSCOPES
(1991-10-01)
CHIEN, PY
;
PAN, CL
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交大名義發表
;
光電工程學系
;
National Chiao Tung University
An open-loop fibre-optic gyroscope with stabilized scale factor has been constructed with a spectrum-broadened laser diode as the light source. A comparative study of two types of servo loop for scale factor stabilization showed that the automatic gain control (AGC) loop is superior to the automatic power control (APC) loop.
A NOVEL OPTOELECTRONIC PHASE-LOCKED LOOP BASED ON A SQUARE-WAVE PHASE-MODULATED STATIC FIBEROPTIC GYROSCOPE
(1992-12-15)
PAN, CL
;
CHIEN, PY
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
We propose and demonstrate a novel optoelectronic phase-locked loop (OEPLL). The key element of the OEPLL is an electro-optic harmonic mixer consisting of a square-wave phase-modulated static fiber-optic gyroscope (FOG) with an intensity-modulated laser diode as the light source. As a first demonstration, we have phase-locked a target electronic oscillator modulating the laser diode at the 10th harmonic frequency of the reference oscillator which modulates the phase of the FOG.
A QUANTITATIVE STUDY OF THE FAR-FIELD LASER-INDUCED RING PATTERN FROM NEMATIC LIQUID-CRYSTAL FILMS
(1992-08-01)
PAN, RP
;
CHEN, SM
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PAN, CL
;
電子物理學系
;
光電工程學系
We report the first detailed measurement of multiple (up to twenty) diffraction rings due to a laser beam traversing a nematic liquid crystal cell. Experimental measured intensity distributions are in good agreements with numerical calculations based on the diffraction theory, taking into account the spatial self-phase modulation effect, the two-dimensionality of the problem, the wavefront curvature effect and the non-local response of the nematic liquid crystals. The individual contributions of the aforementioned effects on the far-field pattern are clearly illustrated.
A SIMPLE METHOD FOR SINGLE-FREQUENCY OPERATION AND AMPLITUDE-STABILIZATION AND FREQUENCY-STABILIZATION OF AN INTERNAL-MIRROR HE-NE-LASER
(1985)
PAN, CL
;
KUO, CC
;
HSIEH, TC
;
LEI, TF
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交大名義發表
A THERMAL PHASE-LOCKED LOOP FOR FREQUENCY STABILIZATION OF INTERNAL-MIRROR HE-NE LASERS (LAMBDA=0.633 MU-M)
(1991-04-01)
CHIEN, PY
;
PAN, CL
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
A new servo circuit based on the thermal phase-locked loop (TPLL) has been developed for frequency stabilization of internal-mirror He-Ne laser. A feedback signal proportional to the fluctuation in the frequency of the laser is down-converted through a voltage-controlled oscillator (VCO) and compared in a phase/frequency circuit with that of a frequency reference. The detected phase difference then drives a heater wrapped around the laser tube for tuning the laser cavity length. The frequency stability achieved is +/- 1.0 x 10(-9) over a period of several hours.
AN ACTIVE FIBEROPTIC INTERFEROMETRIC SENSOR BASED ON A LOW FINESSE FIBEROPTIC FABRY-PEROT
(1991-10-01)
CHIEN, PY
;
PAN, CL
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
We demonstrate a novel active fibre-optic interferometric sensor based on a temperature-stabilized low-finesse fibre-optic Fabry-Perot. In this apparatus, information on the optical phase was extracted from the frequency shift of the He-Ne laser of which the cavity length was thermally tuned to compensate change in the interference signal. It is shown that an improvement in the stability of the interference signal by two orders of magnitudes can be realized. The tracking achievable between the Fabry-Perot interferometer and the laser was better than 1 part in 10(8). That is, the relative frequency stability of the laser was less-than-or-equal-to 1.0 x 10(-8) over an interval of tens of minutes. Detection of a change of 5 nm in the optical path length of the fibre-optic Fabry-Perot was also demonstrated. The dynamic range of this interferometer is over 40 dB and the linearity characteristics are excellent. These performance characteristics were limited by the long-term thermal drift of the apparatus, not the low reflectivity of the fibre ends of the Fabry-Perot interferometer.
AN ALL-FIBER FREQUENCY STABILIZER TO A SET OF LASER-DIODES BASED ON DOUBLE FIBER RESONATORS
(1991-11-15)
CHIEN, PY
;
PAN, CL
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
A relative frequency statilization technique, using double fiber resonators as the frequency discriminator, has been demonstrated. By employing the frequency-division-multiplexing technique (FDM) to the laser diodes, the frequency offset between the tested laser diodes has been stabilized to DELTA-nu/nu less-than-or-equal-to 3.0 x 10(-9).
AN OPTICAL SIGNAL GENERATOR BASED ON A TRIANGULARLY PHASE-MODULATED INTERFEROMETER
(1991-10-01)
CHIEN, PY
;
PAN, CL
;
光電工程學系
;
電信研究中心
;
Department of Photonics
We demonstrated a novel optical signal generator by applying a triangular phase-modulation waveform to a laser diode interferometer. Frequency-multiplied (up to eight hundred times of the modulation signal) output in the format of an optical signal could be generated. By changing the amplitude of the triangular waveform, we can tune the frequency of the optical signal. This system can thus be considered a voltage-controlled oscillator (VCO) with an optical output signal.
ATOMIC-ABSORPTION SPECTRA INDUCED BY NARB IN SODIUM-RUBIDIUM VAPOR
(1989-05-01)
LU, MH
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CHEN, WM
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PAN, CL
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交大名義發表
;
光電工程學系
BIREFRINGENCE-INDUCED SPECTRAL FEATURES IN CONTINUOUS-WAVE AND PASSIVELY MODE-LOCKED TI-SAPPHIRE LASERS
(1992-11-01)
PAN, CL
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HWANG, CD
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KUO, JC
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SHIEH, JM
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WU, KH
We show that the transient spectrum of a continuous-wave Ti:sapphire laser during the initial stage of the buildup, which exhibits multiple clusters (of longitudinal modes), is due to the spectral windowing effect of the Brewster-angle-cut Ti:sapphire crystal, which acts as a birefringent filter in the laser cavity. This effect is also responsible for certain spectral features of a passively mode-locked Ti:sapphire/DDI laser.
BUILDUP DYNAMICS OF THE SPECTRUM AND THE AVERAGE OUTPUT POWER OF A HOMOGENEOUSLY BROADENED CONTINUOUS-WAVE TI-SAPPHIRE LASER
(1992-07-15)
PAN, CL
;
KUO, JC
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HWANG, CD
;
SHIEH, JM
;
LAI, Y
The buildup dynamics of a homogeneously broadened continuous-wave Ti:sapphire laser is experimentally investigated for the first time to our knowledge. The average output power of the laser exhibits relaxation oscillation behavior initially and approaches the steady-state value in almost-equal-to 20-mu-s. Concurrently, the longitudinal-mode spectrum evolves from a multicluster spectral distribution (tentatively attributed to the spectral windowing effect of the Brewster-angle-cut Ti:sapphire crystal as a birefringent filter) to a single cluster at 787.5 nm. The spectral narrowing (which is due to gain competition in the homogeneously broadened medium), however, takes almost-equal-to 500-mu-s. Physical mechanisms that explain qualitatively the two distinctive time scales are presented.
BUILDUP OF STEADY-STATE PICOSECOND PULSES IN AN ACTIVELY MODE-LOCKED LASER-DIODE ARRAY
(1991-09-01)
KUO, JC
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CHANG, CS
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PAN, CL
;
交大名義發表
;
光電工程學系
We have studied experimentally the temporal and spectral characteristics of an actively mode-locked laser-diode array in an external cavity as it evolves to the steady state. It is found that the buildup time to steady-state picosecond pulses takes less than 45 round trips. The number of clusters of the longitudinal-mode spectrum reduces during the evolution and finally approaches a steady-state spectral distribution with the pulse energy mainly distributed among a few clusters near the line center.
BUILDUP OF STEADY-STATE SUBPICOSECOND AND FEMTOSECOND PULSES IN A COLLIDING-PULSE MODE-LOCKED RING DYE-LASER
(1990-11-15)
KUO, JC
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PAN, CL
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交大名義發表
;
電信研究中心
;
National Chiao Tung University
COMPLETELY SELF-STARTING PICOSECOND AND FEMTOSECOND KERR-LENS MODE-LOCKED TI-SAPPHIRE LASER
(1995-05-01)
SHIEH, JM
;
GANIKHANOV, F
;
LIN, KH
;
HSIEH, WF
;
PAN, CL
Completely self-starting and stable operation of a Kerr-lens mode-locked Ti:sapphire laser was realized in both picosecond and femtosecond regimes. The cavity has a symmetric X configuration with soft aperturing. Enhanced Kerr nonlinearity and reduced backscattering effects were thought to be key to obtaining stable self-starting self-mode-locked operation from 765 to 815 nm far the picosecond regime and from 770 to 835 nm for the femtosecond regime. The mode-locking starting time as measured by the onset of the second-harmonic signal ranged from 300 ms to 2 s, depending on cavity alignment. Preliminary data also suggest that intracavity intensity fluctuation necessary for the laser to evolve into stable mode locking could be as short as 10-40 ps.
DEEP PHASE-MODULATION APPROACH TO AN OPEN-LOOP FIBER OPTIC GYROSCOPE
(1991-03-01)
CHIEN, PY
;
PAN, CL
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
A new approach to an open-loop, all-fiber gyroscope with wide dynamic range and linear scale factor is described. For signal processing, the Sagnac phase lift is converted into a phase shift in the low-frequency electrical signal by using a deep sinusoidal phase-modulation waveform followed by gate-switching. With the duty cycle of the gating signal selected to be in the range between 20 and 70%, the scale factor is stable with respect to change in the amplitude of the phase modulation signal by as much as 15%. The basic principle of this technique and experimental results are reported.
DEMONSTRATION OF A NOVEL WIDE-BAND OPTICAL SIGNAL GENERATOR BY DEEP PHASE MODULATION IN A FIBER COUPLER
(1991-06-01)
CHIEN, PY
;
PAN, CL
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
A simple method for wide bandwidth optical signal generation has been realized by applying a deep phase modulation signal in a fiber coupler which acts as an all-fiber Michelson interferometer. The output of the interferometer displays a discrete spectrum with a nearly leveled output and frequency bandwidth up to a hundred times that of the frequency of the modulation signal. In this first demonstration, we have generated frequency components up to 4 MHz (with external modulation) and 50 MHz (by direct modulation of the laser diode) respectively. Multigigahertz operation is possible in the future with wideband integrated-optic phase modulators.
DOUBLE PHASE MODULATION APPROACH TO AN INTERFEROMETRIC SYSTEM
(1992-09-15)
CHIEN, PY
;
PAN, RP
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PAN, CL
;
交大名義發表
;
光電工程學系
A novel method for measuring the phase difference between interfering beams in an interferometric system is demonstrated by using a double phase modulation technique. There are two modulation signals applied to the interferometric system. The first modulation signal is used to modulate the path length for pseudo-heterodyne processing. The second modulation signal is used to modulate the frequency of the laser diode for equivalent wavelength synthesis. This approach is demonstrated by using a fiberoptic Mach-Zehnder interferometer.
DUAL-WAVELENGTH ACTIVELY MODE-LOCKED LASER-DIODE ARRAY WITH AN EXTERNAL GRATING-LOADED CAVITY
(1994-09-15)
WANG, CL
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PAN, CL
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交大名義發表
;
光電工程學系
;
National Chiao Tung University
We report the generation of dual-wavelength picosecond pulses by use of a commercial laser-diode array. The laser cavity incorporated a folded dispersive delay line with a V-shaped double-stripe mirror. The spectral separation of the laser output at the two wavelengths can be tuned from 2 to 11 nm. The actively mode-locked pulse widths at the two wavelengths were both 29 ps. Cross-correlation and power-spectrum measurements indicated that the two-color pulses were synchronized with an absolute timing jitter of less than 1 ps (instrument limited).