Browsing by Author "CHIEN, PY"

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2-FREQUENCY DISPLACEMENT MEASUREMENT INTERFEROMETER BASED ON A DOUBLE-HETERODYNE TECHNIQUE
(1991-01-01)
CHIEN, PY
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
;
Department of Photonics
A two-frequency laser heterodyne interferometer has been implemented for small displacement measurement. The displacement signal is detected by using a double-heterodyne technique. Vibration amplitudes at 1 kHz on the order of 1 nm and smaller can be detected.
2-FREQUENCY FIBEROPTIC SENSOR SYSTEM USING HIGH-BIREFRINGENCE OPTICAL FIBER
(1992-04-01)
CHIEN, PY
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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
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 LASER INTERFEROMETER BASED ON THE FREQUENCY-DIVISION-MODULATED LASER DIODE SOURCES
(1991-11-01)
CHIEN, PY
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
;
Department of Photonics
A two-wavelength interferometer based on the frequency-division-modulated laser diodes has been demonstrated. By employing this technique, the frequency difference between two laser diodes has been stabilized to less than 3.0 x 10(-9) and the synthetic heterodyne signal is also generated for measuring the optical phase shift absolutely.
A BALANCED DUAL-PHOTODETECTOR OPTICAL RECEIVER FOR DAYLIGHT OPERATION
(1991-04-01)
CHIEN, PY
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交大名義發表
;
光電工程學系
;
National Chiao Tung University
;
Department of Photonics
A balanced dual-photodetector optical receiver with an active optical feedback circuit suitable for daylight operation has been developed. This receiver is suitable for laser range finder or fuse systems operating under high level of sunlight illumination. The design and operation of the receiver is discussed.
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
;
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
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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 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.
A TIMING STABILIZED LASER DIODE BASED RANGE SIMULATOR
(1991-05-01)
CHIEN, PY
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交大名義發表
;
光電工程學系
;
National Chiao Tung University
;
Department of Photonics
A timing stabilized laser diode based range simulator has been demonstrated. Range simulation is achieved by locking the time delay between the reference signal generator and the time base of the output light pulse using a double phase-lock-loop. Phase stabilization to within 1.0 x 10(-5) rad Hz-1/2 has been implemented within the range - pi to + pi rad.
AN ACTIVE FIBEROPTIC INTERFEROMETRIC SENSOR BASED ON A LOW FINESSE FIBEROPTIC FABRY-PEROT
(1991-10-01)
CHIEN, PY
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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 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
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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
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PAN, CL
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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.
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
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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
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PAN, RP
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PAN, CL
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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.
FIBEROPTIC GYROSCOPES BASED ON POLARIZATION SCRAMBLING
(1991-02-01)
CHIEN, PY
;
PAN, CL
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交大名義發表
;
光電工程學系
;
National Chiao Tung University
A novel fiber-optic gyroscope with a single-mode diode laser as the light source and two polarization scramblers as time-varying depolarizers is demonstrated. This arrangement reduces the nonreciprocal phase noise induced by the cross coupling between polarization modes in single-mode fibers. The experimental results show that a phase-noise reduction factor of 18 can be achieved.
FREQUENCY STABILIZATION OF LASER-DIODES AT 0.83 MU-M USING A FIBER OPTIC COUPLER
(1990-05-01)
CHIEN, PY
;
PAN, CL
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光電工程學系
;
電信研究中心
;
Department of Photonics
MULTIPLEXED FIBEROPTIC SENSORS USING A DUAL-SLOPE FREQUENCY-MODULATED SOURCE
(1991-06-01)
CHIEN, PY
;
PAN, CL
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
We propose and demonstrate a multiplexed fiber-optic sensor system using a dual-slope (triangular) frequency-modulated laser source. The restrictions in the selection of beat frequencies of the multiplexed sensors in previous studies that employed ramp modulation wave forms are eliminated.
OPEN-LOOP FIBER OPTIC GYROSCOPE WITH WIDE DYNAMIC-RANGE
(1992-07-01)
CHIEN, PY
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
;
Department of Photonics
An open-loop, wide dynamic range, fiber optic gyroscope has been demonstrated by using the PLL phase tracking technique. This technique provides a linear output of an open-loop gyroscope with the Sagnac phase shift up to 2N-pi-rad, N=2n, is where n an integer number.
RELATIVE FREQUENCY STABILIZATION OF A SET OF LASER-DIODES USING THE TIME-GATING TECHNIQUE
(1991-05-15)
CHIEN, PY
;
PAN, CL
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
We have demonstrated experimentally the relative frequency stabilization of a set of laser diodes using the time-gating technique. The frequencies of three single-mode laser diodes (lambda = 0.83-mu-m) have been stabilized within the free spectral range (FSR) of a Fabry-Perot interferometer with fixed frequency spacing.
SCALE-FACTOR-STABILIZED FIBEROPTIC GYROSCOPE BASED ON A SPECTRUM-BROADENED LASER-DIODE SOURCE
(1991-03-15)
CHIEN, PY
;
PAN, CL
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
A spectrum-broadened laser-diode source that uses the optical feedback and current-modulation effects has been adopted as the light source of a fiber-optic gyroscope to reduce the inherent phase noise. The scale factor of the gyroscope has also been stabilized.