Browsing by Author "KUO, JC"

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BIREFRINGENCE-INDUCED SPECTRAL FEATURES IN CONTINUOUS-WAVE AND PASSIVELY MODE-LOCKED TI-SAPPHIRE LASERS
(1992-11-01)
PAN, CL
;
HWANG, CD
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KUO, JC
;
SHIEH, JM
;
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
;
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
;
CHANG, CS
;
PAN, CL
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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
;
交大名義發表
;
電信研究中心
;
National Chiao Tung University
EFFECT OF DYE CONCENTRATION ON PICOSECOND AND FEMTOSECOND CW PASSIVELY MODE-LOCKED TI-SAPPHIRE DDI LASERS
(1992-10-15)
PAN, CL
;
HWANG, CD
;
KUO, JC
;
SHIEH, JM
;
WU, KH
The role of the saturable absorber dye DDI in the cw passively mode-locked Ti:sapphire/DDI laser both with and without compensation prisms is investigated. This laser self-starts when the concentration of the dye is greater than almost-equal-to 2 X 10(-4) M for both picosecond and femtosecond pulses. With the prism pair, the laser generates Gaussian pulses 150 fs in duration. The corresponding spectrum is sech2 in shape with a FWHM of 8 nm. These parameters are independent of the DDI concentration. Without the prism pair, the laser generates picosecond pulses with the FWHM decreasing from 8 to 3 ps as the dye concentration is increased from 2.5 x 10(-4) to 1 X 10(-3) M. Concurrently the pulse shape changes from a Lorentzian to a nearly symmetric two-sided exponential shape. The picosecond spectra for different dye concentrations are also presented.
PULSE BUILDUP DYNAMICS OF AN ACTIVELY MODE-LOCKED LASER-DIODE ARRAY IN THE EXTERNAL-CAVITY
(1995-03-01)
WANG, CL
;
KUO, JC
;
CHANG, CS
;
PAN, CL
;
交大名義發表
Dynamic pulse evolution characteristics of an actively mode-locked laser diode array in the external cavity have been investigated, Numerical calculations based on modified traveling-wave rate equations reproduce experimentally observed pulse and spectral width evolution and show that the buildup time is about 45 round-trips, We have also performed a theoretical analysis to understand which of the laser operating parameters would affect the buildup dynamics, It is shown that either higher de bias current or larger radiative recombination coefficient (which is inversely proportional to the excited-state lifetime) will render the laser exhibiting shorter steady-state pulse width and faster evolution to the steady state, Other parameters affecting the buildup, but to a lesser extent, include the radio-frequency (RF) modulation current, spontaneous emission coefficient, and gain coefficient, The power reflectivities of the output mirror and the antireflection coated diode facet, on the other hand, have little effect on the pulse width and buildup time for single pulse generation.
PULSE-FORMING DYNAMICS OF A CW PASSIVELY MODE-LOCKED TI-SAPPHIRE DDI LASER
(1992-03-01)
KUO, JC
;
SHIEH, JM
;
HWANG, CD
;
CHANG, CS
;
PAN, CL
The dynamics of pulse formation in a cw passively mode-locked Ti:sapphire/DDI laser has been investigated. It is found that the time required for the circulating energy in the cavity to build up and bleach the dye absorber is approximately 140-mu-s. A further 230-mu-s is required for the buildup of steady-state picosecond pulses. Concurrently the laser output spectrum initially narrows in the cw regime, begins to broaden as the laser becomes modulated, and finally establishes the steady-state spectral distribution.
TRANSIENT CONJUGATED HEAT-TRANSFER IN FULLY-DEVELOPED LAMINAR PIPE FLOWS
(1988-05-01)
LIN, TF
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KUO, JC
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交大名義發表
;
機械工程學系
;
National Chiao Tung University