Browsing by Author "Hsueh, PS"

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Optically injection mode-locked 1.3 mu m semiconductor optical amplifier fiber ring laser by using gain-switching single-mode FPLD
(2002)
Hsueh, PS
;
Lee, SK
;
Lin, GR
;
光電工程學系
;
Department of Photonics
We demonstrate a novel approach for generating a stable and low polarization-sensitive mode-locked fiber ring laser by using a low-cost Fabry-Perot laser diode (FPLD) as both the intracavity mode-locker and the band-pass filter. The FPLD pulses is seeded into a close-loop semiconductor optical amplifier (SOA) based fiber ring laser for harmonic and rational harmonic mode-locking operation. The SOA biased at 65 mA and 18degreesC combines with an intracavity optically feedback-injected 1.3 mum FPLD biased at 9.4 mA (below threshold current) and 23degreesC via some optical couplers. Picosecond optical pulse with side-mode suppressing ratio of greater than 12 dB are obtained, the measured lindwidth at 3-dB and 10-dB decay are observed to maintain at about 0.04 nm and 0.14 nm, respectively. Narrow-linewidth operation of the SOAFL with optical pulsewidth of 42.1 ps and wavelength tuning range of about 10 nm at repetition rate of 13 GHz has been demonstrated. The optically injection mode-locking scheme also has shown to exhibit low supermode noise, higher average output power and good stability. The optical output power under harmonic mode-locked scheme is about 297 muW. The fluctuation in output power, the SSB phase noise at 1 kHz offset frequency, and the calculated rms timing jitter within the integral region from 0 Hz to 1 KHz are +/-2.5 muW, -82.4 dBc/Hz, and 1.0 ps, respectively.
Spectral characteristics of a regenerative semiconductor optical amplifier mutually injection locked with a Fabry-Perot laser diode
(2004-01-01)
Lin, GR
;
Hsueh, PS
;
光電工程學系
;
Department of Photonics
The anomalous injection locking of a traveling-wave semiconductor optical amplifier (SOA) and a fiber-pigtailed Fabry-Perot laser diode (FPLD) linked with single-mode and improved side-mode suppression ratio output is demonstrated. We achieve this injection locking by driving the FPLD slightly below threshold and by feedback injecting the FPLD with fractional output of a closed-loop SOA. The SOA-FPLD link lases in a single FPLD longitudinal mode with a reduced linewidth of 0.013 nm and a maximum side-mode-suppressing ratio of 39.7 dB. A precise 3-dB linewidth of 45-50 MHz is also observed from the self-homodyne mode-beating spectrum. The optimized feedback-injecting power for the FPLD is similar to2% of the SOA-FPLD linked output power of >400 muW. The variations in output power and in peak wavelength are not more than 0.54% and 0.06%, respectively. The injection-locked SOA-FPLD link is insensitive to the temperature fluctuation within +/-0.25degreesC. (C) 2004 Optical Society of America.
The detuning characteristics of rational harmonic mode-locked semiconductor optical amplifier fiber-ring laser using backward optical sinusoidal-wave injection modulation
(2005-03-01)
Lin, GR
;
Hsueh, PS
;
Wu, HH
;
Liao, YS
;
光電工程學系
The modulation waveform, power, and frequency detuning dynamics of a semiconductor optical amplifier fiber-ring laser (SOAFL) harmonic and rational-harmonic mode-locked by using backward injection of a large-signal sinusoidal-wave modulated Fabry-Perot laser diode (FPLD) are studied. The shortest pulsewidth of 53.3 ps at 1 GHz with spectral linewidth of 0.09 run at modulation power of 17 dBm can be obtained, which corresponds to a time-bandwidth product of 2.8. The threshold modulation power and the maximum frequency detuning range for harmonic mode-locking of the SOAFL are 11.5 dBm and 180 kHz, respectively. The mode-locked SOAFL gradually recovers back to sinusoidal-wave modulation mode at the detuning frequency beyond +/- 400 kHz. The pulse broadening slopes for the positive- and negative-frequency detuning regions of 0.48 and 0.375 ps/kHz are,determined, respectively. By enlarging the modulating power and detuning the modulation frequency of FPLD, the SOAFL can be rational-harmonic mode-locked up to 12 GHz with 33-ps pulsewidth.