• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.905-906
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• 2013

• Korean Journal of Optics and Photonics
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• v.18 no.5
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• pp.317-322
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• 2007

We performed injection-locking by two independent semiconductor lasers and investigated the spectral modes of the injection-locked laser From the observation of the saturated absorption spectrum in the $^{85}Rb$ D1 transition line, we have confirmed that the frequency of the injection-locked slave laser is synchronized by the frequency of the master laser, and the slave laser has a narrow linewidth after injection-locking. According to the intensity injected into the slave laser, we measured the variation of the injection-locking range and the mode of the injection-locked slave laser by using the confocal Fabry-Ferret interferometer. In the case of the incomplete injection-locking, we observed the competition between the free running mode of the slave laser and the mode of the master laser and analyzed the modes of the injection-locked slave laser.

• Journal of the Optical Society of Korea
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• v.19 no.2
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• pp.130-135
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• 2015

Based on the extended nonlinear Schr$\ddot{o}$dinger equation, the influences of the filter effect on pulse splitting in a passively mode-locked erbium-doped fiber laser with positive dispersion cavity are investigated theoretically. Numerical results show that, as the bandwidth of the spectral filter decreases, the nonlinear chirp appended to the pulse increases under the combined action of the filter effect of the super-Gaussian spectral filter and the self-phase modulation effect. On further decreasing the bandwidth, the wave breaking of the pulse takes place. In addition, by varying the pump power of the laser or the profile of the spectral filter, the influences of the filter effect on pulse splitting also change accordingly.

• Journal of the Optical Society of Korea
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• v.17 no.2
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• pp.177-181
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• 2013

We present an all-fiberized power-scalable, sub-nanosecond mode-locked laser based on a frequency-shifted-feedback ring cavity comprised of an erbium-doped fiber, a downshifting acousto-optic modulator (AOM), and a bandpass filter (BPF). With the aid of the frequency-shifted feedback mechanism provided by the AOM and the narrow filter bandwidth of 0.45 nm, we generate self-starting, mode-locked optical pulses with a spectral bandwidth of ~0.098 nm and a pulsewidth of 432 to 536 ps. In particular, the output power is readily scalable with pump power while keeping the temporal shape and spectral bandwidth. This is obtained via the consolidation of bound pulse modes circulating at the fundamental repetition rate of the cavity. In fact, the consolidated pulses form a single-entity envelope of asymmetric Gaussian shape where no discrete internal pulses are perceived. This result highlights that the inclusion of the narrow BPF into the cavity is crucial to achieving the consolidated pulses.

• ETRI Journal
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• v.18 no.1
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• pp.1-14
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• 1996

We have experimentally observed and theoretically analyzed the gain dependent optimum repetition rates of a hybrid-type active and passive mode locked laser pulses in an erbium-doped fiber laser of the figure-of-eight geometry by utilizing a nonlinear amplifier loop mirror (NALM) as a saturable absorber and a directional-coupler type electro-optic modulator as an active mode locker. Transform-limited mode-locked pulses of about 10 ps width were obtained at repetition rates which correspond to harmonics of the cavity fundamental frequency and depend on the optical amplifier gain in the NALM.

• Journal of the Optical Society of Korea
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• v.15 no.1
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• pp.56-60
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• 2011

We demonstrate passive mode-locking of a Cr:forsterite laser with a single-walled carbon nanotube saturable absorber mirror (SWCNT-SAM). Without compensation of intra-cavity dispersion, the self-mode-locked laser generates 11.7 ps pulses at a repetition rate of 86 MHz. The dispersion-compensated laser yields ultrashort pulses as short as 80 fs near $1.25\;{\mu}m$ at 78 MHz with average output powers up to 295 mW, representing the highest power ever reported for mode-locked solid-state lasers based on saturable absorption of SWCNTs in this spectral region.

• Korean Journal of Optics and Photonics
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• v.11 no.5
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• pp.353-359
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• 2000

A harmonically mode-locked fiber ring laser cavlty was theoretically analyzed. The measured charactenstlcs of a 10 GHz erbium-doped fiber ring laser were used as a basis of the theoretical analysis. From the nonlinear Schroedinger equation of an actively mode-locked erblUm-doped fiber laser. the effects of the components inside the laser cavity have been analyzed includmg nonlinear effects from group-velocity dispersion (GVD) and self-phase modulation (SPM). Usmg the analysls. we have designed a laser cavity with minimum pulsewidth and chirp by changing the intracavity optical intensity and the bandwidth of the filter. In the new design, the chirp i, reduced by 2 times and the pulsewidth by 2A times. compared to the laser used in the experiment. iment.

• Korean Journal of Optics and Photonics
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• v.1 no.2
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• pp.185-190
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• 1990

Balanced CPM ring dye laser was fabricated. Pulses as short as 62 fs were measured using noncollinear second harmonic generation autocorrelator. The optimum conditions were studied by changing the concentration of staturable absorber, pumping power of Ar+ laser and alignments of the intracavity four-prism sequence.

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.204-205
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• 2003

We demonstrate a novel OFDR system with compactness and short measurement time based on the use of a wavelength-swept mode-locked fiber laser. The optical source uses an intra-cavity tunable Fabry-Perot filter as a tuning element. The fiber laser sweeps 20 nm in less than 10 ms. Spatial resolution of 100 fm and total measurement range of several centimeters are demonstrate

• Korean Journal of Optics and Photonics
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• v.2 no.4
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• pp.197-202
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• 1991

The real time autocorrelator has been developed in order to measure the pulse widths of ultrashort laser pulses using the SHG method. The scanning range of the autocorrelator is 142 ps, and inserting a delay block in one arm of the autocorrelator, the scanning range can be extended to 250 ps. The shortest pulse width was measured to be 20 ps, when the cavity length was well matched to the RF frequency of the mode-locker, and broadened to be 39 ps and 47 ps as the cavity length was detuned.