• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.7
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• pp.1393-1397
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• 2009

A high-speed wavelength swept laser, which is based on oscillation characteristics of a fiber Fabry-Perot tunable filter, is described. The laser is constructed by using a semiconductor optical amplifier, a fiber Fabry-Perot tunable filter, and 3.348 km fiber ring cavity. The wavelength sweeps are repeatatively generated with the repetition period of 61 kHz which is the first parallel oscillation frequency of the Fabry-Perot tunable filter for the low power consumption. Mode-locking is implemented by 3.348 km fiber ring cavity for matching the fundamental of cavity roundtrip time to the sweep period. The wavelength tuning range of the laser is 87 nm(FWHM) and the average output power is 1.284 mW.

• Korean Journal of Optics and Photonics
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• v.11 no.3
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• pp.166-170
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• 2000

A wavelength tunable all-optical clock recovery using a semiconductor optical amplifier in a fiber ring cavity is proposed and demonstrated at the wavelength of 1530 nm to 1570 nm. A synchronized optical pulse train is recovered from 10 Gbps and 30 Gbps randomly generated optical pulse streams with injection locking technique. Also, the system responses to the perturbation and the input average power variation are analyzed by a large-signal model based on time-domain travelling wave equation. ation.

• Korean Journal of Optics and Photonics
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• v.18 no.3
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• pp.216-220
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• 2007

A widely tunable add/drop filter composed of double ring resonators is implemented with high-index-contrast polymer waveguide. To enhance the productivity, directional couplers are designed to have good fabrication tolerance. The refractive indices of the core and cladding in the 1550 nm wavelength are 1.51 and 1.378, respectively. Drop response in comparison with neighborhood peak gets enhanced by more than 2.9 dB at the wavelength where both rings resonate. This filter can be used to build widely tunable laser diode through hybrid-integration with reflective SOA.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.419-423
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• 2003

In this paper, we have constructed singly resonant KTP OPO system pumped by 532 nm to obtain broadly frequency tunable pulses. Also we have mathematically simulated frequency tuning range, phase matching angle for 900 nm output and threshold energy, and we calculated output intensity using wave propagation equations for optical parametric oscillator which include walk-off, pump depletion.

• Korean Journal of Optics and Photonics
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• v.22 no.4
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• pp.179-183
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• 2011

An external cavity laser operating at near infrared wavelength is demonstrated by incorporating polymer waveguide Bragg reflectors. 3rd order Bragg grating and oversized rip waveguide structure were designed by using the effective index method and the transmission matrix method. The polymer waveguide was fabricated using polymer materials with refractive indices of 1.462 and 1.435 for the core and the cladding layers, respectively. The external feedback laser with 875-nm Bragg grating exhibits single mode lasing located at 850-nm wavelength with an output power of 0 dBm, a 20-dB bandwidth of 0.2 nm and a side mode suppression ratio of 40 dB.

• Korean Journal of Optics and Photonics
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• v.18 no.1
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• pp.66-73
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• 2007

The various output characteristics of a pulsed Ti:sapphire laser oscillator with a plane-parallel resonator, pumped longitudinally by the second harmonic wave of a Nd:YAG laser, and the output of a Ti:sapphire laser amplifier operated along the single path of the oscillator beam were investigated and analyzed. In the case of the oscillator, we measured the spectrum, the pulse buildup time, the temporal duration time of the pulse, and the output energy according to the variation of the pumping energy, resonator length, and the reflectance of the output coupler. And, in the case of the amplifier, we investigated and analyzed the output energy of the amplifier as a function of the time difference between the two pump beams of the oscillator and the amplifier, the pumping energy of the oscillator, and the pumping energy of the amplifier When pump energies of both the oscillator and the amplifier were 18 mJ/pulse, we could find that the output energy of the amplifier increased linearly and gradually up to the time difference of 35 ns. Finally, we determined that the slope efficiencies of the oscillator and the amplifier were 23.5 % and 11.6 %, respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.439-441
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• 2012

A new wavelength tunable laser source based on a self-seeded F-P LD for a WDM-PON system has been proposed in this paper. The proposed laser source has a merit of the wavelength tunable range of approximately 20 nm with very simple setup. The measured minimum relative intensity noise(RIN) was approximately -124 dB/Hz and the possibility of 10 Gb/s external modulation was showed.

• Korean Journal of Optics and Photonics
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• v.15 no.5
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• pp.455-460
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• 2004

We have developed a mode-locked ultra-short pulse C $r^{4+}$:YAG laser, as well as a continuous wave C $r^{4+}$:YAG laser. The laser was pumped by a Nd:YAG laser and its characteristics were investigated. In continuous wave mode, we obtained as much as 600 mW at 1.436 ${\mu}{\textrm}{m}$ with pumping power of 6 W, by using an output coupler with a reflectivity of 98%. The power slope efficiency was 10%, when the gain medium was cooled to 19$^{\circ}C$. The tuning range was varied from 1.39 ${\mu}{\textrm}{m}$ to 1.55 ${\mu}{\textrm}{m}$ and the maximum power was 400 mW at 1.492 ${\mu}{\textrm}{m}$ with a 3-plate birefringent filter. The C $r^{4+}$:YAG laser was mode-locked by a Kerr lens mode locking method. Mode locking at 1.436 ${\mu}{\textrm}{m}$was initiated by slightly rocking a mirror mount. But the pulses were very unstable because of the strong water absorption at this region. So we shifted the lasing wavelength to 1.492 ${\mu}{\textrm}{m}$ by using a 3-plate birefringent filter. Then we obtained stable state mode-locking with the maximum average power of 280 mW for a pumping power of 6 W. The pulse width of 43 fs was measured using an autocorrelator and the repetition rate was 104.5 MHz.

• Korean Journal of Optics and Photonics
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• v.10 no.2
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• pp.162-168
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• 1999

A new design of four-pass dye laser amplifier affording a narrow-bandwidth pulsed output is demonstrated to suppress the amplified spontaneous emission(ASE) carried by the amplifier output and reduce the possibility of parasitic oscillation in the amplifier. By the direct pulsed amplification of a cw 100 mW dye laser under a Q-switched doubled Nd:YAG laser pumping with energy of 5.6 mJ/pulse, high-peak-power pulsed output with 1.5-mJ energy in 130-MHz bandwidth is obtained corresponding to a power gain greater than $2{\times}10^6$ and an energy efficiency of 27%. The ASE ratio in the four-pass amplifier output is dramatically reduced by using a diffraction grating in the amplifier. Compared with the results obtained from the normal operation of the amplifier with no frequency-selective device, the ASE ratio is reduced by a factor in excess of 10 to remain under 1.5% of the amplifier output whereas the total output energy is slightly increased by ~4%.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.62-63
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• 2002

파장가변 색소 레이저 발진기는 반사형 회절격자에 비스듬히 입사하는 Grazing Incidence형 공진기 구조로 설계되었다.[1-2] 색소용액이 고속으로 순환되는 색소 셀에 여기광인 레이저 광원을 입사시키는 방법은 색소 셀과 색소 용액 순환방향 및 펌핑 광의 방향이 서로 수직을 이루도록 구성되어 있다. 또한, 두 개의 펌핑 광을 양방향에서 동시에 입사시킬 수 있도록 함으로써, 색소 셀 내부의 색소 용액이 여기 광을 균일하게 흡수하도록 설계하였다. (중략)