Yeon Wan Koh

Harmonically mode-locked fiber laser with an acousto-optic modulator in a Sagnac loop and Faraday rotating mirror cavity

Abstract We have demonstrated a new scheme of harmonically mode-locked fiber laser utilizing an all-fiber acousto-optic modulator, which is composed of a two-mode fiber, as an active mode-locker. The harmonically mode-locked lasing occurs when a harmonic frequency of the modulator driven frequency matches with one of the harmonics of the cavity modes at the least common multiple frequency value. The mode-locked laser pulses were obtained at the 7th harmonics of the cavitys fundamental mode frequency.

An electronically wavelength-tunable mode-locked fiber laser using an all-fiber acoustooptic tunable filter

We have demonstrated a novel scheme of a continuously wavelength-tunable and passively mode-locked fiber laser by using the sliding frequency effect of an all-fiber acoustooptic tunable filter. Stable and nearly transform-limited pulses of 800-fs pulsewidth were produced with this laser scheme for a wavelength tuning range of 17 nm at around 1550 nm.We have demonstrated a novel scheme of a continuously wavelength-tunable and passively mode-locked fiber laser by using the sliding frequency effect of an all-fiber acoustooptic tunable filter. Stable and nearly transform-limited pulses of 800-fs pulsewidth were produced with this laser scheme for a wavelength tuning range of 17 nm at around 1550 nm.

Strain effects on two-mode fiber gratings.

The spectral, interferometric, and polarization properties of mode-coupling fiber gratings under strain are described. The grating is formed by photosensitivity that uses modal interference in the two-mode fiber. Theoretical and experimental results show the possibilities of using the fiber grating for optical switches, tunable filters, interferometric sensors, and polarizers.

Analysis of polarization properties of a mode-locked fiber laser gyroscope

We investigated the polarization characteristics of a mode-locked fiber laser gyroscope (MLPLG) formed with a Nd-doped fiber as an optical gain medium and a Sagnac loop mirror. The output pulse patterns and the polarization states were found to be determined by fiber birefringence in the different sections of the MLPLG. We describe the conditions for the MLPLG to operate with automatic reciprocity leading to the possibility of phase-error-free operation.