Ultrashort Fiber Laser Research Articles

自相似超短脉冲光纤激光器研究进展

自相似超短脉冲光纤激光器研究进展

Polarization-maintaining, high-energy, wavelength-tunable, Er-doped ultrashort pulse fiber laser using carbon-nanotube polyimide film

A high-energy, wavelength-tunable, all-polarization-maintaining Er-doped ultrashort fiber laser was demonstrated using a polyimide film dispersed with single-wall carbon nanotubes. A variable output coupler and wavelength filter were used in the cavity configuration, and high-power operation was demonstrated. The maximum average power was 12.6 mW and pulse energy was 585 pJ for stable single-pulse operation with an output coupling ratio as high as 98.3%. Wide wavelength-tunable operation at 1532-1562 nm was also demonstrated by controlling the wavelength filter. The RF amplitude noise characteristics were examined in terms of their dependence on output coupling ratio and oscillation wavelength.

Chirped Bragg Grating Waveguides Directly Written Inside Fused Silica Glass With an Externally Modulated Ultrashort Fiber Laser

A modulated fiber laser provided burst-trains of femtosecond pulses to directly write linearly chirped Bragg grating waveguides inside bulk fused silica glass in a single process step. The results represent the first demonstration of chirped gratings embedded in bulk glass with an ultrafast laser. Simple exposure controls offer facile means for tuning spectral and dispersion responses in three-dimensional optical circuits.

High Precision Frequency Standards Using Mode-Locked Fiber Lasers

We describe an application of ultrashort fiber lasers to high precision frequency standards that enable us to measure unknown optical frequencies directly. Mode-locked lasers have a unique feature in that there are neatly repetitive longitudinal modes in the output pulses, which form an optical comb. Therefore, if we can stabilize the comb separation, which is a longitudinal mode separation, we can use such a comb as an extremely precise “optical measure”. In this paper, we describe two kinds of frequency standard application of mode-locked fiber lasers. One is passive mode locking which has a fine and long comb. However, it is difficult to extract one of the optical combs. The other is active mode locking which has a coarse and short comb. Nevertheless, it is advantageous in that it makes it possible to extract one of the standard combs with an optical filter and transmit it through an optical network. Finally, a cesium (Cs) optical atomic clock is described as an application to a new frequency standard.