Development of compact femtosecond fiber laser and alignment free confocal system for multilayered optical memory

We developed a compact and high-power mode-locked fiber laser for three-dimensional optical memory. Fiber lasers have the potential to be compact and stable light sources that can replace bulk solid-state lasers. To generate high-power pulses, we used stretched-pulse mode locking. The average power and pulse width of the output pulse from the fiber laser that we developed were 109 mW and 2.1 ps, respectively. The dispersion of the output pulse was compensated with an external single-mode fiber of 2.5 m length. The pulse was compressed from 2.1 ps to 93 fs by dispersion compensation. The pulse emitted from this fiber laser has a sufficient energy to generate two-photon recording effectively, so the fiber laser we have developed is possible to use as a light source of three-dimensional optical memory. We also propose an all-fiber recording and readout system for multilayered memories.