All-fiber passively Q-switched fiber lasers

Year: 2011

Pavel Peterka, Ph.D.

Fiber lasers are one of the most spectacular achievements of modern optics and laser physics. Applications of fiber lasers are versatile, ranging from lasers of brute force for industrial cutting and welding to delicate devices currently being developed for the most precise measurement of time and frequency. The researchers in UFE have been investigating novel types of all-fiber pulsed laser in Q-switched regime of operation. In collaboration with researchers from the University of Nice in France we have shown that a chromium-doped fiber stabilizes an otherwise spontaneously chaotically self-pulsing ytterbium-doped fiber laser. This original passively Q-switched all-fiber laser produces sustained and relatively stable trains of smooth pulses at a high repetition rate [5]. In addition, we have proposed an all-fiber Q-switched fiber laser in which the optical switch exploits an interplay between resonant nonlinearity of a section of ytterbium-doped fiber and transmission of a combination of fiber gratings [6]. Both types of these fiber lasers may find applications in various fields, e.g. in fiber lasers for material processing or in medical laser systems. In the course of the research of the pulsed fiber laser we have observed a spectacular effect of the periodic drift of the laser line in a wide range of almost 10 nm and time period of about 2 s. It is the first published observation of the effect that is now known as self-induced laser line sweeping (SLLS) in fiber lasers [7]. Although the SLLS is an undesired effect in ytterbium-doped fibre lasers intended for the continuous mode of operation, this effect may find useful applications, e.g., in interrogation of optical fiber sensor systems.

Wavelength self-sweeping observed in free-running fibre lasers.

1. Dussardier, B. – Maria, J. – Peterka, P.: Passively Q-switched ytterbium- and chromium-doped all-fiber laser, Applied Optics Vol. 50 (2011), E20-E23.
2. Dussardier, B. – Blanc, W. – Peterka, P.:"Tailoring of the local environment of active ions in rare-earth- and transition-metal-doped optical fibres, and potential applications", book chapter in Selected topics on optical fiber technology, editors M. Yasin, S. W. Harun, and H. Arof, InTech, Croatia, February 2012.
3. Peterka, P. – Honzátko, P. – Slavík, R.: "Celovláknový laser s pasivním Q-spínáním", přihláška vynálezu č. PV 2011-362, 17. června 2011.
4. Peterka, P. – Maria, J. – Dussardier, B. – Slavik, R. – Honzatko, P. – Kubecek V.: "Long-period fiber grating as wavelength selective element in double-clad Yb-doped fiber-ring lasers", Laser Phys. Lett. Vol. 6, (2009), 732-736.
5. P. Peterka, P. Navrátil, J. Maria, B. Dussardier, R. Slavík, P. Honzátko, and V. Kubeček, "Self-induced laser line sweeping in double-clad Yb-doped fiber-ring lasers", Laser Phys. Lett. 9, 445-450 (2012).