CC BY
2The 30th International Conference on Advanced Laser Technologies
ALT'23
LS-O-3
Infrared random laser based on artificial Rayleigh fiber
D.V. Ryakhovskii1, S.M. Popov1 A.A. Rybaltovskii23, Yu. K. Chamorovskii2, O.V. Butov2
1- Kotelnikov Institute of Radioengineering and Electronics of RAS, Vvedensky Sq. 1, 141190 Fryazino, Russia 2- Kotelnikov Institute of Radioengineering and Electronics of RAS, Mokhovaya 11-7 St,125009 Moscow, Russia 3- Prokhorov General Physics Institute of the RAS, Vavilova 38 St., 119333 Moscow, Russia
dryh9 [email protected]
Optical fibers (OF) have their application in various fields of science and technology. In addition to the use of optical fibers in information systems (communication lines and fiber sensors), the use of optical fibers in laser systems is also developing. A new direction in the development of laser systems has become the so-called. "Random lasers" [1-2]. This direction has become a subject of great interest for researchers around the world due to the ability of random fiber lasers to generate light with unique performance characteristics without imposing strict requirements on the optical cavity. In such lasers, amplification is achieved due to the effects of Raman scattering [1] or SBS [2]. Due to the fact that the Rayleigh scattering coefficient is extremely small (it provides reflection), in such random lasers the cavity length is usually 10-100 km for SMF-28 type OF. New development trends are associated with the transition to lasers with a cavity based on short (5 -20 meters) artificial Rayleigh OF [3] (OFs containing an array of fiber Bragg gratings - FBGs) incribed during drawing process. This article is devoted the evolution of our previous works, including an optimization of random laser cavities, based on artificial Rayleigh fiber and adapted to the telecom conventional wavelength range (also known as "C-band" range). The main novelty is the development of artificial Rayleigh fiber on the basis of a special photosensitive Er-doped OF with a germanophosphosilicate core matrix.
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Distance, mm
200
-604— 1500
1520 1540 1560 1580 Wavelength, nm
1600
Fig. 1. Laser cavity structure - left. Laser emission spectrum at pumping on 976 nm (30 mW) - right.
The lasing cavity structure investigated by OFDR technique is shown in Fig 1 (left). The FBGs inscription contrast (excess of the return signal over the Rayleigh level) is 43 dB. The length of the laser's cavity is 6 meters (600 FBGs). The phase mask period is 1070 nm. Core/cladding diameter - 5/125 ^m. OF's cutoff wavelength is 900 nm. The laser has a half-opened cavity extended by the wavelength-matched 90% FBG. The emission spectrum obtained under 976 nm "backward"-pumping is shown in Fig. 1 (right). The laser has a 1548 nm single emission peak and a slope efficiency of 33%. The operation mode is continuous-wave like showed previously [3]. The linewidth measured by self-heterodyne technique is less 1 kHz. These random fiber lasers can operate continuously at room temperature for a long time (at least tens of minutes), which is extremely important from the point of view of the prospects for its use as a compact source of high coherence optical radiation.
The work was carried out within the framework of the Kotelnikov IRE RAS state task. The work of A.A.R. is supported by RSF №22-19-00511 in part of producing preforms.
[1] S. Turitsyn, S. Babin, A. El-Taher, et al., Random distributed feedback fibre laser, Nature Photonics V.4, pp. 231-235 (2010).
[2] A. Fotiadi, An incoherent fibre laser, Nature Photonics 4, pp. 204-205 (2010).
[3] S.M. Popov, et al., Random lasing in a short Er-doped artificial Rayleigh fiber, Results in Physics 16, 102868 (2020).
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