Specialty optical fibers for Raman lasers

Abstract

As described in the preceding chapters, the performances of Raman fiber lasers and amplifiers are governed by the parameters (including Raman gain coefficients, Raman shift, transmission window and loss, damage threshold, chemical and thermal stability, etc.) of optical fibers. At present, over 1 ĸW 1 μm Raman lasers based on silica fibers have been demonstrated by several esteemed groups. Widely tunable Raman lasers from 1 to 2 μm were reported in silica fibers. However, silica fibers are not suitable for constructing mid-infrared (MIR) fiber lasers and amplifiers (>2.5 μm) because of very high material loss in the mid-infrared spectral region. To solve this problem, several types of specialty optical fibers (SOFs) based on fluoride, tellurite, and chalcogenide glasses with low transmission loss in mid-infrared region have been developed. This chapter deals with the optical properties of such fibers, the related Raman fiber lasers and amplifiers. The parameters of those SOFs are described in Sect. 5.1. Section 5.2 focuses on design and construction of Raman laser and amplifiers based on those SOFs. Section 5.3 concentrates on the generation of MIR Raman soliton lasers in those SOFs.