Abstract

The cascaded Raman fiber laser is a proven technology that provides wavelength agile high-power fiber lasers outside the rare-earth emission windows. However, conventional cascaded Raman fiber lasers lack wavelength agility due to the use of fixed wavelength fiber Bragg gratings. Recently, proposed cascaded Raman fiber lasers based on random distributed feedback have provided a grating-free solution enabling wavelength agility. With these lasers, wide wavelength tunability has been achieved. However, there are still limitations in scaling output power while maintaining high spectral purity of wavelength conversion. Spectral purity is characterized by the in-band power ratio, which is the ratio of the output power in the required wavelength to the total power. The origin of this limitation arises from the inability to efficiently terminate the Raman cascade at a specific wavelength with increasing power. In this Letter, we propose a novel filtered distributed feedback mechanism to terminate the Raman cascade at any desired wavelength, enabling power scaling with high spectral purity. Output power up to 28 W has been achieved with $>85\%$ in-band power ratio and $>400\mathrm{nm}$ tuning range from 1118 to 1535 nm.

© 2019 Optical Society of America

High-power, cascaded random Raman fiber laser with near complete conversion over wide wavelength and power tuning

V. Balaswamy, Siddharth Ramachandran, and V. R. Supradeepa
Opt. Express 27(7) 9725-9732 (2019)

High-power, fixed, and tunable wavelength, grating-free cascaded Raman fiber lasers

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Cascaded Raman fiber lasers with ultrahigh spectral purity

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All-fiberized cascaded random Raman fiber laser with high spectral purity based on filtering feedback

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Random Raman fiber laser based on a twin-core fiber with FBGs inscribed by femtosecond radiation

M. I. Skvortsov, S. R. Abdullina, A. A. Wolf, A. V. Dostovalov, A. A. Vlasov, I. A. Lobach, S. Wabnitz, and S. A. Babin
Opt. Lett. 44(2) 295-298 (2019)