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Optical Fibers and Accessories
Published in Daniel Malacara-Hernández, Brian J. Thompson, Advanced Optical Instruments and Techniques, 2017
A section of birefringent fiber can also act as a high-order waveplate if both polarization axes are equally excited. This property is commonly used to convert linear polarization to elliptical polarization. The characteristics of this polarization element are strongly dependent on temperature, pressure, and applied stresses. The addition of a polarizer converts such a variable waveplate into a variable in-line attenuator. Variable waveplates separated by polarizers can also form a tunable Lyot filter.
Multi-wavelength switchable random fibre laser based on double Sagnac-loop filter
Published in Journal of Modern Optics, 2021
Honggang Pan, Taotao Guo, Ailing Zhang, Chang Liu
Inspired by conventional multi-wavelength fibre lasers, multi-wavelength random fibre lasers (MWRFL) based on comb filters are proposed. Some researchers have used fibre grating arrays [14,15], all-fibre Lyot filters [16,17], and Sagnac-loop filters [18–21] and MZI [22,23] to produce stable multi-wavelength random fibre lasers. In 2005, S. Sugavanam [17] realized a random distributed feedback multi-wavelength fibre laser by using an all-fibre Lyot filter. The number of lines generated can be as high as 50, but the wavelength interval cannot be changed. In 2019, T. Feng [15] demonstrated experimentally six-wavelength channels random fibre laser using a 2 km-long single-mode fibre together with six-superimposed fibre-Bragg-gratings. However, the number of wavelengths and intervals cannot be changed. In 2020 and 2021, J. W. Liu realized multi-wavelength switchable random fibre lasers based on RDFB using a two-stage Sagnac-loop mirror [21], dual-pass MZI [22] and compound filter (a dual-pass MZI and a Sagnac-loop) [23], respectively. Similarly, the wavelength interval of these MWRFL outputs is constant.