Multiwavelength Fiber Laser Based Lyot-Sagnac and Nonlinear Amplifying Loop Mirror in the Presence of Faraday Mirror

Abstract

We demonstrate a multiwavelength fiber laser based Lyot-Sagnac and nonlinear amplifying loop mirror in the presence of Faraday mirror. Several polarization-maintaining fiber lengths at a selected injection current of semiconductor optical amplifiers are utilized in all measurements. The basic structure of this laser system comprises of dual-nonlinear loop mirror. The PMF is positioned in the Lyot-Sagnac loop mirror that serves as a comb filter. The effect of PMF lengths on the lasing performance concludes lengthier PMF causes narrower wavelength spacing. It is recorded for PMFs at 15 m, 18 m, and 25 m to have wavelength spacings of 0.4 nm, 0.35 nm, and 0.24 nm, respectively. The increment in SOA currents triggered a strong intensity-dependent loss mechanism that influences the intensity of light propagating through the multiwavelength fiber laser system. The gain increases as the SOA currents are increased and thus resulting in a greater number of lasing lines. The maximum lasing lines of 598 are generated with 25 m of PMF length and an injection current of 250 mA. The strong lasing lines without noticeable peak power and OSNR fluctuation have also been monitored at room temperature. Within a 60-minute time frame, the lowest OSNR stability of less than 0.51 dB is recorded using 25 m of PMF.

Keywords: Multiwavelength fiber laser, Lyot-Sagnac loop mirror, nonlinear amplifying loop mirror, Faraday mirror, lasing lines