Single-polarization, switchable dual-wavelength erbium-doped fiber laser with two polarization-maintaining fiber Bragg gratings

Abstract

An improved erbium-doped fiber laser configuration for achieving single-polarization, switchable dual-wavelength of orthogonal polarizations oscillations at room temperature is proposed. For the first time, two fiber Bragg gratings (FBGs) directly written in a polarization-maintaining (PM) and photosensitive erbium-doped fiber (PMPEDF) as the wavelength-selective component are used in a linear laser cavity. Due to the polarization hole burning (PHB) enhanced by the polarization-maintaining FBG (PMFBG), the laser can be designed to operate in stable dual-wavelength or wavelength-switching modes with a wavelength spacing of 0.336 nm at room temperature by adjusting a polarization controller (PC). Each lasing line shows a single polarization with a polarization extinction ratio of >25 dB under different pump levels. The optical signal-to-noise ratio (OSNR) is greater than 50 dB. The amplitude variation with 16 times scans in nearly one and half an hour is less than 0.5 dB at both operating wavelength.

Single linearly polarized, widely and freely tunable two wavelengths -doped fiber laser

“…Keep the environment temperature in constant and let the laser in a vibration-free environment will be an efficient way to make the oscillating more stable. (2) Using higher resolution diffraction grating or narrow linewidth PM Fiber Bragg Gratings (FBG) as the cavity reflection end in the laser will be very efficient approaches [9,10,14].…”

“…Feng et al [9] also used two polarizations maintaining (PM) FBGs in a linear cavity erbium-doped fiber laser and generated single polarization switchable dual-wavelength laser. However, all these fibers lasers contain FBGs in the laser configurations and the performance of the lasers are thus limited due to several drawbacks: First, the two wavelength separation is very narrow (less than 1 nm to few nm), Second, the separation and the central position of the two wavelength cannot be tuned freely and widely due to the very limited tunability of the FBGs [10,11].…”

Switchable Single-Polarization Dual-Wavelength Ring Laser Based on Structured PM-CFBG

“…To ensure a stable operation of an SLM dual-wavelength erbium-doped fiber (EDF) laser, we need to overcome the strong homogeneous line broadening and cross-gain saturation which lead to unstable dual-wavelength oscillation. Various techniques have been proposed to realize dual-wavelength oscillation by cooling the EDF in liquid nitrogen (77K) [3], utilizing a hybrid gain medium [4], and using polarization hole burning (PHB) effect [5]. The liquid nitrogen method is not suitable for practical applications.…”

Switchable dual-wavelength erbium-doped fiber laser based on the photonic crystal fiber loop mirror and chirped fiber Bragg grating

“…However, it is difficult to obtain the stable multi-wavelength output at room temperature in erbium-doped fiber lasers (EDFLs) because of the mode competition induced by the homogenous broadening and cross-gain saturation of the erbium-doped fiber. In order to achieve the stable multi-wavelength EDFLs at room temperature, various schemes have been proposed such as using the nonlinear polarization rotation of a highly nonlinear photonic crystal fiber [1] , adding a phase modulator [2] , introducing the saturated spectral hole burning (SHB) effect by the sampled FBG [3] and the polarization hole burning (PHB) effect by the FBGs in the fewmode fiber [4] , the FBG in the polarization maintaining fiber [5] , cascaded FBGs [6] , the sampled FBG [3] and the high-birefringence fiber loop mirror [7] .Owing to its flexible properties [8] , the photonic crystal fiber has been widely studied and offers a possibility to develop novel sensors, interferometers and other new applications. Recently, PCF interferometers based on a pair of longperiod fiber gratings or the tapering region have been proposed [9,10] .…”