▎ 摘　　要

We propose and experimentally demonstrate a bidirectional erbium-doped fiber laser delivering dispersion -managed soliton (DMS) and Q-switched pulse based on a graphene-polyvinyl alcohol (PVA) and nonlinear optical loop mirror (NOLM) saturable absorbers (SAs). In proposed structure, the DMS is achieved in clockwise (CW) direction and Q-switched pulse is obtained in counter-clockwise (CCW) direction. By properly adjusting the intracavity attenuators (ATT) and polarizer controllers (PCs), DMS in the CW direction and Q-switched pulse in the CCW direction can be obtained, respectively or simultaneously. The DMS with full width at half maximum (FWHM) of similar to 480 fs, signal to noise ratio (SNR) of 60 dB and repetition frequency about 3.907 MHz is obtained. The Q-switched pulse is established at a pump power of 180 mW with a repetition rate of similar to 43.5 kHz and FWHM of similar to 8.18 mu s. When the pump power is increased to 700 mW, Q-switched pulse with a repetition rate of similar to 107.1 kHz and FWHM of similar to 2.15 mu s is generated. When the two type pulses are formed simultaneously, the maximum repetition rate of Q-switched pulse is 55.8 kHz and minimum FWHM is 2.81 mu s, the DMS can be formed by properly adjusting PC and ATT in this case. To the best of our knowledge, it is the first time that Q-switched pulse and DMS have been acquired respectively or simultaneously in a fiber laser. (C) 2016 Elsevier Ltd. All rights reserved.