Impact of filter parameters on pulse performance in Er-doped fiber Mamyshev oscillator

Based on the offset filtering effect, the Mamyshev oscillator (MO) has recently emerged as one of the most effective methods for generating ultra-short, high-energy pulses in fiber lasers. The filter parameters are crucial factors in determining the laser performance of MO. Most previous studies examined the effects of filter parameters through simulations; experimentally, only the influence of filter separation has been explored, while simultaneous investigation of filter bandwidth and separation remains limited to numerical studies. In this work, by employing a waveshaper as one of the flexible filters, we were able to programmatically adjust the filter parameters. This approach enabled a comprehensive experimental investigation into the influence of filter parameters on the MO pulse. Our findings indicate that wider filter bandwidth and larger filter separation are advantageous for achieving higher pulse energy and a broader spectrum. After evaluating various factors, pulse with highest pulse energy of 14.1 nJ and a 10-dB spectral bandwidth of 104.29 nm can be achieved in our MO. Simulation results agree well with experimental data. Moreover, both experimental and numerical results confirmed that the actual gain spectrum of the Er-doped fiber has influence on the laser performance. These results contribute to a deeper understanding of the MO and its potential for enhanced pulse generation.