Germanene nanosheets for mode-locked pulse generation in fiber lasers

Based on an as-prepared high-quality germanene-polyvinyl alcohol (germanenen-PVA) film, the mode-locked operation and 2th, 4th, 5th and 6th order harmonic mode-locked operations with high stability were gener-ated in an erbium-doped (Er-doped) fiber laser for the first time. The mode-locked pulse with a fundamental of 3.9 MHz and a pulse energy of 2.47 nJ was obtained, corresponding to the signal-to-noise ratio (SNR) of about 90 dB. In addition, the characteristics of four kinds of harmonics with frequencies of 7.8 MHz, 15.7 MHz, 19.6 MHz and 23.5 MHz were also systemically investigated. The results proved that the germanene can be used as an excellent nonlinear photonic device for pulse lasers.

Automated summary

The mode-locked and harmonic mode-locked operations were achieved in an erbium-doped fiber laser using a high-quality germanene-polyvinyl alcohol film. The germanene film showed promising potential as a nonlinear photonic device for pulse lasers.