Two types of ultrafast mode-locking operations generation from an Er-doped fiber laser based on germanene nanosheets

Saturable absorbers as passive modulators in passively mode-locked fiber lasers play a crucial role in the generation of ultrashort pulses. Germanene, a graphene-like two-dimensional material with fast carrier relaxation time and large nonlinear absorption coefficient comparable to that of graphene, is a saturable absorber material with very fast response.

Researchers led by Prof. Wei Xia at University of Jinan (UJN), are interested in modulation switches in fiber lasers, and two-dimensional material saturable absorbers have been a hot research topic in recent years.

Two-dimensional materials make up for the disadvantages of traditional artificial saturable absorbers such as nonlinear polarization rotation and nonlinear amplification loop mirror with poor environmental stability and complex structure. And germanene, as an emerging two-dimensional material, has excellent nonlinear optical properties, and fully exploring its potential performance has a positive contribution to the development of passive modulators.

The researchers predict its potential applications. Using it as a saturable absorber, the femtosecond pulse and higher energy noise-like pulse can be obtained.

The work is published in the journal Frontiers of Optoelectronics.