  Low-dimensional materials, due to their versatile properties are very
interesting for numerous electronics and optoelectronics applications. Recently
rediscovered black phosphorus, with a graphite-like structure can be exfoliated
up to the single atomic layer. In contrary to graphene it possesses a direct
band gap controllable by the number of stacked atomic layers. For those
reasons, it is now intensively investigated. Here we demonstrate, that black
phosphorus can serve as a broadband saturable absorber and can be used for
ultrashort optical pulse generation. The mechanically exfoliated ~300 nm thick
layers of black phosphorus were transferred onto the fiber core and under
pulsed excitation at 1560 nm wavelength its transmission increases by 4.4%. It
was used to generate 272 fs-short pulses at 1550 nm and 739 fs at 1910 nm. The
obtained results shows that black phosphorus can be effectively used for
ultrashort pulse generation and proves its great potential to future
applications.
