Black Phosphorus Coated D-Shape Fiber as a Mode-Locker for Picosecond Soliton Pulse Generation

Abstract

We demonstrate the production of a picosecond pulse from an Erbium laser cavity using black phosphorous (BP) on side-polished fiber saturable absorber (SA) as a mode-locker. The surface of the fiber was removed utilizing a polishing wheel, and then BP was mechanically deposited onto it to develop an excellent evanescent field on the polished surface area. The SA device was used in a 56 m long Erbium-doped fiber laser (EDFL) ring cavity to generate soliton mode-locked pulses with a center wavelength of 1556.2 nm and a 3 dB spectral bandwidth of 2.2 nm. Stable 3.48 MHz soliton pulses with pulse width as short as 1.17 ps were achievable by setting the pump power within 92 mW to 145 mW. The highest pulse energy and peak power obtainable were 5.4 nJ and 4.7 kW, respectively. The results show that BP deposited onto side-polished fiber can be used as an SA in an EDFL cavity. Its easy construction makes it suitable for producing a portable mode-locked laser source.