Tunable fiber laser with nano-thick silver diaphragm as compound external cavity

An optimized tunable fiber laser has been proposed by using a novelty developed silver diaphragm at the end of coupled cavity of the tunable fiber laser. The total tuning range is about 15 nm by using a combination of axial compressive strain and a tensile strain. The lasing mode regime of tunable fiber laser is determined by the fiber laser compound cavity. Experimental results demonstrate that the characteristics of tunable fiber laser with external cavity not only present good stability performances with the output power variation about 0.2 dB and the wavelength fluctuation less than 0.08 nm, but also could reduce threshold pump power, decrease the linewidth from 19.557 kHz to 7.271 kHz by coupling silver membrane at the end of the fiber truncation. The optimized tunable fiber laser of external cavity configuration is in good agreement with the theoretical analysis and has many potential applications in sensing and communication system for high sensitivity and remote measurement.