Singlemode diode-pumped tunable erbium-doped fibre laser with linewidth less than 5.5 kHz

Abstract

A diode-pumped, broadly tunable, single frequency erbium-doped fibre ring laser is reported. Tuning and single longitudinal mode selection are accomplished by use of two fibre Fabry-Perot etalons. The threshold for 1.48 μm pumping is 8.8 mW and the slope efficiency is 11.5%. The laser can be tuned to wavelengths between 1.530 and 1.575 μm and operates singlemode throughout this range. Its linewidth is measured at 1.56 μm to be less than 5.5 kHz.