Dual-wavelength single-frequency Erbium-doped ring fiber laser for high-resolution temperature and strain sensing

摘要

We achieve a dual-wavelength single-frequency Erbium-doped ring fiber laser by using umpumped Erbium-doped fiber and polarization-maintained fiber Bragg grating. The maximum output power is 2.11 mW when the pump power is about 225 mW, corresponding to a slope efficiency of 1%. And the SNR is larger than 60 dB. The two lasing wavelengths of the dual-wavelength ring fiber laser are 1550.16 nm and 1550.54 nm, corresponding to the linewidths of 769 Hz and 673 Hz, respectively. Meanwhile, these two lasing wavelengths can be tuned from 1550.12 nm to 1550.52 nm and from 1550.49 nm to 1550.82 nm, respectively, when the temperature is verified from 15 °C to 55 °C. It can be used as a temperature sensor with a sensitivity about 0.01 nm/°C, which possesses a resolution about ～4×10~(-6) °C through using optical heterodyne method. In addition, it can be used to realize high-resolution strain sensor by employing heterodyne method to measure the wavelength separation at the same time.