Tunable laser based on FFP-TF2 filter

Tunable lasers are widely used in optical fiber sensing and optical fiber communications, which have attracted extensive attention. A tunable laser system based on FFP-TF2 filter was designed and built. The driving voltage generated by the DDS(direct digital frequency synthesis) function signal generator and the analog amplifying circuit designed by the FPGA was adjusted to change the cavity length of the FFP-TF2, thereby changing the output of the laser wavelength. This system could drive the single point voltage and scanning voltage of FFP-TF2, so that the single-wavelength laser and the multi-wavelength scanning laser could be output by laser. In the laser output wavelength range of 1 532 nm to 1 568 nm, the single-wavelength output and the multi-wavelength scanning range could be adjusted, and the two modes could be switched. Experimental results show that the 3 dB linewidth of the laser output is kept at about 0.01 nm, the linear fitting degree of the laser output center wavelength and the driving voltage is 99.934%, the sensitivity is 3.915 nm/V, while the linear fitting degree of the FFP-TF2 output center wavelength and the driving voltage is 99.986%, the sensitivity is 4.021 nm/V. And the error of the laser output center wavelength relative to FFP-TF2 is 2.6%, which indicates that the laser system output wavelength has the advantages of narrow line width, good stability and high flexibility.