The intensity balance ratio (IBR) tuning mechanism of Nd:GdVO<sub>4</sub> monolithic microchip dual-frequency laser (DFL) is presented. The intensity balanced DFL signals are obtained by precisely controlling the heat sink temperature of the Nd:GdVO<sub>4</sub> crystal. In experiments, the DFL signal with frequency separation at 64 GHz and IBR above 0.99 is realized with the temperature at 47.6 °C. The other balanced intensity distribution can be reached at -0.9 °C before mode hopping. Moreover, utilizing the fluorescence spectrum and the intensity balance points of Nd:GdVO<sub>4</sub> DFL, we obtain the temperature difference between internal and external of Nd:GdVO4 crystal Δ<i>T</i> = 24.0 °C.
A widely tunable single-wavelength Brillouin fiber laser (BFL) incorporating a bismuth-based erbium-doped fiber (Bi-EDF)
is proposed. The 52 cm-long highly erbium-doped Bi-EDF provides broadband gain extending from the C-band (1525-1565
nm) to the L-band (1565-1625 nm). In experiment, the BFL operates in a range from 1555 nm to 1632 nm, which is the
widest to the best of our knowledge. The proposed BFL is an attractive narrow linewidth laser source on the L-band, which
has many potential applications, such as in slow light, coherent communication, and interferometric sensing.