Multiwavelength $Q$ -switched Laser by Incorporating a LiNbO $_{3}$ Phase Modulator in Fabry–P

In this letter, we present a simple and compact laser cavity that can be used for Q-switching and multiwavelength oscillation. It is shown that a LiNbO₃ phase modulator with relatively low driven voltage inserted into a Fabry-Perot cavity can act simultaneously as an effective component for suppressing the homogeneous line broadening, switching the Q-value of the laser cavity, and a polarizer. Multiwavelength operation of Yb-doped fiber laser is achieved by phase modulation. Q-switching is achieved due to the residual intensity modulation of the phase modulator, and the pulse performance is also impacted by the phase modulation amplitude. Three stable wavelengths with identical wavelength spacing of 3.3 nm and pulsed laser of 0.2 muJ per pulse energy at the repetition rate of 55.8 kHz are demonstrated. The full-width at half-maximum pulse duration is of 2 mus, and the polarization extinction ratio is >23 dB.