L波段可切换双波长高能量脉冲光纤激光器

报道了一种基于主振荡功率放大（Master Oscillator Power Amplifier, MOPA）结构的L波段可切换双波长且频率稳定的高能量单频偏振脉冲光纤激光器，可作为探测大气CO₂激光雷达系统的发射光源。该脉冲光纤激光器系统主要由两个单频窄线宽外腔半导体激光器、脉冲调制系统和多级光纤放大器组成。通过控制磁光开关，可以实现1572.018 nm和1572.480 nm双波长自由切换。采用闭环温度控制技术，实现了种子激光器的输出频率和功率锁定。采用数字和模拟声光调制器串联，实现了高达80 dB的通断消光比。通过对光纤施加非均匀应力，从而提高了受激布里渊散射（Stimulated Brillouin Scattering, SBS）阈值。利用普通商用增益光纤及商业化保偏元器件，在波长1572 nm、重复频率10 kHz时，实现平均输出功率1.5 W，脉宽309 ns，峰值功率485 W，单脉冲能量大于150 μJ，信噪比大于25 dB的激光输出。整个激光器系统采用风冷散热且电功耗小于60 W。

L-band switchable dual-wavelength,high-energy pulsed fiber laser

An L-band switchable dual-wavelength, frequency stabilized, high energy, single frequency, single mode linearly polarized, pulsed laser based on a master osocillator power amplifier (MOPA) configuration was reported. It could be used as the emission source of detecting atmospheric CO₂ LIDAR system. This pulsed fiber laser system was mainly composed of two single frequency narrow linewidth external cavity semiconductor lasers, pulse modulation system, and multi-stage fiber amplifiers. The wavelengths of 1572.018 nm and 1572.480 nm could be switched freely by controlling a magneto-optical switch. Using the closed loop temperature control technology, the locked central frequency and output optical power were implemented. The on-off extinction ratio of 80 dB was achieved by using digital and analog acousto-optic modulators in series. The Stimulated Brillouin Scattering (SBS) threshold was increased by applying non-uniform stress to the fiber. With a common commercial gain fiber and commercial polarization maintaining components, an average output power of 1.5 W, pulse width of 309 ns, the peak power of 485 W, pulse energy of 150 μJ and signal to noise ratio of 25 dB were generated at a repetition rate of 10 kHz and the wavelength of 1572 nm. The power consumption of the whole laser system which used air cooling was less than 60 W.