提出并演示了一种结合外调制和受激布里渊散射(SBS)放大技术、通过信号包络恰当延时而叠加产生三角波信号的新方法。该方案中激光器发出的连续光分为两路,一路经过马赫-曾德尔调制器(MZM)产生频率为斯托克斯(Stokes)频移量三分之一的基频调制信号,另一路作为SBS抽运光放大调制信号的正三阶边带获得三倍频谐波信号。两路信号的包络经过独立相位控制和功率调节,恰当延时后叠加可产生良好近似的三角波信号。通过改变连续光波长,产生的三角波信号频率可实现一定范围内的调谐。理论仿真和实验结果均证明了此方案的可行性,其避免了复杂的谱线操作,提高了系统稳定性,为任意波形产生技术提供了新思路。
Combined with external modulation and stimulated Brillouin scattering(SBS) amplification technology,a new method of generating triangular waveform signal by synthetizing signal envelopes with proper time delay is proposed and demonstrated. In this scheme, the continuous light emitted by lasers is divided into two branches.One is modulated by Mach-Zehnder modulator and the fundamental frequency modulation signal, one third of the Stokes frequency shift is obtained. The other is used as SBS pump light to amplify the positive 3rd-order sideband of the modulation signal, and a frequency tripling harmonic signal is obtained. After independently controlling the phase and power of envelopes of the two harmonic signals, a triangular waveform signal with good approximation is generated by synthetizing these two signal envelopes with proper time delay. By changing the wavelength of continuous wave, the frequency of the generated triangular waveform signal can be tuned in a certain range. The feasibility of this scheme is proved in theoretical simulation and experiment. The scheme avoids complex spectral lines manipulation and the system stability is improved. It provides a new idea for arbitrary waveform generation technology.