一种通过梯形PPMgLN波导倍频实现带宽可调谐光源的理论研究

A Theoretical Study of Bandwidth Tunable Light Source by Frequency Doubling of Trapezoidal PPMgLN Waveguide

本文设计了一种梯形的周期极化掺镁铌酸锂(PPMgLN)波导,并通过在传播方向上引入温度梯度来拓宽其倍频(SHG)过程的泵浦光源可接收带宽。通过有限差分的光束传输法,计算波导的有效折射率,并进行波导尺寸的设计。结果表明,通过改变梯形波导不同位置的温度,使其形成一个温度梯度,可拓宽泵浦光源的波长可接收带宽。本文所设计的PPMgLN波导最大泵浦光源可接收带宽为C波段,即1 530~1 565 nm,该波导可倍频C波段,得到输出波段带宽为765~782.5 nm,温度调谐范围为30~150℃。

In this paper, a trapezoidal periodically poled magnesium doped lithium niobate(PPMgLN) waveguide was designed, and its acceptable bandwidth of the pump source during frequency doubling(SHG) process can be widened by introducing a temperature gradient along the propagation direction. The effective refractive index of the waveguide was calculated and the dimension of the waveguide was designed by the finite difference beam propagation method. The results show that, by changing the temperature at different positions of the trapezoidal waveguide to form a temperature gradient, the wavelength receiving bandwidth of the pump light source can be widened. The maximum receiving bandwidth of the PPMgLN waveguide pump light source designed in this paper is C-band, which range is from 1 530 nm to 1 565 nm. The waveguide can double the frequency of C-band, and the output band bandwidth is 765 nm to 782.5 nm, and the temperature tuning range is from 30 ℃ to 150 ℃.