基于周期极化晶体的Solc型滤波器透射谱的研究

Study on the transmission spectrum of Solc-type filter in PPLN

利用外加电场极化法制作周期极化晶体时占空比一般存在着较大误差,因此本文分析了基于周期极化铌酸锂晶体(PPLN)的Solc型滤波器,在非理想占空比下(D≠1/2)的滤波特性,用耦合波理论推导了D为任意值时的透过率公式。指出通过增加电压,非理想占空比下中心波长的透过率与理想占空比D=1/2时的情况相同,仍然可以达到100%(忽略损耗),同时两者的透射谱也相同。

The charactenshcs of Solc- type filter in ponodically poled lithium mobate（PPLN）with imperfect duty cycle（D≠1/2）are studied since there are great errors in the duty cycle of periodically poled crystals fabricated by extemal electric poling technique. The transmission spectrum formulae of PPLN Solc-type filter with arbitrary duty cycle are derived from coupled mode theory. The transmission of the fundamental wavelength could reach 100% （ neglecting losses）if the electric voltage applied along the transverse direction of the PPLN is increased, which is the same as that with the ideal duty factor. And so as the spectrum.