摘要
针对线性啁啾光栅反射谱有震荡、两侧有旁瓣等问题,从耦合模理论出发,研究了调制深度Δn、光栅长度L和啁啾系数C等对其反射谱的影响,深入探讨了重要参数与特性的关系。提出了基于折射率补偿的非对称变迹优化方法,探寻了有效的变迹函数、补偿系数和最佳比例。结果表明,随着L(5~100mm)、Δn(10^(-5)~10^(-3))和C(0.01~0.2nm/cm)的增大,峰值都向长波长方向漂移,3dB带宽都增大,分别为1.79、1.26和1.71nm,且基本成线性关系;L较小时,反射谱顶部有较大震荡;Δn较大时,反射谱两侧出现明显旁瓣。优化后时延线性区域增大,色散曲线更平稳,反射谱顶部较平坦,没有旁瓣,带宽没有减小,具有更好的光学特性。
In order to solve the problems of oscillation on the top and side lobes of reflection spectrum for linear chirped grating, the influences of refractive index modulation depth, grating length, chirp coefficient on reflection spectrum are studied based on coupled mode theory, and the relationship between parameters and characteristics are deeply explored in this paper. A asym- metric apodized optimization method based on refractive index compensation is proposed. The effective apodization functions, compensation factor and optimal piecewise apodization ratio are also explored. Simulation results show that the peak shifts to the direction of longer wavelength, and the 3 dB bandwidths increase basically linear with L （5-100 mm）, An （10-5-10- 3） and C （0.01-0.2 nm/cm）, which can achieve 1.79, 1.26, 1.71 nm, respectively. The peak value increases with L and An, and decreases with C. There is a big shock at the top when L is small. When An is large, obvious side lobes appear on both sides of the central spectrum. After applying the optimization algorithm, the linear region has increased, and the dispersion curve has been more stable. Compared to the traditional algorithm, the top of reflection spectrum is much more flat with no side lobe and no bandwidth reduction. The proposed optimization algorithm shows the better optical characteristics.
出处
《光通信研究》
北大核心
2018年第1期38-42,共5页
Study on Optical Communications
基金
安徽省高等学校自然科学研究项目(KZ00216024)
安徽省高等学校优秀青年人才基金资助项目(2012SQRL219)
关键词
啁啾光栅
反射谱
优化
非对称
补偿系数
chirped grating
reflectance spectrum
optimization
asymmetric
compensation factor
