MGTI型不等带宽interleaver的输出光谱特性分析

Output Spectrum Characteristics of MGTI-type Asymmetrical Optical Interleavers

用两面镜级联的GT腔代替Michelson干涉仪的两面全反射镜,通过MGTI中的GT腔镜面反射率、腔长、干涉仪臂长差等结构参量的选择,得出了宽口和窄口输出谱3dB处带宽比分别为1.69、1.83、2.13和2.14的四组不等带宽、隔离度高、通带平坦且周期不等的输出光谱,并系统分析了这些结构参量对输出光谱特性的影响.模拟结果表明:可用此类MGTI结构设计出不同带宽比的不等带宽interleaver;输出光谱的平坦特性由GT腔镜面反射率决定,镜面反射率主要影响输出谱的通带带宽与隔离度,且对两者的影响程度不同;选择适当的GT腔腔长和臂长差可得到不同的光谱周期.

Based on Michelson-Gires-Tournois interferometer （MGTI） structure of interleaver that both of reflecting mirrors were replaced by two mirror Gires-Tournois etalons （GTEs）. The appropriate value of structural parameters such as GTE front surface mirror reflectance, the cavity length of GTE and interferometer arm length difference were chosen. Four groups of spectrums that the ratio of wide bandwidth port to narrow bandwidth port at 3 dB passband （bandwidth ratio） was 1.69,1.83,2. 13 and 2.14respectively, were obtained. They have high channel isolation, wide flat top passband and different periods. The effects of these structural parameters upon output spectrum characteristics were systematically investigated. The numerical simulation results indicate that asymmetrical interleavers of different bandwidth ratios could be obtained using this MGTI. GTE front surface mirror reflectance influences the passband bandwidth and channel isolation. And the two kinds of influences are different. Choosing appropriate GTE cavity length and interferometer arm length difference, different frequency periods can be obtained.