CAJ | 학술논문

在传统的基于全内反射原理的低折射率比介质波导所构建的相位移调制型光学器件中,调制区域的长度通常在毫米到厘米量级.由于器件横向尺寸保持在微米量级,因此狭长结构成为了传统光波导器件的典型特征,这限制了光学器件集成度的提高,严重制约了集成光路的进一步发展.光子晶体的出现为高密集成光路的发展提供了一条新的途径.本文使用平面波展开方法计算了光子晶体线缺陷波导中的色散曲线.研究发现:在色散曲线下边缘处,材料折射率的一个微小变化可以引起传输常数的较大变化,如果工作频率点选择在带下边缘附近,则可以大幅度减小相位移调制型器件调制区域的长度.本文使用时域有限差分方法进一步验证这种增强效应,计算结果表明,对于0.46％的折射率变化,光子晶体线缺陷波导中的相位调制长度仅为均匀媒质中相位移调制长度的11.7％.通过以进一步研究,这种增强效应有望应用与高密度集成光路.
재전통적기우전내반사원리적저절사솔비개질파도소구건적상위이조제형광학기건중,조제구역적장도통상재호미도전미량급.유우기건횡향척촌보지재미미량급,인차협장결구성위료전통광파도기건적전형특정,저한제료광학기건집성도적제고,엄중제약료집성광로적진일보발전.광자정체적출현위고밀집성광로적발전제공료일조신적도경.본문사용평면파전개방법계산료광자정체선결함파도중적색산곡선.연구발현:재색산곡선하변연처,재료절사솔적일개미소변화가이인기전수상수적교대변화,여과공작빈솔점선택재대하변연부근,칙가이대폭도감소상위이조제형기건조제구역적장도.본문사용시역유한차분방법진일보험증저충증강효응,계산결과표명,대우0.46％적절사솔변화,광자정체선결함파도중적상위조제장도부위균균매질중상위이조제장도적11.7％.통과이진일보연구,저충증강효응유망응용여고밀도집성광로.
In the phase shift modulation type optical components constructed by traditional dielectric waveguides with the low refractive index constant based on the total inner reflection mechanism,the length of the modulation region is usually millimeter or centimeter order of magnitude,while their horizontal size is micrometer of order of magnitude,therefore,the most typical characteristics of optical waveguide devices are long and narrow.Reducing the size of optical waveguide devices is a hard problem in the development of highly dense integrated optical circuits.The emergence of photonic crystals provides a new approach to develop highly dense integrated optical circuits.The plane wave expansion method is used to calculate the dispersion curves of the line-defect type photonic crystal waveguides.It is observed that there is a large change of wave prorogation constant near the guided-wave band edge,corresponding to a little change of refractive index of the material.If the work frequency is selected near the guided-wave band edge,the phase shift modulation length is expected to largely reduce.The finite-difference time-domain method is used to demonstrate the results above.Calculated results indicate that there is strong enhancement effect of refractive index phase shift modulation near guided-wave band edge:for the refractive index change of 0.46％,the phase shift modulation length in these waveguides is only 11.7％ of that in conventional uniform dielectric material.This enhancement effect is originated from the special flat dispersion properties near the guide-wave band edge,and it is expected to be applied to high dense photonic integrated circuits after further research.