棱镜非线性波导耦合光学双稳理论

THEORY OF OPTICAL BISTABILITY OF PRISM NONLINEAR WAVEGUIDE COUPLING

利用菲涅耳公式计算了棱镜非线性光波导耦合.从理论上分析了该双稳器件的调制和反馈特性,模拟出不同偏置角的光学双稳曲线,能定量地分析双稳最小偏置角,双稳阈值功率等.

The bistable bahavior originating from optical nonlinear coupling between a prism and a nonlinear waveguide by using Fresnel formulas is described. Modulation and feedback curves of the optical bistable device are analyzed. Optical bistable curves at different offset angles are calculated.The results show that the smallest offset angle and threshold of the device can be determined by using this method.In prism nonlinear waveguide coupling system, as shown in Fig. 2, assuming prism the index of refraction n0 = 1,751, gap(air) s = 100nm and its index of refraction nt = 1.000, waveguide thickness w=1400nm and its index of refraction n2 = n20 +n2EIs = 1.527 + 10-14m2/W, substrate index of refraction offset angles (values of the angle shift from the incidence coupling angle) are calculated. If the offset angle △θ<0.18', optical switch occurs. If the offset angle △θ>0.18', optical bistable operation occurs. And the hysteresis cycle width and threshlod power increase with the increase of offset angle.