本研究利用紫外光照射光子晶體波導，造成光子晶體區域之折射率對比改變，進而產生光能隙位移（bandgap shift），使得操作於能隙邊緣波長的訊號光穿透率大幅下降或者上升，成為一全光開關機制。 實驗上以五氧化二鉭（Ta2O5）作為波導層，並且在波導上製作光子晶體結構；量測上，利用鎖模鈦藍寶石雷射作為入射光源（probe beam）、連續波紫外光作為幫浦光（pump beam），開關對比度達92.98%，未來的研究將著重於開關速度之提升。In this study, we use ultraviolet light as the pump beam to illuminate the waveguide which contains photonic crystal in it. The refractive index change results in the shift of the bandgap of the photonic crystal. The transmission of the signal beam operated at bandedge wavelengths is thereby modulated and all-optical switching is realized. Experimentally, Ta2O5 is used as a material for the waveguide. E-beam lithogography technique is utilized to fabricate the photonic crystal structure in the waveguide. The performed on/off characteristic shows that a transmission contrast as high as 92.98% can be achieved. Future direction of work is discussed aiming at the improvement of the switching speed.
