空孔径制御を用いた偏波保持フォトニック結晶ファイバ光減衰器の作製

摘要

Photonic crystal fiber (PCF) optical attenuators that are fabricated by air hole diameter control have advantages such as low wavelength dependence of attenuation and high power resistance. In this paper, we report fabrications of polarization-maintaining PCF (PM-PCF) attenuators with air hole diameter control. The structures of PM-PCF suitable for the optical attenuator fabrication were theoretically clarified. The dependences of attenuation on air hole diameter ratio to pitch and polarization were also clarified. PM-PCF optical attenuators were fabricated by air hole diameter control using CO_2 laser irradiation. It was demonstrated that the air hole diameter ratio to pitch could be controlled by the laser power adjustment, and that the desired attenuation could be successfully obtained by the air hole ratio control.%空孔径制御により作製されたフォトニック結晶ファイバ光減衰器は，減衰量の波長依存性が小さく，耐パワー性に優れている.本稿では，空孔径制御を用いた偏波保持フォトニック結晶ファイバ(PM-PCF)光減衰器の作製について報告する.光減衰器作製に適したPM-PCFの構造を理論的に明らかにするとともに.減衰量の空孔率ならびに偏波依存性を明らかにした.CO_2レーザ照射を用いてPM-PCF光減衰器の作製を行い，照射レーザパワーの調整によりPM-PCFの空孔率を制御できることを示すとともに，空孔率制御により所望の減衰量が得られることを実証した.