{"created":"2023-06-19T10:29:12.828468+00:00","id":8949,"links":{},"metadata":{"_buckets":{"deposit":"2dbfe60a-b7d9-4eef-adc1-554dd904d5cc"},"_deposit":{"created_by":18,"id":"8949","owners":[18],"pid":{"revision_id":0,"type":"depid","value":"8949"},"status":"published"},"_oai":{"id":"oai:muroran-it.repo.nii.ac.jp:00008949","sets":["41:227"]},"author_link":["42162"],"item_81_date_granted_17":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2016-03-23"}]},"item_81_degree_grantor_10":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_language":"ja","subitem_degreegrantor_name":"室蘭工業大学"},{"subitem_degreegrantor_language":"en","subitem_degreegrantor_name":"Muroran Institute of Technology"}],"subitem_degreegrantor_identifier":[{"subitem_degreegrantor_identifier_name":"10103","subitem_degreegrantor_identifier_scheme":"kakenhi"}]}]},"item_81_degree_name_11":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士（工学）","subitem_degreename_language":"ja"}]},"item_81_description_25":{"attribute_name":"フォーマット","attribute_value_mlt":[{"subitem_description":"application/pdf","subitem_description_type":"Other"}]},"item_81_description_7":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"インターネットやスマートフォンの普及とともに近年通信量がますます増大している。通信のさらなる大容量化を達成するためには，光の伝送路である光ファイバや光信号を処理するための光回路素子のさらなる性能向上が必須である。こうした中，フォトニック結晶ファイバ（PCF）は，従来の光ファイバでは得られない特異な性質を実現できることから，活発に研究が行われている。その特性の一つに絶対単一偏波伝送があり，中でも，楕円空孔コア円形空孔ホーリーファイバ（EC-CHF）は，コア部に楕円空孔を導入することで異方性を生みだし，x偏波とy偏波のどちらか一方の偏波に対してのみコア部の等価的屈折率をクラッド部よりも大きくすることで容易に広帯域な単一偏波伝送を実現できる。本研究では，この EC-CHFの単一偏波伝送特性を利用した新たなクロストークのない光デバイスを提案し，その設計方法，光伝搬特性，構造トレランスについて詳細な検討を行っている。　本研究では，まず，三角格子EC-CHFを用い，クロストークのない新たな方向性結合型偏波分離素子を提案している。コア部に真円空孔を配置した偏波無依存導波路（CC-CHF）を入射導波路とし，その左右にx偏波のみを伝送するxEC-CHF，y偏波のみを伝送するyEC-CHFを出力導波路として配置する。この構成では，各偏波は一方のEC-CHFにしか結合できないため，本質的に偏波クロストークのない偏波分離を実現できる。また，偏波ごとに位相整合条件を満足させることが可能であり，設計自由度が高い。この新しい偏波分離素子の設計方法および構造パラメータと動作特性について詳細な検討を行っている。次に，正方格子EC-CHFを用い，コア部の楕円空孔を傾斜させた変換長の短い偏波変換素子を提案している。正方格子の対称性を利用し，コア部楕円空孔を結晶の主軸方向から４５度傾けることで２つの直交偏波間で完全な偏波変換が可能である。さらにこの偏波変換素子の左右に入出力導波路としてxEC-CHF，yEC-CHFを配置することで，クロストークのない偏波変換素子を提案し，その動作特性について詳細に検討を行っている。最後に，偏波とモードの一括分離のための基礎検討として，正方格子EC-CHFを用いたモード分離素子の提案も行っている。ここでは，３モード（E_11^x,E_12^x,E_21^x  ）伝送xEC-CHFを入射導波路とし，その左と上に出力とする単一モードCC-CHFが置かれたL字型構成としている。高次モードである E_12^x,E_21^x  モードは基本モードに変換され出力導波路に結合する。その際，界の対称性から E_12^x,E_21^x   モードはそれぞれ左側および上側のCC-CHFとしか結合しないためモードクロストークを抑えることができる。　本研究で提案した構造は単一偏波EC-CHFを用いているため，ファイバ間の結合を偏波/モードごとに限定することができ，各結合導波路を個別に設計でき，高い設計自由度を持っている。偏波分離素子と偏波変換素子を組み合わせ，ファイバ型偏波分離・変換素子を実現できる。また，偏波分離素子とモード変換・分離素子を組み合わせて光通信システムに応用することで，偏波多重(PDM)とモード多重(MDM)システムを同時に実現できる。","subitem_description_language":"ja","subitem_description_type":"Abstract"},{"subitem_description":"With the development of information society, the demand for high-speed large-capacity optical communication system is further increased. In order to achieve this objective, demand for high-performance optical devices has also been increased. In recent years, photonic crystal fibers (PCFs), which consists of single material with a periodical array of air holes around the fiber core, have attracted a lot of attention due to their special properties that cannot be obtained by the conventional fibers. One of these properties is the absolutely single polarization transmission, and a novel single-polarized PCF with a core consisting of elliptical-holes, which is called elliptical-hole core circular-hole holey fiber (EC-CHF), has been proposed recently for achieving the single polarization transmission easily. In our research, we propose and design three kinds of novel passive optical devices based on the single-polarized EC-CHFs. Utilizing the full-vector finite-element method (FV-FEM) and the full-vector finite-element beam propagation method (FE-BPM), we investigate the optimal structural parameters, light propagation behaviors and structural tolerance of each proposed optical device in detail. In our research, firstly, we propose a cross-talk free polarization splitter (PS) based on three triangular lattice EC-CHFs. An EC-CHF with circular air holes in the core region is polarization independence, here we refer to it as a CC-CHF and use it as the input waveguide. An xEC-CHF which can transmit only x-polarized light, and a yEC-CHF which can transmit only y-polarized lightare placed on both sides of the CC-CHF and used as the output waveguides. Simulation results illustrate that the PS can completely split an arbitrarily polarized light beam into two orthogonal polarization states without any cross-talk. After that, a novel polarization converter (PC) based on square lattice EC-CHF with 45 degrees oblique elliptical holes in the core has been proposed. Utilizing the symmetry property of the square lattice EC-CHF, an incident x- or y-polarized wave can be converted 90 degrees. Moreover, we adopt two EC-CHFs on both sides of the PC to obtain a cross-talk free structure. Finally, a L-shaped mode converter/splitter (MCS), which has an xEC-CHF in the middle and two single-mode CC-CHFs at left and upper side, has been considered based on square lattice EC-CHF. Since the two higher modes (E_12^x  and E_(21 )^x) of xEC-CHF have the different symmetry along the x- and y-axis, with the light  propagation, two incident higher modes can be converted into the corresponding fundamental modes and coupled into each output CC-CHF, respectively. In our research, we design the passive optical devices using single-polarized EC-CHFs and our proposed devices have a high design flexibility. Such as a novel polarization splitter-converter can be obtained by combining the PS and PC which we have designed. Moreover, a high-performance optical device based on our proposed PS and MCS can make a contribution to the polarization division multiplexing (PDM) and mode division multiplexing (MDM) systems simultaneously.","subitem_description_language":"en","subitem_description_type":"Abstract"}]},"item_81_dissertation_number_13":{"attribute_name":"学位授与番号","attribute_value_mlt":[{"subitem_dissertationnumber":"甲第387号"}]},"item_81_identifier_registration":{"attribute_name":"ID登録","attribute_value_mlt":[{"subitem_identifier_reg_text":"10.15118/00008932","subitem_identifier_reg_type":"JaLC"}]},"item_81_subject_9":{"attribute_name":"日本十進分類法","attribute_value_mlt":[{"subitem_subject":"548","subitem_subject_scheme":"NDC"}]},"item_81_text_12":{"attribute_name":"学位の種別","attribute_value_mlt":[{"subitem_text_language":"ja","subitem_text_value":"課程博士"}]},"item_81_text_14":{"attribute_name":"報告番号","attribute_value_mlt":[{"subitem_text_language":"ja","subitem_text_value":"甲第387号"}]},"item_81_text_15":{"attribute_name":"学位記番号","attribute_value_mlt":[{"subitem_text_language":"ja","subitem_text_value":"博甲第387号"}]},"item_81_text_16":{"attribute_name":"研究科・専攻","attribute_value_mlt":[{"subitem_text_language":"ja","subitem_text_value":"工学専攻・先端情報電子工学コース"}]},"item_81_version_type_24":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_version_resource":"http://purl.org/coar/version/c_970fb48d4fbd8a85","subitem_version_type":"VoR"}]},"item_access_right":{"attribute_name":"アクセス権","attribute_value_mlt":[{"subitem_access_right":"open access","subitem_access_right_uri":"http://purl.org/coar/access_right/c_abf2"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorAffiliations":[{"affiliationNameIdentifiers":[],"affiliationNames":[{"affiliationName":""}]}],"creatorNames":[{"creatorName":"張, 沢君","creatorNameLang":"ja"},{"creatorName":"ZHANG, Zejun","creatorNameLang":"en"}],"familyNames":[{},{}],"givenNames":[{},{}],"nameIdentifiers":[{}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2016-06-08"}],"displaytype":"detail","filename":"A387_summary.pdf","filesize":[{"value":"549.8 kB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"A387_summary","objectType":"abstract","url":"https://muroran-it.repo.nii.ac.jp/record/8949/files/A387_summary.pdf"},"version_id":"dd6a651a-2478-4986-adb0-fef24e9ea1c5"},{"accessrole":"open_access","displaytype":"detail","filename":"A387.pdf","filesize":[{"value":"4.1 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"objectType":"fulltext","url":"https://muroran-it.repo.nii.ac.jp/record/8949/files/A387.pdf"},"version_id":"a6081551-a3f7-40e4-ba88-0a19afe8f130"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"doctoral thesis","resourceuri":"http://purl.org/coar/resource_type/c_db06"}]},"item_title":"Design of optical devices based on single-polarized elliptical-hole core circular-hole holey fiber","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Design of optical devices based on single-polarized elliptical-hole core circular-hole holey fiber","subitem_title_language":"en"},{"subitem_title":"楕円空孔コア円形空孔ホーリーファイバを用いた光デバイスの設計","subitem_title_language":"ja"}]},"item_type_id":"81","owner":"18","path":["227"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2016-06-08"},"publish_date":"2016-06-08","publish_status":"0","recid":"8949","relation_version_is_last":true,"title":["Design of optical devices based on single-polarized elliptical-hole core circular-hole holey fiber"],"weko_creator_id":"18","weko_shared_id":-1},"updated":"2023-10-27T06:05:52.627375+00:00"}