報告書番号

R95004

タイトル（和文）

偏光状態の高速制御方式の検討

タイトル（英文）

概要 （図表や脚注は「報告書全文」に掲載しております）

光学的偏波制御方式の高速化への課題を抽出し，ＯＰＧＷの高速な偏波変動に対応する制御装置を設計した。（１）バルク結晶で低電圧化を図るためＺ伝搬ニオブ酸リチウム結晶を適用した。（２）偏波移動を最短化するため素子の４面に電極を構成し電界方向と電界強度を用いて複屈折主軸方向と移相角を同時制御とした。（３）制御系を高速化するため、入力光の偏波監視情報から必要なＸＹ方向の制御電圧を直接導出する式を導出した。

概要 （英文）

CONTROL OF STATES OF POLARIZATION(SOP) FLUCTUATION CAN PROVIDE NEW APPLICATIONS FOR OPTICAL-FIBER COMMUNICATION INCLUDING COHERENT TRANSMISSION. HOWEVER,SOP FLUCTUATION AS THE ORDER OF 10MU OCCURS IN THE OPGW DUE TO LIGHTING BY LIGHTNING. THIS PAPER DESCRIBES FAST OPTICAL POLARIZATION CONTROL TECHNIQUES. THE MAIN RESULTS ARE AS FOLLOWS: (1)AN ELECTRO-OPTIC DEVICE OPERATED BY LATERAL VOLTAGE CAN BE USED BECAUSE THE LONG PATH PROVIDES HIGH SENSITIVITY. A Z-PROPAGATIONLN (LINBO3) CRYSTAL CAN BE OPERATED BY LATERAL VOLTAGES. FOR A BULK DEVICE 1-MM THICK AND 40-MM LONG FOR SINGLE-MODE FIBER,THE REQUIRED VOLTAGE IS 500 V AT LAMBDA=1.55MU M, WHICH IS FEASIBLE. (2)CONTROL OF BOTH THE PRINCIPAL AXIS ANGLE PHI AND PHASE SHT ANGLE DELTA OF THE BIREFRINGENCE MOVE THE SHO RTEST LOCUS. A CONFIGURATION WITH FOUR ELECTRODES ON EACH FACE TO APPLY ORTHOGONAL VOLTAGES VX AND VY PROVIDES SIMULTANEOUS CONTROL OF PHI AND DELTA, WHICH ARE PROPORTIONAL TO 50% OF THE ELECTRIC FIELD DIRECTION ANGLE,AND ITS STRENGTH,RESPECTIVELY. (3)A DIRECT PROCESS FROM SOP MONITORING TO CONTROL OUTPUT IS EFFECTIVE FOR FAST CONTROL. THE EQUATIONS TO DERIVE VX AND VY FROM THE INPUT SOP WERE OBTAINED FOR FAST PROCESSING AND A FAST CONTROL SYSTEM DESIGN HAS BEEN BASED ON THEM.

報告者

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