MANUFACTURING METHOD FOR COHERENT LIGHT RECEPTION MODULE

• Main Authors: FUJIMURA YASUSHI, MORIYAMA YUTAKA, KANAMARU SEI, SUZUKI MICHIO
• Format: Patent
• Language: English; Japanese
• Published: 09.02.2017
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; TRANSMISSION

PROBLEM TO BE SOLVED: To provide a manufacturing method for a coherent light reception module, capable of making the attenuation degree of two polarization components, included in signal light, approach mutually equal magnitude.SOLUTION: The manufacturing method includes: a first step which prepares test light having two polarization components to simulate two polarization components of the signal light, to substantially equalize the strength of the two polarization components of the test light; a second step which disposes a VOA 23 on the optical path of the test light, to vary the attenuation degree of the VOA 23, while monitoring the strength of the two polarization components of the test light after attenuation, and to move the VOA 23; and a third step which fixes the VOA 23 at a position where the difference of the attenuation degree between the two polarization components of the test light after the attenuation falls within a tolerable range.SELECTED DRAWING: Figure 16 【課題】信号光に含まれる２つの偏光成分の減衰度を互いに等しい大きさに近づけることができるコヒーレント光受信モジュールの製造方法を提供する。【解決手段】この製造方法は、信号光の２つの偏光成分を模擬する２つの偏光成分を有する試験光を準備し、該試験光の２つの偏光成分の強度を互いに略等しくする第１工程と、試験光の光路上にＶＯＡ２３を配置し、減衰後の試験光の２つの偏光成分の強度をモニタしながら、ＶＯＡ２３の減衰度を変化させるとともにＶＯＡ２３を移動させる第２工程と、減衰後の試験光の２つの偏光成分の減衰度の差が許容範囲内に収まる位置にてＶＯＡ２３を固定する第３工程とを含む。【選択図】図１６