ファイバ型位相変調素子を用いたスペクトル線幅測定法におけるプッシュプル駆動方式

Abstract

Push-pull drive method in linewidth measurement systems with fiber type phase modulators is developed. Firstly, we discuss the operation of a fiber type phase modulator. Then the principle of a frequency shifter, which consists of a fiber type phase modulator and a fiber coupler, is described. Secondly, we describe the operation of the push-pull drive method, which arranges an ultrasonic transducer at each end of a fiber loop. Finally, the performance of the push-pull drive method is evaluated by measuring linewidths of several laser diodes. With the push-pull drive method, the carrier component and the second side band components are suppressed by about 10dB.