光周波数および繰り返し周波数を同時安定化した40GHz再生モード同期パルスレーザ

摘要

繰り返し周波数が10～40GHzであるピコ秒短パルス光源の開発は，超高速光通信，マイクロ波フォトニクス，ならびに光度量衡などの分野において大変重要である．特に，コヒーレント光通信や光度量衡にパルスレーザを応用する場合，その光周波数安定化が強く望まれる.前回，我々は再生モード同期パルスレーザを用いた繰り返し周波数と光周波数の独立制御技術を新たに提案した．本稿では，この制御技術と従来の分子吸収線を用いた光周波数安定化技術を組み合せ，光周波数および繰り返し周波数を同時に安定化した40GHzピコ秒パルスレーザを実現したので報告する．%Ultrastable mode-locked pulse lasers operating in the GHz region have been receiving a lot of attention with respect to their application to both ultrahigh-speed optical transmission, micro-photonics and optical metrology. In particular, control of the laser frequency is very important for optical coherent communication and optical metrology applications. In this paper, we have succeeded in the simultaneous stabilization of the optical frequency and repetition rate of a 40 GHz regeneratively mode-locked picosecond erbium-doped fiber ring laser. The optical frequency was locked to the molecular absorption of C_2H_2 in the 1.5.μm band and the repetition rate was stabilized to a 40 GHz synthesizer by using a microwave phase-locked loop.