Attosecond-Resolution Er:Fiber-Based Optical Frequency Comb**Supported by the National Natural Science Foundation of China under Grant Nos 91336101 and 61127901, and the West Light Foundation of the Chinese Academy of Sciences under Grant No 2013ZD02.

Abstract

Highly stable frequency-controlled optical frequency combs are key elements of many applications in time-frequency and optical-metrology domains. In this work, we demonstrate a highly stable frequency-controlled erbium-fiber-based optical frequency comb system. Its repetition rate is phase-stabilized to a continuous-wave laser with both an intra-cavity electro-optic modulator and a piezo-transducer; while the carrier-envelope-offset frequency is phase-locked to a radio-frequency signal generator by controlling the pump power. In-loop relative frequency stabilities of the comb are below 1 × 10−16 at 1 s, and integrate down to low 10−20 level at 104 s. The corresponding timing uncertainties are 100–200 as over the full measurement range.