Octave-Spanning Comb Generation and Optical Frequency Measurement Using Mode-Locked Fiber Lasers

Abstract

Recent developments in fiber based frequency combs have made them the preferred link between optical and microwave frequencies. This is due to their robustness and cost-effectiveness. We have developed fiber based frequency combs at NMIJ (National Metrology Institute of Japan) and used them to measure a range of wavelengths, including stabilized lasers with wavelengths at 633, 1064, 1542nm. Our comb has continuously worked for over 1 and half years in our laboratory. In addition, one of our fiber combs was recently shipped to the Australian National Measurement Institute to perform a comb comparison with the NMIA (National Measurement Institute, Australia) fiber comb. In this paper, we firstly survey the octave-spanning comb generation and optical frequency measurement using mode-locked lasers. We subsequently describe a development of the fiber comb at NMIJ, and the results of the comb comparison performed in Australia. The consistency of the frequency measurements of the comb comparison reached to the 10^-16 level.