Absolute Frequency Comb Mode Number Determination

The frequency comb technique is a very useful method to measure the frequency of lasers accurately. The authors proposed a new method that is simpler and can be used for both high and low repetition rate frequency combs without the help of a wavemeter. The method is a two-step process. The authors first obtain a rough estimate of N by changing the repetition rate fr. a small amount such that no mode number change occurs..