Frequency measurement of acetylene-stabilized lasers using a femtosecond optical comb without carrier-envelope offset...

We have established a frequency measurement system for frequency-stabilized lasers operating in telecommunication wavelength bands, by using a femtosecond optical comb without the need for carrier envelope offset frequency control. This system has been used to measure the frequency of an acetylene-stabilized laser operating at 1542 nm for a period of over 10 hours. The frequency stability of the acetylene-stabilized laser is estimated to be 3x10-12 for a 10-s averaging time, improving toward 1x10-13 after 10000 s. We have measured three acetylene-stabilized lasers, including one commercially available laser, and confirmed that the frequency values are in good agreement (a frequency scatter of 2.1 kHz) with previously measured results reported by different institutes. In addition to the P(16) line of acetylene at 1542 nm, we measured the absolute frequencies of the P(24) line at 1547 nm, the P(1) line at 1534 nm, and the R(5) line at 1530 nm with a view to improving the accuracy of the acetylene frequency atlas. The acetylene-stabilized laser serves as an important optical frequency standard for telecommunication applications.