Improvement of the f(ceo) S/N of Er-doped fiber laser combs with super-continuum power distribution optimization

摘要

We demonstrate an Er-doped fiber comb with a significant increase of the carrier envelope offset frequency (f(ceo)) signal to noise ratio (S/N), by forcing nearly all the super-continuum (SC) power in the vicinity of the pump wavelengths to the two ends. As the wavelength and spectrum width of the pump pulse strongly affect SC power distribution, we use two steps to drive the SC power distribution to the two ends: (1) we alter the pump wavelength from 1565 nm to 1585 nm by modifying the pulse amplifier; (2) we adjust the seed pulse to decrease the FWHM of the pump pulse spectrum from 23 nm to 12 nm. As a result of our optimization, we are able to improve the f(ceo) S/N at a 300 kHz resolution bandwidth from 35 dB to 46 dB.