A Robust Low-Phase Noise Frequency Comb

Lasers with both a narrow linewidth and high long-term stability play an important role for numerous applications in various fields ranging from precision spectroscopy to preparation and control of quantum gases and atomic clocks in quantum optics. A new locking scheme combines low-phase noise by locking to an optical reference with long-term stability via a GPS disciplined RF-oscillator. Implementing a cost-effective fiber laser as optical reference (OR), the line width of each comb tooth is reduced to few kHz, providing a universal absolute reference to lock cw lasers at any wavelength accessible by the comb spectrum [1], [2].