Sensitivity enhancement of a mode-locked ring laser gyroscope by giant intracavity dispersion

It has been theoretically predicted that giant intracavity dispersion can significantly alter the response of a ring laser gyroscope. We demonstrate this effect experimentally in a mode-locked ring laser. Group velocity dispersion of this magnitude can only be the resonant dispersion due to the Kramers-Kronig relation. Although the bandwidth of this large dispersion is rather small, inserting a Fabry-Perot interferometer into the cavity provides positive dispersion (resulting in ”slow light”) to all components of the frequency comb. We show that this is due to the the Fabry-Perot comb coupling to the laser resonator comb. Increasing the sensitivity of the gyroscope would require a large negative dispersion (resulting in ”fast light”) in the cavity. This can be achieved using a Gires-Tournois-interferometer.