A shot-noise limited fiber laser source by cascaded passive optical filtering

We present a technique for suppressing relative intensity noise in a fiber laser, which uses two PoundDreverHall feedback control loops to lock two optical fiber ring resonators in series. The resonators act as cascaded passive optical filters to remove high frequency intensity noise. We describe and discuss the control scheme for holding the cavities on resonance, and present the experimental result, demonstrating shot noise limited performance for intensity fluctuations above 2.5 MHz