We present an experimental demonstration of fiber laser noise suppression by the mode cleaner.The intensity noise of a single frequency fiber laser is suppressed near the shot noise limit after a sideband frequency of 3 MHz.Two series mode cleaners are used to improve the noise suppression.The noise reduction is over 27 dB at 3 MHz.
Spatial quantum optics and quantum information based on the high order transverse mode are of importance for the super-resolution measurement beyond the quantum noise level. We demonstrated experimentally the transverse plane TEM01 Hermite-Gauss quantum squeezing. The squeezed TEM01 mode is generated in a degenerate optical parametric amplifier with the nonlinear crystal of periodically poled KTiOPO4. The level of 2.2-dB squeezing is measured using a spatial balance homodyne detection system.
