Аннотация:Broadband multidimensional variational measurement allows overcoming the standard quantum limit (SQL) indetecting a classical mechanical force acting on a mechanical oscillator. In this measurement quantum back action,which perturbs the evolution of a mechanical oscillator, can be completely removed in a broad frequency band afterpost-processing. In this paper we show that optical losses inside the cavity restrict back action exclusion due to theloss noise. We also analyze the effect of two-photon (nondegenerate) and conventional (degenerate) squeezing inorder to improve sensitivity with accounting for optical losses. We consider mainly internal squeezing.
