  The squeezed cat state, an essential quantum resource, can be used for
quantum error correction and slowing decoherence of the optical cat state.
However, preparing a squeezed cat state with high generation rate, and
effectively manipulating it, remain challenging. In this work, a
high-performance all-optical in-line squeezer is developed to prepare a
squeezed cat state and manipulate the phase of the quadrature squeezing. This
scheme has the advantages that the phase of the quadrature squeezing of the
squeezed cat state can be manipulated by changing the working condition of the
squeezer, and that a higher generation rate can be achieved via the
deterministic squeezing operation of the in-line squeezer. The generation rate
of squeezed cat states reaches 2 kHz, the same as that of the initial cat
state. The all-optical in-line squeezer proposed here removes the requirements
of electro-optic and opto-electric conversions necessary for an off-line
squeezer, thus enabling high-bandwidth squeezing operations on non-Gaussian
states. These results provide an efficient method to prepare and manipulate
optical squeezed cat states, which makes a step closer to their applications in
all-optical quantum information processing.
