  Optical Schrodinger's cat (SC) is highly anticipated because of the potential
of realizing fault-tolerant quantum computing, but the practical merit is only
shown when the amplitude is larger than 2. However, such high-amplitude cats
have not been prepared due to the limitations rooted in the existing method.
Here, we demonstrate a principle that a large SC-like state can be generated by
the superposition of two kittens in which two nearby coherent states interfere
and grow to an enlarged coherent-like state. Further, we propose a scheme to
breed the cat beyond the limitation in the former works with a high probability
by realizing the superposition of two SCs in coupled waveguides. The principle
and scheme demonstrated here provide a new perspective on understanding quantum
superposition in phase space and a better solution for the efficient generation
of SCs on chips.
