We demonstrate a phase-sensitive amplifier based on a high nonlinearity graphene silicon-based hybrid waveguide. Dispersion characteristics of the phase-sensitive amplifier are adjustable via chemical potential of the graphene, and the zero dispersion point right shifts with the chemical potential increasing. Single-trench waveguide structure makes the TE mode strictly limited to the trench. The effective mode area is 0.25 mu m(2). An organic material with low two-photon absorption and high Kerr index is filled in the trench to provide a large nonlinear parameter of 3500 W-1 m(-1). The proposed amplifier has a gain of 35 dB with a length of 1.25 mm. (C) 2019 The Japan Society of Applied Physics