The invention provides a back heterogeneous integrated optical
chip and a preparation method thereof. The
chip comprises a slide glass, a
silicon optical integration layer and an electro-optical
crystal film bonded on the back surface. During preparation, a
silicon light process is firstly completed on the front surface of the SOI, the original
silicon substrate is overturned and removed after the slide glass is bonded, the electro-optical
crystal is bonded on the exposed flat back
silicon dioxide layer, and finally the electro-
optical modulator waveguide and the
metal link are processed. According to the invention, the problems of poor flatness and low bonding yield caused by a
metal structure in traditional front bonding are effectively solved, and the flatness of the silicon light back surface is fully utilized to realize high-quality heterogeneous integration. The
chip has the advantages of high integration level of silicon light and
high bandwidth and low loss of the electro-optical
crystal, and can be widely applied to a high-speed
optical communication system with a single wave of more than 400G.