Beam splitter and quantum light source

The invention discloses a beam splitter and a quantum light source. An input waveguide section of the beam splitter extends from a first direction to a second direction, and the refractive index of the input waveguide section in the second direction is greater than that in the first direction; the widths of the first separation waveguide section and the second separation waveguide section are reduced along the propagation direction of input light waves; the first output waveguide section and the second output waveguide section extend from the second direction to the first direction; the second coupling waveguide section and the first coupling waveguide section are arranged at an interval. The TE polarization fundamental mode in the input light wave can efficiently pass through the first separation waveguide section and the first output waveguide section, and the TE polarization high-order mode converted by the TM polarization fundamental mode in the input light wave can efficiently penetrate through the first