Receiver Optical Subassembly, Combo Transceiver Subassembly, Combo Optical Module, Communications Apparatus, and PON System

A receiver optical subassembly includes an optical receiving housing, and a first optical receiver, a second optical receiver, and a first glass are packaged in the optical receiving housing. The first glass is disposed obliquely relative to an optical receiving direction, and includes a light incident surface and a light emergent surface. The first optical receiver and the second optical receiver are opposite to the light emergent surface of the first glass. A first light splitting film is disposed on the light emergent surface of the first glass. A first reflective film is disposed on the light emergent surface of the first glass. The first light splitting film can transmit an optical signal of a first wavelength and reflect an optical signal of a second wavelength.