The invention discloses an on-
chip mode converter based
silicon-
germanium photoelectric detection apparatus, and relates to the field of an
optical communication device. The
silicon-
germanium photoelectric detection apparatus comprises an insulating substrate, an
optical coupler, an on-
chip mode converter and a multi-mode
silicon-
germanium photoelectric
detector; the
optical coupler, the on-
chip mode converter and the multi-mode silicon-germanium photoelectric
detector are connected in sequence, and are all fixed on silicon wafers of the insulating substrate; the incident fundamental mode optical
signal is transmitted to the
optical coupler through single-mode
fiber; the fundamental mode optical
signal after being subjected to the
coupling by the optical coupler enters the on-chip mode converter; the on-chip mode converter converts the fundamental mode optical
signal into a multi-mode optical filed; the multi-mode
optical field enters the multi-mode silicon-germanium photoelectric
detector; and the multi-mode silicon-germanium photoelectric detector converts the multi-mode
optical field into an
electric signal. A germanium heavily-doped region in the silicon-germanium photoelectric detection apparatus is positioned in a region with relatively weak optical strength distribution in the multi-mode
optical field; the
absorption loss of the germanium heavily-doped region and germanium through holes on the optical field is obviously reduced, and the
responsivity of the silicon-germanium photoelectric detection apparatus can be effectively improved.