US Patent 9804334 Fiber to chip optical coupler

An optical coupler for coupling an optical fiber to a photonic integrated circuit (PIC) is presented. The optical coupler comprises a first curved mirror included in a first substrate layer of the PIC and at a first predefined lateral distance from an optical transceiver associated with the PIC; a second curved mirror included in a second substrate layer and placed at a second predefined lateral distance from the optical fiber; and a spacer located between the first substrate layer and the second substrate layer.