Highly efficient, ultrafast optical-to-electrical converter and method of operating the same

摘要

The periodic array of photodiodes are disposed in a passive optical waveguide electrically coupled in series with each other by microwave transmission line. The collective array of photodiodes coupled to the optical waveguide and microwave transmission line results in an increased bandwidth-efficiency product for the photodetector array as compared to any single photodetector within the array. High optical-to-electrical conversion efficiencies near unity are achieved at frequencies as high as several hundred GHz. High efficiencies are achieved by matching the group velocity of the optical waves within the optical waveguide with the group velocity of electrical signals being transmitted in the microwave transmission line by appropriate selection of the capacitance of each of the photodiodes. Power saturation is improved by decreasing the optical density within the active layer of the photodiodes. Optical coupling efficiencies from optical fibers into and from the optical waveguide are further improved by enlarging the optical mode size in the optical waveguide.