Single fiber noncritical-alignment wafer-scale optical testing

摘要

A method of determining a parameter of a wafer is disclosed. Light is propagated through a waveguide disposed in the wafer. A first measurement of optical power is obtained at a first optical tap coupled to the waveguide and a second measurement of optical power is obtained at a second optical tap coupled to the waveguide using a photodetector placed at a selected location with respect to the wafer. A difference in optical power is determined between the first optical tap and the second optical tap from the first measurement and the second measurement. The parameter of the wafer is determined from the determined difference in optical power.

主权项

1. A method of determining a parameter of a wafer, comprising:
moving the wafer to a measurement location, wherein the wafer includes a waveguide disposed therein, a first optical tap coupled to the waveguide and a second optical tap coupled to the waveguide, and the measurement location includes a photodetector having a photodetecting area having a first segment of the photodetecting area that receives light from the first optical tap and a second segment of the photodetecting area that receives light from the second optical tap when the wafer is moved to the measurement location; propagating light through the waveguide; obtaining a first measurement of optical power at the first optical tap using the first segment of the photodetecting area and a second measurement of optical power at the second optical tap using the second segment of the photodetecting area at the measurement location; determining a difference in optical power in the waveguide between the first optical tap and the second optical tap from a difference between the first measurement and the second measurement; and determining the parameter of the wafer from the difference in the optical power.