Single channel M x N optical fiber switch

摘要

A single channel MxN optic switch is provided in accordance with the present invention to steer light radiating from any one fiber in an input bundle into any selected fiber in an output bundle. Precision beam-steering optics is implemented using a Risley prism pair controlled by a small computer. In order to efficiently couple light between two single-mode optical fibers a low-aberration lens approximately collimates the light from the source fiber before it is passed through the Risley prisms in order to minimize the aberrations introduced by the prisms as they collectively deflect the beam through some precise angle. A second low-aberration objective lens is used to refocus the light at the core of a selected output fiber. The focusing lens transforms the angular deflection of the beam into a change in the position of the focused spot in the focal plane of the lens. In order to switch the light beam from one fiber in the output bundle to another, the Risley prisms are individually rotated about the optical axis to predetemined orientations so as to deflect the collimated light at the exact angle necessary to direct the focused spot to the core of a selected output fiber.