Patent ID: 6740864
Filing Date: 2004-05-25
Classification: G02B

Abstract:
In a fiber optic transmission system that includes a plurality of inputs, outputs, and mirror switches that are selectively moveable between switched and unswitched positions in order to selectively reflect light from one or more inputs toward one or more desired outputs, an apparatus for passively monitoring whether the mirror switches are in a switched or unswitched position without significantly disrupting data transmission between the inputs and outputs comprising:a switch substrate including a first surface on which the mirror switches are disposed; a plurality of partial reflectors, disposed on the first surface of the switch substrate and positioned between the mirror switches and the outputs, for reflecting a portion of light reflected by one or more of the mirror switches when in a switched position, while allowing a portion of the light to pass therethrough toward one or more desired outputs; and a photodetector array, not attached to the first surface of the switch substrate, for sensing the portion of light reflected by the partial reflectors when one or more of the mirror switches are in the switched position, wherein light detected by a photodetector of the photodetector array indicates that a corresponding mirror switch is in a switched position relative to a desired output, and failure of the photodetector to detect light indicates that the corresponding mirror switch is not in the switched position relative to the desired output.