Patent ID: 6990260

Claim:
An extended optical sensor comprising: a plurality of intensity-based optical point sensors spaced apart from one another at designated positions along a length of cable, each point sensor comprising: an input coupled to a respective first optical pathway conveying an optical signal to the input of said point sensor, and an output for providing an intensity modulated output optical signal indicative of a sensed environmental condition, said output of each sensor coupled to a respective second optical pathway conveying each intensity modulated output optical signal to an output end thereof; and an optical coupler having an input for receiving the intensity modulated output optical signals from each of the output ends of the second optical pathways and an output for providing an output signal indicative of the aggregate of the intensity modulated output optical signals, wherein the first and second optical pathways coupled to a respective optical sensor signal have a combined total path length that differs from the combined total path lengths of the other first and second optical pathways in accordance with the position of the associated optical point sensor to compensate for propagation delays of the optical signal through the respective optical sensor and associated first and second optical pathways such that each of the intensity modulated optical signals, upon input to the coupler, are temporally aligned with one another.