Abstract: A synchronizer for synchronizing transfer over an optical link includes a frequency reference oscillator; a tracking optical timing source; a tracking comb signal; a signal processor-controller; a comb timing discriminator; a clock frequency comb; a bidirectional terminal; a time-frequency offset measurement system; and a second comb timing discriminator.

Abstract: A synchronizer for synchronizing transfer over an optical link includes a frequency reference oscillator; a tracking optical timing source; a tracking comb signal; a signal processor-controller; a comb timing discriminator; a clock frequency comb; a bidirectional terminal; a time-frequency offset measurement system; and a second comb timing discriminator.

Abstract: A condition sensing apparatus/method includes a sensor-fiber-grating that is subjected to a physical condition or measurand (strain/temperature/pressure) that is to be sensed. A broad-band light beam is directed into the core of the sensor grating, and the constructive-interference light beam that is reflected from this sensor grating is directed into a reference-fiber-grating. The reference grating is subjected to a servo-controlled elongation force or strain, and in this manner the length of the reference grating is varied until the reference grating operates to reflect a maximum intensity of its received light beam, and to transmit a minimum intensity of its received light beam. This maximum/minimum condition of the reference grating is sensed by detecting the minimum intensity of a light beam that is transmitted through the reference grating. The physical strain of the reference grating at which this condition occurs is used as a measure of the measurand to which the sensor grating is subjected.