Thermally tuned optical fiber for true time delay generation

A new technique for generating a continuous range of true time delay values is introduced. Heating optical fiber in order to change the effective index of the guided mode produces time delays. A 45-m section of single-mode silica fiber is demonstrated to produce a continuous range of time delay values from 0 to 211ps over a temperature tuning range of 50°C (30-80°C). A thermal time delay factor is introduced and found to be 0.096ps/m°C for Corning LEAF fiber. A 7.66-m section of multimode Lucina polymer fiber is demonstrated to produce a range of time delay values from 0 to 32ps over a temperature tuning range of 30°C (30-60°C). The thermal time delay factor for this fiber is −0.1427ps/m°C.