Tailoring temperature response for a multimode fiber

This work introduces special states for light in multimode fibers featuring strongly enhanced or reduced correlations between output fields in the presence of environmental temperature fluctuations. Using experimentally measured multi-temperature transmission matrix, a set of temperature principal modes that exhibit resilience to disturbances caused by temperature fluctuations can be generated. Reversing this concept also allows the construction of temperature anti-principal modes, with output profiles more susceptible to temperature influences than the unmodulated wavefront. Despite changes in the length of the multimode fiber within the temperature-fluctuating region, the proposed approach remains capable of robustly controlling the temperature response within the fiber. To illustrate the practicality of the proposed special state, a learning-empowered fiber specklegram temperature sensor based on temperature anti-principal mode sensitization is proposed. This sensor exhibits outstanding superiority over traditional approaches in terms of resolution and accuracy. These novel states are anticipated to have wide-ranging applications in fiber communication, sensing, imaging, and spectroscopy, and serve as a source of inspiration for the discovery of other novel states.