Abstract: A system and method of estimating a distance between the distal end of an optical fiber and treated tissue, to improve treatment efficiency, is provided herein. The estimation is achieved by modulating the numerical aperture of a light beam transmitted through the fiber to receive reflections from the tissue and distinguish them from other reflections in the fiber, and further by calculating the distance by comparing reflection intensities of beams having different numerical aperture values that illuminate the tissue over a very short period, so that tissue and environment conditions do not change much. Distance estimation may be carried out by modulating the treatment beam itself, or by a light beam transmitted between pulses of a pulsed treatment beam.

Abstract: A system and method of estimating a distance between the distal end of an optical fiber and treated tissue, to improve treatment efficiency, is provided herein. The estimation is achieved by modulating the numerical aperture of a light beam transmitted through the fiber to receive reflections from the tissue and distinguish them from other reflections in the fiber, and further by calculating the distance by comparing reflection intensities of beams having different numerical aperture values that illuminate the tissue over a very short period, so that tissue and environment conditions do not change much.

Abstract: A method for detecting and measuring physical perturbations sensed by a multi-mode waveguide, through which a number of modes of a coherent electromagnetic wave propagates through and exit from. The method comprises irradiating the exiting electromagnetic wave on one or more two-dimensional sensing arrays comprising a plurality of sensing elements that are sensitive to the irradiated electromagnetic wave; determining, simultaneously, in a parallel manner, absolute values of sensed changes across different zones of the two-dimensional sensing arrays, each zone comprising one or more sensing elements; and summing the absolute values of different groups of different zones to obtain a representation of the perturbations.