Optical field mapping using single-mode optical fibers.

A new method of measuring the complete optical field distribution (optical field mapping) is proposed and is applied to the measurement of Gaussian beam distribution at its beam waist. This method utilizes an interference technique and uses two single-mode optical fibers as flexible paths. The interference pattern caused by the output beams from the reference fiber and pickup fiber directly gives the relative phase distribution at the input end. For the intensity and phase distribution measurements the experimental ambiguity is as small as 0.1 microm and 1/10 of the wavelength, respectively. Stability of the interference fringe against the distortion of the fiber is also examined experimentally.