The transmission of one dimensional image through a single fibre is carried out by both spatial multiplexing method and frequency multiplexing method.
Transmission of two dimensional image is also carried out by using planar fibre bundle (parallel frequency multiplexing) and/or a single fibre which scans the intermediate signal along the direction of the entrance slit(serial frequency multiplexing).
The resolution limits of these methods are obtained experimentally and compared with the theoretical values. In spatial multiplexing the theoretical value is 50 μ which is equal to the core diameter of the fibre used, however experimental resolution limit is found to be 1 mm. In frequency multiplexing the experimental resolution limit is 0.1 mm(twice of the core diamer), which agrees with the value predicted theoretically.
The reason that the spatial multiplexing method gives the resolution limit far poor than the theoretical expectation is attributed to the internal inhomogeneity of the optical fibre and the difficulty in aligning horigentally the fibre accurately enough along the optical axis.
In present work it is found the image transmission by frequency multiplexing is useful indeed in practical optical communication, however the spatial multiplexing has still many aspects to be resolved before any practical use.
