Reduction of Optical Fiber Loss and Signal Scattering Using Marcuse’s Method

Abstract

The major problem related to Optical Fibre cable is micro and macro bending. Micro bending is a result of imperfection during the manufacturing process of Optical fibre. However, in this research, emphasis is on macro bending caused by external bending of Optical Fibre cables during Installation, resulting to loss of signal or outright mechanical damage of the Optical fibre. In order to reduce loss and signal scattering due to bending in Optical Fibre, we introduced the Marcuse's method, and performed bending experiments for several bending radius on both the Multi-Mode and Single-Mode Optical Fibres to determine the loss. Comparative analysis of the results from the various degrees of bending was done. MATLAB was used to perform simulations of bending at a wavelength of 1550nm to determine the loss in dB. Signal loss due to distance and the number of turns of Optical Fibre to signal loss experiments were performed. Comparative analysis of the result from two methods: Marcuse's and U-bending methods was carried out and it was observed that critical bending of the U-bending method tends to zero and near mechanical failure. Critical bends between 3mm and 8mm resulted to high signal loss ranging from 1.32dB to 12.45dB for Multi-Mode Optical Fibre and 0.03db to 6.33dB for Single-Mode Optical Fibre, while curvatures of 9.5mm up to 10mm was 0.65dB and 0.53dB. The Multi-Mode Fibre experienced more signal loss compared to the Single-Mode Fibre. It was observed that the number of turns of Optical Fibre cable impacts on the bending as higher turns of Optical Fibre cables experienced greater signal loss. The results of macro bending losses were achieved by series of measurements carried out in the investigations. Finally, experimenting with different types of fibers is crucial for identifying bending limits. There is a considerable increase in bending loss when the bending radius is less than the critical bending radius.