Design of a Multimode Fixed Optical Coupler using Simplified Formula

Abstract

A theoritical design has been done for the multimode fiber coupler based on the Ogawa's (2) formula. The optimum coupling length has been calculated based on the numerical aperture. We suggest, that to design a coupler of a given coupling efficiency, the numerical aperture be varied keeping a fixed coupling length. This can be done by varying the refractive index of the cladding. A design has been proposed accordingly.

Indexing terms:

• Multimode fibre coupler
• Coupling efficiency
• Numerical aperture
• Refractive index