Analysis of Multimode Interference Coupler With a Width of Arbitrary-Exponent Binomial Function

Multimode interference (MMI) couplers with a width of arbitrary-exponent binomial function are proposed. The proposed structure includes the conventional, butterfly, and parabolic structure such that the proposed MMI device can be used for equal and unequal power splitting. With a proper choice of the exponent of a binomial function, several equal and unequal optical powers splitting ratio can be obtained. For comparison, the optical power splitting ratios, total transmission, and coupler length of the proposed MMI couplers are discussed.