Abstract: A 3×3 multi-mode interference coupling device having a length L and a width W, a center input port between a pair of outer input ports, where each outer input port is displaced from the center input port by a distance W/3, and a center output port between a pair of outer output ports, where each outer output port is displaced from the center output port by a distance W/3, where the device is supports Cbar, Ccen, and a Cx coupling coefficients therein, when the outer input ports are equally excited with an input signal having a 180° phase difference, Ccen from each outer input port destructively interferes when the propagation length L is an integer number of L?/2, where the device outputs equal intensity laser modes from each outer output port when the propagation length is an integer multiple of L?/2.

Abstract: A 3×3 multi-mode interference coupling device having a length L and a width W, a center input port between a pair of outer input ports, where each outer input port is displaced from the center input port by a distance W/3, and a center output port between a pair of outer output ports, where each outer output port is displaced from the center output port by a distance W/3, where the device is supports Cbar, Ccen, and a Cx coupling coefficients therein, when the outer input ports are equally excited with an input signal having a 180° phase difference, Ccen from each outer input port destructively interferes when the propagation length L is an integer number of L?/2, where the device outputs equal intensity laser modes from each outer output port when the propagation length is an integer multiple of L?/2.