Patent ID: 6842253

Claim:
An improved structure of a Mach-Zehnder interferometer comprising: at least two multi-mode interfering beam splitters, wherein each of the multi-mode interfering beam splitters comprising: at least two input ports; at least two output ports; and a multi-mode interfering wave guide mother-area, wherein the multi-mode interfering wave guide mother-area is divided into a plurality of multi-mode interfering wave guide sub-areas, wherein the at least one multi-mode interfering wave guide sub-area is a first periodic segment wave guide having a plurality of segments; a curved arm connected to the output end and the input end between the multi-mode interfering beam splitters and the curved arm is a curved channel wave guide; and an straight arm connected to the other output end and the other input port between the multi-mode interfering beam splitters and the straight arm is a second periodic segment wave guide.