Optical-difference four-phase shift keying modulator with nested Mach-Tsend waveguide structure

A optical differential four phase-shift keying modulator nesting with Mach-Zehnder waveguide structure comprising precoder, laser, separator and coupler, two nested Mach-Zehnder type interference type structure modulator. The output of precoder separately connects two Mach-Zehnder type interference type structure modulators; laser, separator, nested Mach-Zehnder type interference type structure modulator and coupler connect in turn. Nested Mach-Zehnder type interference type structure modulator is constituted by the first Mach-Zehnder type interference type structure modulator nesting inside of second Mach-Zehnder type interference type structure modulator. In the invention, the inventive device is obviously shortened in length thereby reducing processing difficulty, notably promoting finished product rate and product performance, reducing light branch spoilage and production cost.