DQPSK (Differential Quadrature Phase Shift Keying) demodulation device

Abstract

The invention discloses a DQPSK (Differential Quadrature Phase Shift Keying) demodulation device. The demodulation device comprises a substrate, a first coupler, a second coupler, a third coupler, a first Mach-Zehnder interferometer and a second Mach-Zehnder interferometer; an output power ratio of a first output end of the first coupler to a second output end of the first coupler is 1:1, the first output end of the first coupler is connected with the first Mach-Zehnder interferometer, and the second output end of the first coupler is connected with the second Mach-Zehnder interferometer; and the first Mach-Zehnder interferometer comprises a first fixed arm and a first cantilever, the output end of the first cantilever is connected with the input end of the second coupler, the second Mach-Zehnder interferometer comprises a second fixed arm and a second cantilever, and the output end of the second cantilever is connected with the input end of the third coupler. According to the DQPSK demodulation device, by controlling light, conversion of a phase of signal light is implemented, so that DQPSK demodulation is implemented; and the DQPSK demodulation device is accurate to demodulate and simple to control.

Description

technical field [0001] The invention belongs to optical signal demodulation technology, and more specifically relates to a demodulation device of differential quadrature phase shift keying. Background technique [0002] Differential Quadrature Phase Shift Keying (DQPSK), as a quadrature phase modulation format, doubles the bit rate compared with the traditional binary amplitude keying (OOK) modulation method, and has higher spectral efficiency and very narrow spectral width . In the case of the same symbol rate, the system capacity of DQPSK is twice that of relative phase shift keying (DPSK), and it has natural anti-nonlinear resistance, dispersion tolerance and polarization mode tolerance. Using a balanced receiver at the receiving end can improve the sensitivity by about 3dB on this basis, thereby greatly improving the transmission performance. [0003] The demodulation method of the DQPSK signal generally adopts the balanced detection method, that is, two Mach-Zehnder i...

AI Technical Summary

Problems solved by technology

Since the device requires an additional voltage electrode to inject current into the lower arm of the Mach-Zehnder interferometer to change its phase shift, it requires additional power to supply energy to the voltage electrode, and also increases the size of the demodulation device

At the same time, the pressurization of the lower arm will generate heat, which will affect the refractive index of other waveguides, causing unnecessary crosstalk and affecting the accuracy of the demodulation device.

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