A pm-qpsk integrated optical modulator based on lithium niobate and its working method

Abstract

The invention relates to a lithium niobate-based PM-QPSK integrated light modulator and a working method thereof. The lithium niobate-based PM-QPSK integrated light modulator comprises an upper electrode, a lower electrode, a lining and lithium niobate crystals, wherein a polarization demultiplexer, two IQ modulators in parallel and a polarization multiplexer are sequentially etched on the lithium niobate crystals in a light path direction; the upper electrode and the lower electrode are respectively arranged on the upper surface of the lithium niobate crystals and below the lining; the polarization demultiplexer and the polarization multiplexer are respectively a lithium niobate polarization demultiplexer based on MZI and a lithium niobate polarization multiplexer based on MZI. As the lithium niobate-based PM-QPSK integrated light modulator is provided with the lithium niobate polarization demultiplexer and the lithium niobate polarization multiplexer manufactured on a birefrigent effect of lithium niobate, the conventional method that a polarization multiplexer is manufactured on the basis of a silicon substrate is changed, a polarization demultiplexer and a polarization multiplexer based on the silicon substrate and IQ modulators are integrated on the same piece of crystal, and the allowance is far smaller than a silicon substrate process.

Description

technical field [0001] The invention relates to a PM-QPSK integrated optical modulator based on lithium niobate and a working method thereof, belonging to the technical field of optical modulators. Background technique [0002] The optical modulator is a key device for high-speed, short-distance optical communication and one of the most important integrated optical devices. There are four types of external modulators in general optical fiber communication systems: acousto-optic (AO) modulators, magneto-optic modulators, electro-optic (EO) modulators and electro-absorption (EA) modulators. Among them, the electro-optic modulator, which depends on the change of the light-carrying mode of a certain planar waveguide, is one of the two main types of modulators used in modern optical fiber systems. [0003] Lithium niobate thin film materials have excellent physical properties such as electro-optic, nonlinear optics, and acousto-optic, and have potential advantages for optoelectr...

AI Technical Summary

Problems solved by technology

The traditional IQ modulator needs to achieve a phase difference of π / 2 between the upper and lower channels. There are usually two methods. One is to control the phase delay of the upper and lower channels by controlling the length difference between the upper and lower waveguides. The phase delay requires a process tolerance of about 0.3 microns, which is quite difficult to manufacture. The second is to change the refractive index of the waveguide by adding electrodes to change the optical path difference between the upper and lower channels to achieve the effect of π / 2 phase delay between the upper and lower channels. but this makes the device more complex

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