The working process of electro-optical crystal lithium niobate (LiNbO3) is based on the electro-optical effect, and the following is a detailed description of its working process:
Basic principle
Lithium niobate crystals belong to the triangular crystal system, 3m crystals, are negative uniaxial crystals, and their refractive index ellipsoid is a rotating ellipsoid with Z as the symmetry axis, and the cross-section perpendicular to the Z axis is a circle. When an electric field is applied to lithium niobate crystals, the refractive index of the crystals changes, which is the electro-optical effect. In the electro-optical coefficient matrix, the r33 component that is not 0 is relatively large, which is the most utilized component in electro-optical modulation, and r42 is also larger, which can be applied to polarization modulation.
Work process
- Optical signal input: When the input light wave passes through the Y beam splitter, the light wave energy is evenly distributed between the upper and lower modulation arms.
- Electro-optical effect modulation: A voltage is applied to the lithium niobate waveguide of the upper and lower modulation arms, and the refractive index of the crystal is changed by the electric field generated by the electrical signal, thereby changing the phase of the upper and lower waveguides.
- Optical signal interference: The interference of light in two beams modulated by the electro-optical effect occurs when passing through the Y-shaped beam combiner.
- Optical signal output: The interfered optical signal forms a 0-1 distribution of light intensity at the output end to achieve the purpose of modulating the light wave, and finally realize the output of the optical signal.