Reduction of Vπ voltage of an electro-optic modulator by jointly using oblique end cutting and multi-rotation

• The depth of modulation of an electro-optic modulator depends on Vπ voltage.
• Reduction of Vπ voltage helps to make the modulation practically useful.
• It is possible through the techniques of crystal end cutting and light wave multi-rotation.
• Reduction of Vπ voltage helps communication for small signal approximation.

In electro-optic crystals, the phase difference between two specific orthogonally polarized light beams can be changed by an externally applied electric field. For a certain external voltage (referred to as Vπ voltage) the phase difference between them becomes π.Several techniques for reducing the Vπ voltage of an electro-optic modulator have already been described. Here in this paper we propose that the magnitude of necessary Vπ voltage for a crystal can be reduced significantly just by cutting the extreme edge(s) of the crystal obliquely and by passing the light beam through the crystal multiple times. The paper shows analytically the reduction of Vπ voltage with the increase of the number of rotations as well as the cutting angles.