Research Of The Phase Modulation Tecnnics Based On The Electro-optic Effect In Lithium Niobate

Lithium niobate(LN)is one of the most excellent electro-optic materials in the world,and the spatial light modulators that based on LN are always the research hotspots,this kind of modulators can be used to modulate the amplitude or phase of light beam,and compared with the traditional liquid crystal spatial light modulators,LN modulators may have faster response speed and better endurance of light intensity.The technology of miniaturized,compact LN modulators has matured rapidly during the past few decades,LN modulators may bring great innovations to a variety of applications in high performing computing,digital & analog telecommunication links and data centers and so on.Several common types of spatial light modulators are summarized at the beginning of this letter,then we discussed the fundamental properties of LN and theory of electro-optic effect.A basic classification and the application of phase modulators that based on the electro-optic effect of LN are introduced.This paper mainly introduced two kinds of electro-optic phase modulators,the first one is assisted by the ultrahigh-order guided modes(UOMs)in the symmetrical metal-cladding waveguide(SMCW)and the electro-optic effect of LN,another is a one-dimensional,multi-channel,high speed spatial light modulator based on the electro-optic effect of LN.We first described the related theory of SMCW,these provide the theoretical basis for the following contents.Later,the detail of the first electro-optic modulator has been demonstrated,due to the high sensitivity of the UOMs,the required voltage for a 2? phase shift can be reduced dramatically.This modulator bases on the longitudinal electro-optic effect.The second kind of electro-optic modulator is a one-dimensional,multi-channel,high speed spatial light modulator based on the transverse electro-optic effect of LN.Compared with the phase modulator assisted by UOMs,it requires lower voltage and has many pixels,as a result,it can perform a spatial phase modulation for one or maybe more dimensions.Until now 8-channels and 16-channels modulators have been fabricated,which laid a good foundation for receiving a MHz response speed,128-channels phase modulator.