An Electrically Tunable Liquid Crystal Lens for Fiber Coupling and Variable Optical Attenuation

Yi Hsin Lin

doi:10.4172/2332-0796.1000124

Abstract

An electrically tunable Liquid Crystal (LC) lens for both of fiber coupling and variable optical attenuation is demonstrated. The LC lens modulates the beam waist coupling to the fiber by electrically changing the lens power. When the modulated beam waist is close to the core size of the fiber, the LC lens is operated as a lens coupler. When the beam waist increases by reducing the lens power, the LC lens is operated as a Variable Optical Attenuator (VOA) as a result of the corresponding coupling coefficient variation of the transformed beam into a multimode fiber. The study provides a way to design an optical device for fiber coupling and variable optical attenuation based on electrically tunable focusing optical component.

Highlights

Variable Optic Attenuators (VOAs) are indispensable components for optical power control in the applications of telecommunication systems, high speed data networks and optical sensor systems
Based on Eq (1), Planar Lightwave Circuits (PLC) can be rewritten as 8×N×λ/D2, where N is the number of concentric rings, λ is the operating wavelength, Δn×dLC equals N×λ, and D is the aperture size of the Liquid Crystal (LC) lens
The beam waist coupling to the fiber can be controlled by adjusting the lens power of the LC lens

Summary

Introduction

Variable Optic Attenuators (VOAs) are indispensable components for optical power control in the applications of telecommunication systems, high speed data networks and optical sensor systems. Several scattering-type VOAs have been proposed to reduce the input power by using polymerstabilized liquid crystals [6,7,8] All these developed VOAs based on LC still require a lens coupler to couple the light into the fiber when applied to the fiber-connected optical systems. Eq (3), the coupling efficiency is determined by the incident beam waist (w), which can be continuously controlled by the electrically tunable lens power of the LC lens. The mechanism illustrated above is applicable for either LC lenses with different structures or any tunable focusing devices whose lens power can be adjusted continuously from positive mode to negative mode

Experiments and Discussions

Conclusion