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Photonic Integration Based on Liquid Crystals for Low Driving Voltage Optical Switches

  • Antonio d’AlessandroEmail author
  • Luca Civita
  • Rita Asquini
Conference paper
Part of the Lecture Notes in Electrical Engineering book series (LNEE, volume 546)

Abstract

This paper reports on optical waveguides using liquid crystals (LC) as core. Such optical waveguides have the advantage to be controlled by a low voltage electric field or by using an optical beam by exploiting the highly efficient electro-optic or nonlinear optical effects, respectively. Optical switches based on LC embedded in silicon grooves have been reported with on–off contrast over 40 dB by applying about 8 V. Recently, a novel technology based on LC embedded in polydimethysiloxane (LC:PDMS) have been also developed to make photonic devices based on electro-optic waveguides on flexible substrates for telecom and sensor applications. An interesting feature of this guiding structure is that propagation is polarization independent. This technology has been employed to design a 2 × 2 optical switch based on a zero-gap electro-optical controlled directional coupler able to switch light from one output port to another by applying less than 1.8 V with an extinction ratio better than 16 dB.

Keywords

Photonic devices Liquid crystals Optical switches 

References

  1. 1.
    Khoo I-C (2007) Liquid crystals, 2nd edn. Wiley, New YorkCrossRefGoogle Scholar
  2. 2.
    Asquini R, d’Alessandro A (2000) A bistable optical waveguided switch using a ferroelectric liquid crystal layer. In: Proceedings of 13th annual meeting. IEEE lasers and electro-optics Society 2000. IEEE Annual Meeting, pp 119–120, Rio Grande-Puerto Rico, USAGoogle Scholar
  3. 3.
    d’Alessandro A, Asquini R, Menichella F, Ciminelli C (2001) Realisation and characterisation of a ferroelectric liquid crystal bistable optical switch. Mol Cryst Liq Cryst 372:353–363CrossRefGoogle Scholar
  4. 4.
    Gizzi C, Asquini R, d’Alessandro A (2004) A polarization independent liquid crystal assisted vertical coupler switch. Mol Cryst Liq Cryst 421(1):95–105CrossRefGoogle Scholar
  5. 5.
    De Cort W, Beeckman J, Claes T, Neyts K, Baets R (2011) Wide tuning of silicon-on-insulator ring resonators with a liquid crystal cladding. Opt Expr 36(19):3876–3878Google Scholar
  6. 6.
    Bellini B, Larchanché J-F, Vilcot J-P, Decoster D, Beccherelli R, d’Alessandro A (2005) Photonic devices based on preferential etching. Appl Opt 44(33):7181–7186CrossRefGoogle Scholar
  7. 7.
    d’Alessandro A, Bellini B, Donisi D, Beccherelli R, Asquini R (2006) Nematic liquid crystal optical channel waveguides on silicon. IEEE J Quant Elect 42(10):1084–1090CrossRefGoogle Scholar
  8. 8.
    Donisi D, Bellini B, Beccherelli R, Asquini A, Gilardi G, Trotta M, d’Alessandro A (2010) A switchable liquid-crystal optical channel waveguide on silicon. IEEE J Quant Elect 46(5):762–768CrossRefGoogle Scholar
  9. 9.
    Asquini R, Martini L, d’Alessandro A (2015) Fabrication and characterization of liquid crystal waveguides in PDMS channels for optofluidic applications. Mol Cryst Liq Cryst 614:11–19CrossRefGoogle Scholar
  10. 10.
    d’Alessandro A, Martini L, Gilardi G, Beccherelli R, Asquini R (2015) Polarization-independent nematic liquid crystal waveguides for optofluidic applications. IEEE Photon Technol Lett 27(15):1709–1712CrossRefGoogle Scholar
  11. 11.
    d’Alessandro A, Asquini R, Chiccoli C, Martini L, Pasini P, Zannoni C (2015) Liquid crystal channel waveguides: a monte carlo investigation of the ordering. Mol Cryst Liq Cryst 619(1):42–48CrossRefGoogle Scholar
  12. 12.
    Asquini R, Fratalocchi A, d’Alessandro A, Assanto G (2005) Electro-optic routing in a nematic liquid-crystal waveguide. Appl Opt 44(19):4136–4143CrossRefGoogle Scholar
  13. 13.
    d’Alessandro A, Asquini R, Chiccoli C, Pasini P, Zannoni C (2017) Liquid crystal channel waveguides: a computer simulation of the application of transversal external fields. Mol Cryst Liq Cryst 649(1):79–85CrossRefGoogle Scholar
  14. 14.
    Yeh P, Gu C (2010) Optics of liquid crystal displays, 2nd edn. Wiley, New YorkGoogle Scholar

Copyright information

© Springer Nature Singapore Pte Ltd. 2020

Authors and Affiliations

  • Antonio d’Alessandro
    • 1
    Email author
  • Luca Civita
    • 1
  • Rita Asquini
    • 1
  1. 1.Sapienza UniversityRomeItaly

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