Sheared polymer network liquid crystal for fast-response variable optical attenuators

Yung Hsun Wu*, Yi-Hsin Lin, Yan Qing Lu, Hongwen Ren, Yun Hsing Fan, Janet R. Wu, Shin Tson Wu

*Corresponding author for this work

Research output: Contribution to journalConference article

1 Scopus citations

Abstract

A variable optical attenuator (VOA) at λ=1.55 μm using a sheared polymer network liquid crystal (SPNLC) is demonstrated. SPNLC is fabricated by mixing ∼15 wt % photo-polymerizable monomer in a LC host. To polymerize the SPNLC cell, a two-step UV curing process was adopted. Before shearing, the cell scatters light strongly, but after shearing the cell becomes highly transparent in the near IR region. Using an E7-based SPNLC, the attenuation of our VOA is rather insensitive to wavelength over the ITU C-band. The rise time and decay time were measured to be 35 μs and 205 μs, respectively, at room temperature. Such a response time is at least one order magnitude faster than the state-of-the-art nematic competitors. Comparing with other polymer-stabilized liquid crystals, the SPNLC exhibits a lower driving voltage and negligible light scattering loss in the IR spectral region. A reflection type, polarization-independent VOA with ∼240 μs response time and -32 dB dynamic range was demonstrated at room temperature and 35 V rms voltage.

Original languageEnglish
Article number59360J
Pages (from-to)1-8
Number of pages8
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume5936
DOIs
StatePublished - 1 Dec 2005
EventLiquid Crystals IX - San Diego, CA, United States
Duration: 31 Jul 20052 Aug 2005

Keywords

  • Polymers
  • Sheared liquid crystal devices
  • Variable optical attenuator

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