APL Photonics (Nov 2019)

Fiber-integrated phase-change reconfigurable optical attenuator

  • Tiago Martins,
  • Behrad Gholipour,
  • Davide Piccinotti,
  • Kevin F. MacDonald,
  • Anna C. Peacock,
  • Orlando Frazão,
  • Nikolay I. Zheludev

Journal volume & issue
Vol. 4, no. 11
pp. 111301 – 111301-5


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We report on the experimental demonstration of an optical-fiber-integrated, nonvolatile transmission switching device. The operating mechanism exploits a cavity resonance spectral shift associated with an induced change in the refractive index of a high-index thin film on the polished side facet of the fiber. In the present case, a thermally induced amorphous-crystalline structural transition in a 500 nm layer of germanium antimony telluride at a distance of 500 nm from the core-cladding interface of an SMF-28 single-mode fiber delivers resonant transmission contrast >0.5 dB/mm at 1315 nm. Contrast is a function of active layer proximity to the core, while operating wavelength is determined by layer thickness—varying thickness by a few tens of nanometers can provide for tuning over the entire near-infrared telecoms spectral range.