GI-core polymer parallel optical waveguide with high-loss, carbon-black-doped cladding for extra low inter-channel crosstalk

Hisashi Uno, Takaaki Ishigure

Research output: Contribution to journalArticle

4 Citations (Scopus)


Graded-index (GI) polymer parallel optical waveguides with high-absorption, carbon-black-doped cladding are fabricated using the preform method in order to reduce the inter-channel crosstalk. The waveguides exhibit a lower inter-channel crosstalk (<-69.3dB) than optically-transparent-clad waveguides (∼-33.7 dB) and maintain low propagation loss (0.029dB/cm). We characterize the waveguides with different concentration of carbon black in order to confirm the required concentration (required absorption loss) for keeping the inter-channel crosstalk low enough. In addition, carbon-black-doped waveguides are fabricated directly on a substrate by means of a soft-lithography method. Crosstalk is sufficiently decreased despite the high scattering loss of the core material, while insertion loss is not increased. Furthermore, we fabricate a waveguide with a high-scattering-loss cladding to confirm the origin of low crosstalk in carbon-black-doped waveguides. We confirm that high scattering loss of cladding is not necessarily as effective for crosstalk reduction as high absorption loss of cladding.

Original languageEnglish
Pages (from-to)10931-10939
Number of pages9
JournalOptics Express
Issue number11
Publication statusPublished - 2011 May 23


ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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