Long-period gratings in polymer ridge waveguides

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)22_Publication in policy or professional journal

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Original languageEnglish
Article number60
Pages (from-to)395-404
Journal / PublicationProceedings of SPIE - The International Society for Optical Engineering
Publication statusPublished - 2005


TitleOptoelectronic Devices and Integration
Period8 - 11 November 2004


In this paper, we report the design and fabrication of a long-period waveguide grating (LPWG) in a polymer ridge waveguide, which has a benzocyclobutene (BCB) core and an epoxy cladding of the same width. We first apply an accurate perturbation theory to evaluate the phase-matching condition of the grating and derive simple analytical expressions to highlight the temperature dependence of the resonance wavelength. The possibility of achieving a polarization-independent resonance wavelength is also discussed. We next describe the fabrication of an LPWG in a BCB/epoxy ridge waveguide by a UV-writing technique using a KrF excimer laser and present the transmission spectra of the grating measured at different UV dosages. By controlling the waveguide width, we produce an LPWG with a resonance wavelength that is polarization insensitive at a specific temperature. The temperature dependence of the LPWG is also discussed. Our results provide a better understanding of the operation principle of LPWGs, which should facilitate the design of LPWG-based devices for various applications.

Research Area(s)

  • Long-period gratings, Optical filters, Optical waveguide filters, Polymer waveguides, Ridge waveguide, Tunable filters