Low-loss waveguide crossing using a multimode interference structure

Heliang Liu, Hwa Yaw Tam, Ping Kong Alexander Wai, Edwin Pun

Research output: Journal article publicationJournal articleAcademic researchpeer-review

68 Citations (Scopus)


A novel design technique for low-loss waveguide crossing using the self-imaging properties of multimode interference (MMI) structures is presented. The technique exploits the observation that optical fields with a small lie width relative to that of the MMI structure in the image reformed region experience negligible propagation loss even in the absence of lateral guiding mechanism around the region. This allows the introduction of a slab in the MMI region. The technique could also be used to design planar light-wave circuits with small wavelength-dependent loss which is important for DWDM devices. Using two-dimensional wide-angle BPM simulations, taper width technology and MMI structure technology is compared for low-loss slab propagation in orthogonal intersection. We also demonstrate that low-loss crossing waveguides with intersection angle as small as 23° can be achieved with the aid of MMI structures.
Original languageEnglish
Pages (from-to)99-104
Number of pages6
JournalOptics Communications
Issue number1-3
Publication statusPublished - 1 Nov 2004


  • BPM simulations
  • Integrated-optical
  • Low-loss slab propagation
  • MMI
  • Multimode interference
  • Optical waveguides
  • Self-imaged properties
  • Waveguides

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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