An integrated Mach-Zehnder interferometric sensor fabricated by using Cr mask extension lithography

Sung Joong Choo, Jung Ho Park, Sangyoup Lee, Hyun Joon Shin

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


An integrated Mach-Zehnder interferometric chip operating at 632. 8 nm was designed and fabricated using planar rib waveguide technology for optical sensor applications. A rib waveguide with a silicon-oxynitride core layer and silicon-oxide clad layers was geometrically designed to have a singlemode operation and a high surface sensitivity by using an effective index method. A chromium mask layer was employed as an etch stop to protect the core layer of the rib waveguide and was patterned using an image reversal process with a photo mask applied to the sensor zone. The image reversal process was modified in order to obtain a longer chromium mask layer against the sensor zone. We have, therefore, established a fabrication method for an integrated Mach-Zehnder interferometric sensor without the addition of a new photo mask. The optical measurement with this device for a mixture of deionized water (DIW) and phosphate buffer solution (PBS) finally showed a sensitivity of about π/(6.25 × 10 -4).

Original languageEnglish
Pages (from-to)744-749
Number of pages6
JournalJournal of the Korean Physical Society
Issue number5
Publication statusPublished - 2012 Mar


  • Chromium mask layer
  • Image reversal process
  • Mach-Zehnder interferometric chip
  • Rib waveguide
  • Silicon-oxynitride

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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