Triple-exposure method for fabricating triangular-lattice photonic crystals

Masatoshi Tokushima, Hideo Kosaka, Akihisa Tomita, Hirohito Yamada

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


We have developed a triple-exposure method for defining a triangular-lattice pattern to form two-dimensional (2D) photonic-crystal (PC) waveguides operating at a 1.55-μm wavelength. This method, in which three line-and-space (US) patterns are projected onto a wafer in three different directions, allows us to define a smaller-pitch triangular-lattice pattern compared to that definable by the conventional exposure method. When 0.61-μm-pitch L/S masks were employed, an i-line stepper successfully resolved a 0.7-μm-hole-pitch triangular-lattice pattern, which was at the resolution limit. A sharply bent line defect was introduced as a waveguide into the pattern by using L/S photomasks with the corresponding parts of the space areas removed. We applied this method to fabricate a triangular-lattice 2D PC with a hole pitch of 0.8 μm and a minimum feature size of 0.05 μm. The measured photonic bandgap (PBG) of this PC indicated that it operates at a near-1.55-μm wavelength.

Original languageEnglish
Pages (from-to)4236-4240
Number of pages5
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Issue number7 A
Publication statusPublished - 2000
Externally publishedYes


  • I-line
  • Lithography
  • Photonic bandgap
  • Photonic crystal
  • Triangular-lattice
  • Triple exposure
  • Waveguide

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)


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