Center wavelength adjustment of silica-based arrayed waveguide gratings by glass densification

We propose and demonstrate a new method for adjusting the center wavelength of a silica-based planar lightwave circuit interferometer via the densification of silica glass. We applied the proposed method to an arrayed waveguide grating multiplexer using a hot isostatic press, and observed a large center wavelength shift of more than 1 nm. We confirmed that the wavelength shift was stable for more than 100 h at 120/spl deg/C and 90% RH.