We describe a low-loss single-mode waveguide in planar light-wave circuit (PLC) glass doped with boron and phosphorus, which is more difficult to write than pure-silica glass. The written waveguide has a rectangular core, a symmetric near-field pattern, and a propagation loss of . The loss that originates from the mode-field mismatch between the mode-field diameters of the written and the PLC waveguides is less than . In addition, we successfully connected PLC waveguides with a -long waveguide written with a laser. The laser-written waveguide can flexibly connect PLC waveguides with a low coupling loss.
© 2005 Optical Society of AmericaFull Article | PDF Article