Direct mapping of light propagation in photonic crystal waveguides

Using near-field optical microscopy, we directly map the propagation of light in the wavelength range of 1510-1560 nm along bent photonic crystal waveguides formed by removing a single row of holes in the triangular 400-nm-period lattice and connected to access ridge waveguides, the structure being fabricated on silicon-on-insulator wafers.

Based on the near-field optical images measured, we determine the bend loss to be below 2 dB in the range of 1510-1530 nm, identify the associated loss channels, and obtain an upper limit of 930 nm for the guided mode width intensity distribution at 1510 nm.