Photonic crystal waveguide,
QUEP simulations of 90 degree bends with the following specification: background refractive index nb = 1.0, refractive index of square rods nr = 3.4, rod width r = 0.15 µm, period of the photonic crystal p = 0.6 µm, refractive index of conventional port cores ng = 1.8, width of the port waveguides w = 0.5 µm, Nr = 4 rows of rods enclose the photonic crystal channel. All calculations are meant for TE polarization, i.e. Ey is the single nonvanishing component of the electrical field.  

Wavelength dependence of the transmission:
The bend configuration is excited at the bottom by the guided mode of the vertical core. PR and PT are the relative guided power fractions that are reflected and transmitted, respectively. Note that the simulations include the two transitions between the conventional slab waveguides and the waveguide established by the photonic crystal. The links at the positions indicated by the the blue tick marks lead to illustrations of the time dependent electric field.

1.461 µm 1.551 µm

The parameters for these simulations were adopted from
R. Stoffer, H.J.W.M. Hoekstra, R.M. de Ridder, E. van Groesen, and F.P.H. van Beckum, Numerical studies of 2D photonic crystals: Waveguides, coupling between waveguides and filters, Optical and Quantum Electronics 32, 947--961 (2000).
See also the references cited in that paper.