Compact gradual bends for channel plasmon polaritons.

We report the design, fabrication and characterization of compact gradual bends for channel plasmon polaritons (CPPs) being excited at telecom wavelengths. We obtain high-quality near-field optical images of CPP modes propagating along a bent V-groove in gold, which indicate good CPP mode confinement in the groove and efficient guiding around the compact S-bend connecting two 5-mum-offset grooves over a distance of 5 mum. Using averaged cross sections of the CPP intensity distributions before and after the S-bend, the total bend loss is evaluated and found to be close to 2.3 dB for the wavelengths in the range of 1430-1640 nm.