Surface plasmon polariton based modulators and switches operating at telecom wavelengths

We report design, fabrication, and characterization of thermo-optic Mach–Zender interferometric modulators and directional-coupler switches whose operation utilizes the long-range surface-plasmon-polariton waveguiding along 15-nm-thin and 8-μm-wide gold stripes embedded in polymer and heated by electrical signal currents. The devices are characterized at the light wavelength of 1.55 μm, featuring low driving powers ($<10\mathrm{mW}$ for modulators and $<100\mathrm{mW}$ for switches), high extinction ratios ($>30\mathrm{dB}$ ), moderate response times $(\sim 1\mathrm{ms})$ , and the total (fiber-to-fiber) insertion loss of $\sim 13\mathrm{dB}$ (for modulators) and $\sim 11\mathrm{dB}$ (for switches) when using single-mode fibers.