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All-plasmonic Mach Zehnder modulator enabling optical high-speed communication at the microscale

C. Haffner, et al, All-plasmonic Mach–Zehnder modulator enabling optical high-speed communication at the microscale, Nature Photonics, 2015.


Optical modulators encode electrical signals to the optical domain and thus constitute a key element in high-capacity communication links. Ideally, they should feature operation at the highest speed with the least power consumption on the smallest footprint, and at low cost. Unfortunately, current technologies fall short of these criteria. Recently, plasmonics has emerged as a solution offering compact and fast devices. Yet, practical implementations have turned out to be rather elusive. Here, we introduce a 70 GHz all-plasmonic Mach Zehnder modulator that fits into a silicon waveguide of 10 μm length. This dramatic reduction in size by more than two orders of magnitude compared with photonic Mach Zehnder modulators results in a low energy consumption of 25 fJ per bit up to the highest speeds. The technology suggests a cheap co-integration with electronics.

a, Colourized SEM image of the MZM components. The suspended bridge enables electrical control of the device. b, Measured (symbols) and simulated (dashed lines) optical power transfer function versus applied voltage. The simulations indicate a best fit for a material with a nonlinear coefficient of 180 pm V–1.