An ultralow power athermal silicon modulator

Silicon photonics has emerged as the leading candidate for implementing ultralow power wavelength–division–multiplexed communication networks in high-performance computers, yet current components (lasers, modulators, filters and detectors) consume too much power for the high-speed femtojoule-class links that ultimately will be required. Here we demonstrate and characterize the first modulator to achieve simultaneous high-speed (25 Gb s(−1)), low-voltage (0.5 V(PP)) and efficient 0.9 fJ per bit error-free operation. This low-energy high-speed operation is enabled by a record electro-optic response, obtained in a vertical p–n junction device that at 250 pm V(−1) (30 GHz V(−1)) is up to 10 times larger than prior demonstrations. In addition, this record electro-optic response is used to compensate for thermal drift over a 7.5 °C temperature range with little additional energy consumption (0.24 fJ per bit for a total energy consumption below 1.03 J per bit). The combined results of highly efficient modulation and electro-optic thermal compensation represent a new paradigm in modulator development and a major step towards single-digit femtojoule-class communications.