Modern integrated photonics demands compact, high-speed modulators capable of efficiently controlling optical signals. Silicon platforms offer high integration density, but achieving high-speed modulation on silicon faces limitations. Moreover, many applications (e.g., balanced detection schemes) require two complementary (phase-inverted) signals. Traditional solutions such as Mach–Zehnder interferometers are bulky and complex to manufacture.
In a new paper published in Light: Advanced Manufacturing , a team of scientists, led by Professor Vladimir P. Drachev from Plasmonics Laboratory, Center for Engineering Physics, Skolkovo Institute of Science and Technology, Russia and co-workers have developed a hybrid plasmonic modulator based on Si-ITO-SiO₂-Au. Its key feature is the use of a multimode silicon waveguide 7 µm wide and 220 nm thick. Unlike conventional single-mode devices, several transverse magnetic (TM) modes are excited simultaneously. Their interference at the output creates two spatially separated channels with a precise π phase shift. This yields two inverted signals within a single waveguide and a single grating coupler, eliminating the need for bulky interferometers.
Modulation is achieved by changing the electron concentration in a 2 nm-thick ITO accumulation layer upon voltage application. Depending on the position of the input optical fiber, the device can operate in either amplitude‑dominant or phase‑dominant modulation regime.
Key Features and Parameters
These results represent a major step forward in integrated photonics, enabling compact, high‑speed optical links with balanced signal routing for data centers, telecommunications, and microwave photonics.
This work was supported by the Russian Science Foundation (Grant No. 25‑72‑31023).
Light: Advanced Manufacturing
Advantages of multimode Si-ITO electro-optical modulators for balanced signal routing