Japan develops 200G SiPh modulator
Researchers demonstrate a compact, low-voltage silicon modulator with built-in equalization, advancing high-speed optical interconnects for AI data centers.
Researchers from the Institute of Science Tokyo, Yokohama National University and Japan's National Institute of Advanced Industrial Science and Technology (AIST) have developed a compact slow-light silicon optical modulator capable of transmitting data at up to 200 Gbit/s, offering a potential route to faster, more energy-efficient optical interconnects.
Published in Nature Communications, the research introduces a silicon photonic modulator incorporating a built-in electro-optic equalizer to reduce reliance on external digital signal processing (DSP).
Fabricated using AIST's 300 mm silicon photonics process, the device features an active modulator core measuring just 320 µm.
The design uses a photonic crystal waveguide to slow light and enhance its interaction with silicon, enabling efficient modulation over a shorter distance.
Integrated optical delay lines and segmented phase shifters help extend bandwidth while reducing signal distortion.
In testing, the modulator achieved 180 Gbit/s using four-level pulse amplitude modulation (PAM4) without DSP equalization, increasing to 200 Gbit/s with an 11-tap digital equalizer.
It also demonstrated 140 Gbit/s on-off keying transmission with drive energy of just 26 femtojoules per bit.
The development could support next-generation photonic integrated circuits (PICs) and co-packaged optics (CPO), where compact, low-power optical components are increasingly important for AI and high-performance computing infrastructure.
However, further improvements in optical insertion loss are needed before commercial deployment.
The research highlights the potential of integrating signal equalization directly into silicon photonic devices to reduce power consumption and complexity in future high-bandwidth optical communication systems.
