TOKYO - August 12, 2025 - NTT has successfully demonstrated long-haul, high-capacity optical transmission at 160 terabits per second over distances exceeding 1,000 km. This was made possible by applying a transmission design that effectively utilizes nonlinear effects within the optical fiber. In this experiment, we applied a newly developed wavelength band. Optical circuit switching technology emerged in the 1970s as a fundamental solution for managing optical signals without electrical conversion. The technology enables direct routing of optical signals through mechanical, micro-electromechanical systems (MEMS), or liquid crystal-based switching. Enter the QSFP28-100G-ZR4 transceiver – a powerhouse module designed to bridge vast distances with clarity and reliability. Long-distance variants, typically referred to as LX, EX, ZX, or ER/LR SFPs, are engineered with higher optical power budgets and longer wavelength.
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