Seren Juno and Ribbon Achieve 20Tbps Transmission on 10,000 km JUNO Trans-Pacific Cable

PLANO, Texas, Nov. 12, 2025 /PRNewswire/ -- Ribbon Communications Inc. (Nasdaq: RBBN), a global leader in real-time communications technology and IP optical networking solutions, today announced the successful completion of a 20Tbps optical transmission field trial on the 10,000 km JUNO trans-Pacific submarine cable, developed and operated by Seren Juno. Ribbon's mission is to help service providers, enterprises and critical infrastructure operators worldwide modernize and secure their networks and services.

Set to become the largest trans-Pacific cable system between Japan and the U.S., JUNO will deliver more than 350Tbps of total capacity across 20 fiber pairs, supporting growing global demand for high-speed connectivity.

"This is a significant milestone in long-haul optical networking, confirming the feasibility of transmitting 20 terabits per second per fiber pair," said Sam Bucci, Ribbon EVP and COO, Ribbon. "Our Apollo platform's ability to deliver 20Tbps over 10,000 km showcases the scalability and robustness of Ribbon's technology for next-generation global connectivity."

"Achieving results that rival those of leading competitors gives us confidence that this could become one of our new strategic options," said Yoshio Sato, CEO, Seren Juno.

The trial featured Ribbon's Apollo 9408 transponder, powered by advanced 5nm 140GBaud technology, and the Apollo 9608 platform, which integrates submarine-grade optical line system functions. The Apollo 9408 supports flexible modulation from 400Gbps to 1.2Tbps per wavelength, enabling performance optimization tailored to cable conditions. Combined with the compact, low-power Apollo 9608, Ribbon sets a new benchmark for submarine optical transmission.

About Ribbon
Ribbon Communications (Nasdaq: RBBN) delivers secure cloud communications and IP and optical networking solutions to service providers, enterprises and critical infrastructure sectors globally. We engage deeply with our customers, helping them modernize their networks for improved competitive positioning and business outcomes in today's smart, always-on and data-hungry world. Our end-to-end portfolio of communications software and IP Optical networking solutions delivers superior value and innovation by leveraging cloud-native architectures, automation and analytics tools, and leading-edge security. We maintain a keen focus on our commitments to Environmental, Social, and Governance (ESG) matters, offering an annual Sustainability Report to our stakeholders. To learn more about Ribbon, please visit rbbn.com

Important Information Regarding Forward-Looking Statements
The information in this release contains forward-looking statements regarding future events that involve risks and uncertainties. All statements other than statements of historical facts contained in this release, including those regarding the expected benefits from use of Ribbon Communication's products, are forward-looking statements. The actual results of Ribbon Communications may differ materially from those contemplated by the forward-looking statements. For further information regarding risks and uncertainties associated with Ribbon Communications' business, please refer to the "Risk Factors" section of Ribbon Communications' most recent annual or quarterly report filed with the SEC. Any forward-looking statements represent Ribbon Communications' views only as of the date on which such statement is made and should not be relied upon as representing Ribbon Communications' views as of any subsequent date. While Ribbon Communications may elect to update forward-looking statements at some point, Ribbon Communications specifically disclaims any obligation to do so.

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About Seren Juno Network Co., Ltd.

Established in July 2022 as a joint venture between NTT Ltd. Japan Corporation, Mitsui & Co., Ltd., PC Landing Corp., and JA Mitsui Leasing, Ltd., Seren Juno Network Co., Ltd. is the owner and operator of the JUNO submarine cable system. JUNO is a next-generation trans-Pacific cable spanning approximately 10,000 km between Japan and the United States, featuring 20 fiber pairs (40 optical cores) and a design capacity of up to 350 Tbps. Seren Juno's mission is to provide secure, scalable, and high-capacity international connectivity to meet the rapidly growing demands of the digital economy. For more information, please visit: https://www.seren-juno.com/.

SOURCE Ribbon Communications Inc.