January 2026 Vol. 24 No. 1

Front-line Researchers

• Hirokazu Kameoka, Senior Distinguished Researcher, Communication Science Laboratories, NTT, Inc.

  

  Abstract
  Communication is subject to a variety of constraints arising from physical and psychological conditions and ability as determined by, for example, disabilities, age-related decline, and the challenges of speaking an unfamiliar language. To address these limitations, increasing attention is being directed toward communication-function augmentation technologies, which convert a speaker’s voice in real time to one better suited to the situation, thus removing barriers to effective interaction. Dr. Hirokazu Kameoka, a senior distinguished researcher at NTT Communication Science Laboratories, has long been engaged in research not only on transforming voice quality but also on enabling prosodic modifications such as accent conversion, whisper-to-speech conversion, and electrolaryngeal-to-speech conversion. To meet emerging demands such as creating a “cute” or “tough” voice, he has also begun exploring technologies that enable the subjective impression of speech to be freely manipulated. We asked Dr. Kameoka to look back on his past research achievements, share the current status and concrete outcomes of his latest original projects, and discuss his broader approach to research.

Rising Researchers

• Suguru Endo, Distinguished Researcher, Computer and Data Science Laboratories, NTT, Inc. and Research Center for Theoretical Quantum Information, NTT, Inc.

  

  Abstract
  Quantum computers, currently being researched and developed worldwide, still face several challenges before they can be put to practical use. One of the largest challenges is the frequent occurrence of calculation errors caused by a variety of factors. Overcoming errors caused by the fundamental properties of quantum states is the most important issue for full-scale practical application of quantum computers, and many people worldwide have high hopes for the emergence of large-scale quantum computers with fault tolerance. In this article, we spoke with Suguru Endo, a distinguished researcher at NTT Computer and Data Science Laboratories and a frontrunner who established the world’s first practical method for quantum error mitigation and was selected as one of the “Innovators Under 35 Japan 2021” by MIT Technology Review.

Feature Articles: Toward Commercial Deployment of IOWN APN step3

• Efforts toward Deployment and Dissemination of IOWN APN step3

  

  Abstract
  NTT proposed the IOWN (Innovative Optical and Wireless Network) concept in May 2019 and has been driving the research, development, and practical implementation of the All-Photonics Network (APN). The APN is a novel optical network infrastructure that features ultra-high capacity, ultra-low latency, and ultra-high energy efficiency. In March 2023, the NTT Group started offering APN services, and since then service menus have been expanded. This article introduces initiatives aimed at deploying and promoting “APN step3,” the next evolutionary form of the APN targeted for around 2028.

• Key Technologies Driving APN step3 Deployment

  

  Abstract
  This article introduces three essential technologies for deploying APN step3: Photonic Exchange (Ph-EX), Photonic Gateway (Ph-GW), and Subchannel Circuit eXchange (SCX). Ph-EX enables flexible wavelength configuration and interconnection between different fibers, balancing cost and energy efficiency. Ph-GW supports optical multicast and real-time control for dynamic connectivity. SCX allows subchannel-level bandwidth control and multi-site connections, ensuring deterministic communication.

• Control Technologies Supporting APN step3

  

  Abstract
  This article introduces key control technologies developed by NTT to enable on-demand provisioning and management of optical paths in All-Photonics Network (APN) step3. Specifically, it describes: (i) optical path provisioning technology that enables plug-and-play automatic APN terminal connections; (ii) optical path design technology that enables resource optimization through wavelength conversion; and (iii) control and management technology that enables seamless connectivity between diverse devices and systems with the controller.

• Demonstrating Timely Optical Path Establishment Achieved by APN step3

  

  Abstract
  We are advancing technical studies on All-Photonics Network (APN) step3 to achieve a new connection form that enables users at various locations to connect to the APN only when needed and for the required duration. For the effectiveness and value of this new connection form to appeal to APN users, we have conducted technical demonstrations and use case demonstrations using commercial lines. This article introduces these activities.

Regular Articles

• Preventing Sensitive Data Generation with Positive-unlabeled Diffusion Models

  

  Abstract
  Diffusion models often generate sensitive data that are unwanted by users, mainly because the unlabeled training data frequently contain such sensitive data. However, labeling all sensitive data in the large-scale unlabeled training data is impractical. To solve this, my research colleagues and I propose positive-unlabeled diffusion models, which prevent the generation of sensitive data using a small amount of labeled sensitive data in addition to unlabeled training data. If we have access to clean normal data, then we can prevent the generation of sensitive data since such sensitive data are excluded from the training data. Our key idea is to approximate the training objective function of normal (negative) data using only unlabeled and sensitive (positive) data. Therefore, even without labeled normal data, we can maximize the training objective function for normal data and minimize it for labeled sensitive data, ensuring the generation of only normal data.

Global Standardization Activities

• The Activities of ITU-T Study Group 13 (Future Networks and Emerging Network Technologies)

  

  Abstract
  International Telecommunication Union - Telecommunication Standardization Sector (ITU-T) Study Group 13 (SG13) is working on the concept of future networks. Emerging network technologies, such as networks of low latency and energy efficiency, next-generation mobile networks, and quantum information technologies, are being discussed for their implementation around 2030. This article introduces the future network studies in ITU-T SG13.

External Awards

• External Awards