NTT Investigates Holey Fiber

TOKYO -- Nippon Telegraph and Telephone Corporation (NTT -- Chiyoda-ku, Tokyo, President: Norio Wada) has made giant leaps in research into the application of a new optical fiber that possesses optical properties unattainable with conventional fiber. The fiber is attracting attention as the next generation of transmission medium and photonic device.

The new optical fiber is called "Holey fiber" (*1). While conventional optical fiber is composed of a core surrounded by a cladding, the core of holey fiber contains air holes arranged like a crystal lattice (Figure). Through design of the size, number, separation, and arrangement of the holes, holey fiber has achieved many optical characteristics impossible with conventional fiber such as single-mode in an extremely wide range of wavelengths, a dramatic reduction in bending loss, and high polarization maintenance. The pronounced reduction in bending loss has made holey fiber markedly easier to handle, unlike its conventional counterpart, which does not transmit light through when bent. This means that no special cable-laying procedure is required and that laying and installation is more flexible.

Now that the broadband era is well and truly upon us, and at a time of rapid growth in fiber optic services exemplified by B FLETS, holey fiber, the result of pioneering research and development by NTT, is expected to contribute to the provision of a fast, low-cost fiber optic service to customers.

NTT will continue to conduct research into the feasibility of photonic crystal optical fiber as a future transmission medium in the form of discovering transmission characteristics at wide wavelengths and investigating how the performance of such transmission can be improved, as well as establishing testing, connection, and cabling technologies. We are also continuing to investigate alternative structures for bend-resistant optical fiber and will continue research and development with the aim of applying this technology as soon as possible.

NTT Group