Achievement of the world’s fastest data transmission by a “polymer optical modulator

Success in the development of a “polymer optical modulator,” which has been said to be difficult to put into practical application

With the recent dramatic increase in information communication traffic, there is a demand for more sophisticated communication equipment and for a drastic reduction in power consumption. There is also a demand for a cost reduction for high-speed data transmission technology for data centers. An optical modulator made of an organic polymer material, instead of a conventional inorganic material, has been expected as a new technology that would meet these demands.

To address this issue, Professor Yokoyama’s research group developed a polymer that has an excellent electro-optic property and excellent thermal stability jointly with some industries. Moreover, the research group used the polymers to develop waveguide device of an ultra-high-speed optical modulator. As a result, ultra-high-speed optical data transmission that has been hardly enabled by using previous modulators, as well as thermal stabilization and low-voltage driving of the device was successfully achieved for the first time worldwide.

Currently, the group is seeking to apply the polymer optical modulator to silicon optical integration technology. It is expected that this approach will contribute to the improvement of the operating speed of optical communication technologies in various industrial applications, including data centers and IoT, as well as to power saving and cost reduction.


Urgent need to develop optical communication technology capable of accommodating a rapid increase in data transmission volume

A telecom-standard technology known as Ethernet is primarily used for wired computer networks. In Ethernet-compliant networks, an electrical signal is converted to an optical signal at high speed for optical transmission, and transmission speed is increasing year by year. The introduction of 800 Gigabit Ethernet has just been started, and 1.6 Terabit Ethernet, the next-generation standard technology, has begun to be discussed. These situations have created an urgent need to develop a short-distance transmission system that can accommodate a rapid increase in data transmission volume and optical communication equipment that support the system.

In these circumstances, there have recently been growing expectations for an optical modulator made of a polymer with an electro-optic property on a global basis. Compared to the previous optical modulators composed of existing inorganic materials, polymer optical modulator theoretically promises significantly higher speed potential, further drawing attention in terms of power consumption and manufacturing cost as well. For this reason, ultra-high-speed optical data transmission with a polymer optical modulator has been reported worldwide heretofore; however, there have been challenges to overcome in order to put it into practical application.

The world’s first achievement of ultra-high speed, power saving and cost reduction

It is suggested that the electrooptic polymer theoretically has a responsiveness of 100 GHz or higher. In light of this, Professor Yokoyama’s research group was quick to focus attention on an electro-optic polymer material and modulator. The group has been implementing design and synthesis of a high-performance polymer, solution of issues toward reliability improvement, prototyping of an optical modulator, and a study of performance evaluation. The group fabricated a polymer optical modulator and as a result, successfully accomplished a demonstration of ultra-high-speed optical data transmission for the first time worldwide.

In an optical transmission experiment that used the polymer optical modulator, an optical signal of 112 Gb/s OOK was successfully generated. Moreover, it was confirmed that the operating voltage of the optical modulator was regulated at 1.5 volts.