A New Bandwidth Variable Transmitter To Build Future Optical Networks

Traffic demand is seeing a continued growth of about 35 % due to the proliferation of high bandwidth applications, placing greater strain on optical networks. Moreover, traffic requirements are fluid, varying at different times of the day but also due to evolving consumer and business demands.

With this continued growth of network demands and data traffic, there is an urgent need for the development of elastic optical networks, flexible enough to handle a wide range of data types and transmission rates.

The BVT prototype will contribute to fulfilling this need by being able to transmit data in optical transmission networks with a bit rate change in a hitless manner. Assembled by IDEALIST project partners Bell Labs in France, it converts electronic signals to optical signals but with a bandwidth that changes depending on the level of demand. It works without service interruptions, an advantage known as being ‘hitless.’

Changing the signal rate for hitless functioning

Most conventional BVTs function by changing the format of the optical signal, converting between digital and analogue formats. The new BVT created by Nokia Bell Labs changes the signal rate, which is also known as the Baud or modulation rate. This is the number of signal events transmitted per second, with a single second event potentially encoding up to several pieces of information.

The advantage of focusing on the signal rate is that it is easier to implement with electronics and is cost-effective.

This approach incorporates smart processing and makes the transmitter hitless, allowing it to continue functioning regardless of interruption and data loss. This is a particularly innovative development, as transmitters normally have to reconfigure themselves when interrupted, which can take up to several minutes and subsequently causes a halt in traffic.

The prototype is connected to a commercially available optical transport network switch that aggregates many different signals, such as video and audio, and sends it through the transmitter. It works typically at a bit rate of between 10 and 107 Gigabits per second.

For the next step, the BVT will be tested in the field with network operators, integrating it with the management software and systems that control a network from end-to-end.

Building tomorrow’s optical network

Overall, the new device will just be one component in a much larger and more sophisticated flexible optical network being developed by the IDEALIST consortium.

Many of the devices needed to build such a network already exist, including BVTs, but the new prototype is paving the way to ensure that these existing solutions are also fully capable of adapting and innovating to meet the requirements of tomorrow’s optical networks.

The project is committed to researching in detail and providing solutions for the most promising technology to meet the demands of the next generation optical transport network, and to engineer a fully functioning elastic optical network architecture.

This would provide much of the necessary infrastructure for achieving the highly ambitious goals set by the EU’s Digital Market Strategy.