Siemens transmits 'record' 107 Gbit/s on one fiber

21 Dec 2006

Siemens researchers achieve transmission rates of 107 Gbit/s on a single fiber channel using purely electric processing in transmitter and receiver.

In cooperation with Micram, the Fraunhofer Institute for Telecommunications (Heinrich-Hertz-Institut) and Eindhoven Technical University, Siemens has tested what it is calling the network of the future.

The demonstration involved the 100% electrical processing of data rates of 107 Gbit/s and transmission over a 160 km long fiber-optic route in the US - the first time this has ever been done outside the laboratory. Today 107 Gbit is approximately the amount of data that fits on two DVDs.

The record performance was enabled by a newly-developed transmission and receiving system that processes the data purely by electrical means directly before and after its conversion into optical signals. The test was conducted at a long-haul network at one of world's largest optical network operators, in which Siemend has previously deployed a 40 Gbit/s commercial optical network.

Ultra-high bandwidth capacity in core networks will be required to support traffic generated by online games, music, and video downloads. By 2011, legal music downloads alone will account for 36% of the entire music business in Europe according to market research institute Forrester Research.

Network operators are reacting to this development not only by expanding their access networks with broadband technology, but also by adapting the capacities of their optical core networks accordingly.

Recently, Siemens researchers tested data transmission at 107 Gbit/s with 100% electrical processing in the transmitter and receiver, the first time this was achieved outside the laboratory. On the 160 km test route, the scientists improved on the current maximum transmission performance per channel by a factor of 2.5.

The company says that before its latest high rate development for high data rates, signals had to be split into multiple lower data rate signals and later be reconverted from optical to electrical format to avoid data bottlenecks in the downstream electronics (optical multiplexing). This would add cost and reduces system capacity.

But a few months ago, the researchers demonstrated the feasibility of a receiver with 100% electrical processing for optical transmission at a "record" 107 Gbit/s in which the signal from the photo diode is picked up and processed directly by a chip.

Now the next step has been taken and the optical transmitter has been "fully electrified." Siemens has thus developed a system that processes data 100% electrically directly before and after conversion from electrical into optical signals, and vice versa.

"In the spring of 2006, we demonstrated the system with a fully electric receiver," said Rainer Derksen, project coordinator at Siemens Corporate Technology in Munich. "At that time we were still using optical multiplexing in the transmitter. Now we've designed a complete system with 100% electrical processing of the data in both the receiver and the transmitter."

This approach significantly increases the performance of the system. In theory it is possible to process the signals from 100,000 DSL users simultaneously. Derksen expects that the first products based on the prototype will be available on the market within a few years.

100G Ethernet

Such a system would be particularly interesting for the future 100 Gbit/s Ethernet on which telecommunication providers are currently developing. Ethernet - albeit with significantly lower transmission speeds of 1 Gbit/s or less - has long been the data communication standard on corporate and home networks.

Since it transports data in a flexible manner, it is playing an increasingly important role in large carrier networks as well. One of its advantages is that the data is no longer transmitted over switched connections to the end customer, but in packets that can be routed over alternate lines to bypass overloaded or very busy network sections - making the entire network more reliable.

Ethernet's ubiquity has historically followed fast cost degradation as the technology has been massively adopted. Cost for Ethernet ports are expected to outperform their comparable TDM switched variants in cost per bit performance due to this massive adoption and cost decline. Higher flexibility and cost efficiency are the reasons, why 100 Gbit/s Ethernet is the next step in Ethernet transmission technology.