Source Photonics and Credo transmit single lambda 100G over 20km

20 Sep 2017

Demo at ECOC 2017 promises lower cost 100G transmission and industry accelerating development of 400G links.

Source Photonics: Enabling today's "Cloud-scale" networks.

At the European Conference on Optical Communications (ECOC), held this week in Gothenburg, Sweden, exhibitors Source Photonics and Credo Semiconductor demonstrated the significant achievement of transmitting 100Gbits/sec on a single lambda (wavelength) over 20km of fiber using a compact TOSA and ROSA (transmitter / receiver optical sub-assembly) capable of 53 Gbaud PAM4 operation.

Increasing demand for more bandwidth in Cloud Data Centers is driving the need for more efficient and higher throughput optical transceivers up above the currently deployed 100G wave division multiplexed (4 x 25G parallel channels) technology.

Such next-generation transceivers will need to support higher order modulation techniques such as PAM4 (Pulse Amplitude Modulation) and higher data rate operation at 53 Gbaud, say the partners. Implementations that could be supported with this technology include 400G-DR4/FR4 in addition to 100G-DR/FR/LR.

Low bit-error-rate

The new ECOC demonstration consisted of Source Photonics’ internally packaged TOSA and ROSA sub-assemblies in an optical loopback configuration through 20km of single-mode fiber using a single 100G channel of Credo's low power PAM4 IC technology. The bit-error-rate (BER) after 20km of fiber remained better than the KP4 FEC requirement and was around 5x10^-5.

What this demonstration achieved with one laser and one receiver currently requires four lasers and four receivers -- facilitating not only lower cost future 100G but also accelerating the development of 400G products.

The TOSA is based on Source Photonics' EML laser technology which provides the necessary bandwidth to achieve a TDECQ value below 2.5dB. The room temperature link budget of 10dB provides considerable margin for the most significant link specifications under development in the industry, allowing production margin for performance variations.

The partners commented that these results show that the building blocks necessary to realize 53 Gbaud single lambda operation are available and ready to serve the needs of next generation data center deployments.

“We are continuing to invest in next generation technology, such as Single Lambda 100G, as part of our commitment to providing leading edge solutions for data centers," said Doug Wright, CEO of Source Photonics.

Rajan Pai, vice president of system applications at Credo, added, “The HyperScale Cloud providers have spoken and 100G per lambda solutions are a key connectivity priority. Our SerDes architecture allows us to deliver single-lane 100G performance at the lowest power which will enable the volume deployments of 100G and 400G optical modules."