400GbE PAM4 BER measurements in one package

Due to the expansion of next-generation 5G mobile communications and Cloud services, data traffic volumes are expected to increase.

To manage this demand, infrastructure operators, such as data centers, are investigating the improvements to speed in PAM4 and multilane communications systems.

Now 400GbE speeds are being deployed using either the 26.5625Gbaud PAM4 x 8 lanes or 53.125- Gbaud PAM4 x 4 lanes methods.

To meet this technical demand, Anritsu has developed the released 64-Gbaud PAM4 PPG with ‘best-in-class’ signal level quality and the 32-Gbaud PAM4 ED with excellent Rx sensitivity performance to support evaluation of equipment and devices for high-speed, large-capacity transmissions.

When using the PAM4 method to encode data as four amplitude levels, the gap between signal levels is one-third compared to the NRZ method, which reduces the unit time per symbol at higher baud rates, emphasising the importance of signal quality in achieving high-speed transmissions.

However, the degraded signal quality caused by crosstalk and noise resulting from use of multiple lanes and high-density circuit design increases the need for evaluation of minimum Rx sensitivity using stress-test signals.

The Signal Quality Analyser-R MP1900A is a leading bit error rate tester for the over 400G market and supports generation of high-speed signals as well as analysis of signal performance.

The new PPG for PAM4 signals up to 64 Gbaud has the world’s best Tr/Tf (20% to 80%) time of 8.5 ps (typ.) and Intrinsic Jitter of 170 fs (typ.).

Moreover, the multichannel function can be expanded up to 4 channels, and the integrated Emphasis function corrects signals degraded by transmission path loss.

The 32-Gbaud PAM4 ED module has a high sensitivity performance of 23 mV (typ.) and supports installation of a clock recovery function required for Rx sensitivity evaluation, as well as PAM4 symbol error measurements.

As a result, the true performance of 400GbE optical modules and devices can now be tested within an adequate margin, satisfying the specifications. This means you can now avoid difficulties in achieving an accurate evaluation due to inadequate signal quality.

Additionally, the multichannel expandability helps cut measurement times using simultaneous measurement of multiple lanes. Moreover, easy combination with jitter and noise addition functions to configure an all-in-one test solution for evaluating Rx sensitivity, helps improve development and testing efficiency.