Keysight pushes to 110GHz for terabit high speed serial and optical designs
The Infiniium UXR family of scopes is aimed at the latest high-speed serial such as DDR, USB and PCIe and optical designs as well as PAM4, 5G, radar and satellite communications.
“When we started this programme and looked at what the customer needs would be in the future we made a conscious decision to develop an entirely new technology set rather than adapt existing technology, that always has tradeoffs,” said Dave Cipriani, Vice President for the Digital and Photonics Centre of Excellence at Keysight.
“It’s a completely new chipset on the next generation of the process, HB2D. This fourth generation 300GHz InP enables direct capture of the 110GHz without interleaving and we developed several chips in the front end module: a signal conditioning amplifier, the pre-amp in the HB2D InP process that goes into a 256Ga/S sampler and then into a SiGe process with lower samplers that we can get commercially.”
The 10bit differential A/D converter operates at 64Gsample/s and is interleaved across four chips so provide the total sampling of 256Ga/S, and in the high end 110GHz system there is one acquisition card per channel.
“This means we are sampling 10Tbit/s – we take 34 measurements in the time it takes light to travel 1cm,” he said. “To process all of this data we invented a new processor in 28nnm CMOS – do some of the correction ion phase and magnitude and interleaving correction using proprietary filters. We’ve also added hardware acceleration in key areas so we have 100K waveform/s in the plotter, up from 3K in software. Another area is the display and measurements for real time eye measurements – 1m /s – this is a big benefit to debugging serial buses.”
The chassis handles four channels, but units can be combined in a master-slave architecture for wider data capture. “We put four channels in the box as any coherent applications with an IQ pair need tight correlation,” said Cipriani. “So we achieve 25fs jitter on a channel and, just as importantly, the jitter between 2 channels is 35fs.” The record length is 2Gbytes/channel.
“We have a way to connect multiple scopes together with good correlation,” he said. “It will follow the current Z series in a master slave where one of the precision clocks fans out to the different systems and we have gone up to 20 channels with that but we haven’t done the performance monitoring on that yet for the UXR.”
Across the 13GHz to 110GHz range there are really different application needs, he says, so the 80 to 110GHz systems have a proprietary 1mm connector on the front. “We felt we needed to come up with more robust connectors,” he said,
In the 40-70GHz mid range he sees a lot of opportunity in 5G I/O serial buses in the data centre and the fifth generation of PCI-X. “There’s a centre of need around 50GHz,” he said.
In the 13 to 33GHz range the issue is more about cost, so this has a 128GSample/s data rate by using two of the acquisition cards to reduce the overall system cost.
“Under 33GHz we just felt was 128Ga/s is plenty for a 33GHz system with 4x oversampling and allows 2 channels per acquisition board and that allows us to reduce the price,” he said.
“The early units that we sold were all in the high end – we work with the defining customers and give them earlier access and it is often best to do that for customers at the cutting edge and they can use early versions of the products,” he said. “Researchers were the early customers and they are writing papers where we have enabled them to make measurements on terabit data transmission around the world.”
Keysight has also used the InP front end chips, built at the Keysight plant in Santa Rosa, california, in an Optical Modulation Analyzer (OMA) for complex optical data transmission and terabit measurements and a 120 GSa/s arbitrary waveform generator for generating challenging formats such as 64 GBaud 64QAM (quadrature amplitude modulation) and other wideband modulation schemes.
Related stories:
- KEYSIGHT TEAMS WITH NTT DOCOMO ON 5G NETWORK EMULATION
- KEYSIGHT BUYS THALES CALIBRATION DIVISION IN AUSTRALIA
- 64G PAM4 SIGNAL QUALITY ANALYZER TO CHARACTERIZE 400G/800G OPTICAL MODULES
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