The Case for Near-Packaged Optics

Near-Packaged Optics (NPO) is concept that has emerged recently embodying many of the advantages of Co-packaged optics (CPO) but simpler to implement. We think that given that CPO technology is still at its earliest stages, we need a ramp up technology to get us to CPO. NPO uses a high-performance PCB substrate—an interposer—that sits on the host board.  By contrast, in CPO the modules surround the chip on a multi-chip module substrate. While there are other roads to CPO, NPO does seem to have good prospects of being “the one.”  It is close enough to CPO conceptually to provide a clear path to CPO.  At the same time demos and funding from major companies show that real interest is there from the optoelectronics and switching sectors.

Near-Packaged Optics differs from on-board optics (OBO), which is another road to CPO, in that OBO uses a PCB motherboard to do the connection whereas NPO uses a substrate. Unlike the full-blown version of the CPO, NPO needs a DSP integrated with the optical engine.  NPO is a station on the road to CPO and perhaps a better one than OBO.  At present, one can say about on-board optics is that it has not fulfilled its promise from a few years back.  OBO hearkens back to the days of optical flyover technology, NPO looks forward to a new CPO era.  Microsoft has referred to NPO as “CPO Gen-1, the first generation of co-packaged optics,” which makes this point nicely.

  • At OFC 2022, several companies had NPO based switches on display.  They make for an impressive list.  They included Meta (that is Facebook) which showed a next-gen switch based on a 51T ASIC surrounded by NPO ports in a 4RU enclosure. Microsoft has also had kind words to say about NPO.  Having Microsoft as a backer can never be a bad thing, but, then again, Microsoft seems to be behind most efforts to move beyond pluggables.  Still Meta and Microsoft can be viewed as a vote of confidence from the hyperscalers.
  • As we related in a previous blog, OIF has taken upon itself the job of setting “standards” (in the loose sense of the word) for CPO and had its own prototype NPO device on display, with a live ELSFP demo. The lasers were provided by AOI, Cisco, Lumentum, Innolume and O-Net.  (Incidentally, the relatively large number of laser suppliers is an indication, we believe, of the interest that the laser community has in NPO/CPO as a possible future market opportunity.)
  • Yet another company with an interest in NPO or something close is Ayar Labs, which just got $130 million in funding from the likes of Hewlett Packard Enterprise (HPE), NVIDIA GlobalFoundries, Intel Capital, and Lockheed Martin Ventures.
  • Other commercial device firms that showed off their NPO work at OFC 2022 included Luxtera (aka. Cisco) Marvel, Broadcom, and Intel.  Luxtera has been a long-time partner with Meta in the OBO space.  Marvell demonstrated its Teralynx switch platform with NPO electro-optics, in a standard one rack-unit (RU) thirty-two port optical switch.  Broadcom’s switch ASIC demo featured a 25T ASIC with direct drive CPO in half of the ports and copper in balance. Broadcom says it will ship 25T/CPO switches by the end of 2022 and 51T/CPO by the end of 2023.

It is still much too early to say whether Near-Packaged Optics is going anywhere.  We will not feel sure about it one way or another until well into 2023 when the next generation of switches makes its appearance.  Still, NPO seems like a technology worth watching.  It is a way to allow something like CPO to emerge commercially without having to deal with all the implicit complexities of CPO all at once.

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