Dustphotonics Debuts Industry's First 800G Silicon Photonics Chip at ECOC 2023
Last week at the European Conference on Optical Communications (ECOC), we announced a new product that we are excited to share.
This new chip, Carmel-8, is the industry’s first merchant 800Gb/s silicon photonics chip. It is suitable for 800G DR8 and DR8+ transmit applications up to 2km. It is DustPhotonics’ second silicon photonics product, coming on the back of our first Carmel-4 product, which was designed for 400G applications.
Key Features to Highlight
There are several things that are worth pointing out. Not only is this chip the industry’s first merchant 800G silicon photonics chip, but we chose to make it suitable for a wide range of applications. The original Carmel-4 was designed in a 5mm x 5.2mm package. If we had widened the package to simply expand it from 4 to 8 lanes, the simple math says that the chip would have been approximately 10mm wide to enable the 8 lanes.
However, we purposefully improved the layout to keep the chip from becoming too wide and instead chose to design this chip into a 7mm x 7.5mm package. By doing so, we enabled this chip to be used in a wide range of transceiver applications including the narrower (and smaller) QSFP-type form factor.
Chip Variations Displayed at ECOC
We have three versions of this chip. All of them were on display at the conference.
1. Carmel-8 product
This is our standard version of the chip and is suitable for 800G DR8 and DR8+ applications up to 2km. It
consumes <1W total and incorporates on-board lasers using our standard low-loss laser coupling (L3C) process.
2. Carmel-8-IMC product
This is a version of the Carmel-8 product and is specifically designed for immersion cooling. Here, we had a lot of interest at the show as we had an entire Printed Circuit Board (PCB) containing our silicon photonics chip immersed in a special liquid coolant. For fun, we made this appear like an aquarium at the front of our booth (see photo). The coolant we used was one of several off the shelf coolants that is designed for immersion cooling, and is based on a mineral oil that is environmentally friendly and safe for human contact.
Many optical assemblies or transceivers cannot work in when immersed in a liquid, even one that is safe for electronics. This is because these optical assemblies include some amount of “free space” optics. This is basically an open space where light travels in a known path within a transceiver usually towards a lens or away from a lens through air. Unfortunately, even transparent liquids have a different index of refraction than air. This means that immersing these optical assemblies or transceivers into an immersion fluid would create a different optical path than what they are designed for, which could greatly impact performance. However, with the Carmel-8-IMC, we have no free-space optics in the entire transmit chain. That’s because our lasers are butt-coupled to the PIC and the fiber is directly attached to the PIC as well, which enables us to support this immersion cooling application.
3. Carmel-8-Lite
The Carmel-8-Lite is a version of the product that is capable or reduced reach applications. It is cost and power optimized for shorter reaches, including up to 100m on SMF. It can also be used as a non-standard solution over MMF. Today, we are seeing significant shortages in the availability of 100G/channel VCSELs and this product could help alleviate some of those shortages using our 1310nm solution instead. We believe this version of the chip can be used in reduced reach transceiver applications, active optical cables (AOCs), and linear-drive pluggable optics (LPO) applications. The Carmel-8-Lite product consumes less than 0.6W.
Streamlining Transceiver Designs with Carmel-8
The 3 versions of the chip (Carmel-8, Carmel 8-IMC, and Carmel-8-Lite) are all based off the same version of the chip, meaning that transceiver designers can simplify their design efforts by designing a single platform that can be used for all these applications.
This was a very successful show for us and we would like to extend our gratitude to the ECOC 2023 attendees and our dedicated team. Moving forward, we remain committed to driving innovation while valuing simplicity and scalability in our product development journey.
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