FAQ: Expanding on POET Starlight and the Partnership with Celestial AI

April 25th, 2023

POET Technologies announced on April 25 a new product for the artificial intelligence hardware (AI) market. POET Starlight is a packaged light source solution for AI applications. To build it, POET has entered into a co-development agreement with Celestial AI, an AI chip company. POET Starlight products are based on the POET LightBar™, which earned industry acclaim when it was demonstrated at the Optical Fiber Conference (OFC) in March 2023.  

POET Starlight solidifies the companys status as an AI hardware supplier. Here is an FAQ to explain the agreement with Celestial AI and POETs AI solutions in more detail.


1. What does POET Starlight do?

POET Starlight is the source for multiple colors of light to power up external silicon photonics modulators and manage the data flow among chips in an AI system. Using light for data transmission is faster and consumes lower power than other materials and, importantly, light generates less heat — by a factor of 10 times than electrons that go through copper. The light is generated by lasers that are passively flip-chipped onto the POET Optical Interposerplatform.

By using light, POET not only helps AI hardware developers create a more efficient product, it also gives them an assurance that it will have access to light source designs that have the scalability they require over time. POET Starlight’s current design can accommodate the high-volume manufacturing targets of Celestial AI and others engaged in the development of optical interconnect technology platforms. Designs under development by POET promise to extend that efficiency of power and cost into future generations of AI hardware.

POET’s light engines feature remote light sources for co-packaged optics and chip-to-chip communications. Their attributes include: uncooled, passively attached DFB Lasers; 4-channel and 8-channel configurations; excellent side-mode suppression ratio (SMSR) and power uniformity; the flexibility to integrate splitters, combiners, and other components that can be customized; and built-in SSC for lasers.

POET is also a member of the CW-WDM MSA (Continuous-Wave Wavelength Division Multiplexing Multi-Source Agreement), which is standardizing wavelength and power specifications of lasers that are used in AI. POET is developing products that adhere to CW-WDM MSA specifications.


2. What is the difference between POET Starlight and the POET LightBar that it's built on?

POET LightBar is an optical engine with high-power continuous wave (CW) lasers passively attached to the optical interposer. Customers can use the LightBar in their solutions but would typically require some custom engineering work to couple light from the LightBar to their photonics. POET Starlight is a complete packaged light source that incorporates the LightBar along with other passive optical components and is connectorized on the electrical and optical ends. AI customers can use the Starlight product directly on their boards without requiring any additional optical alignments.


3. Why does the AI industry need photonics?

Many observers believe that communication bandwidth is the biggest obstacle facing the AI industry as it attempts to meet large-scale demand with more robust applications. The reliance on antiquated computer hardware architectures is limiting the growth of AI. Bottlenecks in data flow are an impediment for AI software developers who are building more sophisticated applications that require greater bandwidth in order to be deployed to a massive volume of users. Eliminating those bottlenecks is critical. Hardware solutions that use photonics to speed light through fiber-optic cables is essential, but doesnt address the barriers in fundamental computer architecture which are an impediment to the continuing rapid expansion of AI.

At a base first, fiber-optics can deliver data between servers that are located far apart from each other. Fiber-optic communication offers several advantages over traditional copper wires, including faster data transmission speeds and better resistance to interference from electromagnetic radiation. This feature is particularly important for AI programs like ChatGPT, which require massive amounts of data to be transmitted and processed quickly and efficiently from servers to end users.
The next level for photonics to penetrate AI is in the basic computing architecture, by either performing complex computations using light or using light to transmit data among closely coupled processors in an AI system.  Celestial AI says its mission is to fundamentally transform computing efficiency with its Photonic Fabric™ technology platform that uses light for data movement both within chip and between chips. POETs light engines provide Celestial AI with precision optical power sources in a highly integrated form factor that delivers the power and performance needed by the AI industry.


4. What is the market potential for POET Starlight and other products built with POET’s LightBars?

The chip market is projected by Allied Market research to surpass $263 billion by 2031. Thats just for the hardware solutions. The overall AI market is forecast to reach into the trillions of dollars by that same time. As the market grows, so does POETs potential to gain an increased share of it. Celestial AI has already placed an initial order for POET Starlight units as part of the scope-of-work agreement signed in April 2023.

External light sources for AI have been one of the key verticals for POET for years. The market is opening for these light sources and the light engines built from them. POET Starlight is only one light engine that uses the POET LightBar. More products are expected to emerge as companies focus on AI and turn their attention to POET. The companys ability to integrate active components like lasers and certain other passive optical and electrical components into the optical interposer to provide a complete light source solution is an increasingly attractive option.

In a Zacks research report published on April 10, an analyst said POETs relationship with Celestial AI “could represent $800 million in potential revenues by itself. We believe most if not everything Celestial is planning to sell contains POET.

In March, POET demonstrated its O-Band LightBar with high-power CW lasers for co-packaged optics and AI GPUs. The LightBar can be integrated on a host board and connected to chips and ASICs with built-in silicon photonics. The demonstration was met with much praise by the industry and has resulted in numerous conversations with existing and potential customers.


5. What is the difference between the POET Starlight C-Band and O-Band products?

Both are light engines but they operate at different wavelengths and each one fits the requirement needs of different customers. The O-Band and C-Band are not specific to any one market. They represent the wavelength bands where fiber loss is minimum. Both bands are used in AI, datacom, and sensing applications. Why one customer would use C-Band over O-Band, or vice-versa, depends on its reach requirements, the customer’s technology, and other variables.

POET offers both C-Band and O-Band light engines.


6. Does POET Starlight result in cost savings over other solutions?

Yes. While pricing of POET Starlight has yet to be determined, POET knows that it will offer Celestial AI savings of up to 75% over what’s currently available from other light source suppliers. POET can provide that incredible cost reduction because of the elegance of the POET Optical Interposer, which has a drastically lower bill of materials and reduced capital expense requirements.

POETs Starlight C-Band and O-Band LightBar products incorporate monolithically integrated passive components like multiplexers, demultiplexers, splitters, combiners, and waveguides. Known-good high-power CW lasers and monitor photodiodes are flip-chipped and passively attached to the optical interposer platform. That wafer-scale design eliminates the need for laser arrays, which can be cost prohibitive for high-volume applications.

POET achieves its low-cost solution through the use of features and benefits of the POET Optical Interposer and the semiconductorizationof photonics fabrication processes.


7. Is POET now also an AI company?

Yes, absolutely. While the POET Optical Interposer was invented to help datacenter and telecom companies overcome the limitations of legacy solutions, it turns out that the company also happens to be in the right place at the right time with the right solution for AI.

The hybrid-integration platform technology is suited for AI developers — as it is for datacenter suppliers and telecoms, among others — and POET's light engines put it firmly in the AI ecosystem. 


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