$40M Series A Fuels Quintessent as It Samples Breakthrough Light Source Technology
Quintessent is a startup founded in 2019, spun out of Professor John Bowers' photonics research laboratory at the University of California, Santa Barbara (UCSB). The company recently announced the completion of a $40 million Series A funding round, following its $11.5 million seed round in 2024. At the same time, the company has begun sampling its novel light source, which is designed for optical interconnect applications and aims to provide an alternative to the currently supply-constrained indium phosphide (InP) devices.
The series A round was led by Cycle Capital, along with new investors Goldman Sachs XIG-Industry Ventures, Hina Liberty Capital, Susquehanna International Group, InterVest, Safar Partners, and Ciena. Existing investors including Foothill Ventures, M Ventures, Osage University Partners, and Sierra Ventures also participated.
Quintessent has begun sampling its GaAs quantum dot-based laser emitter for high-speed optical interconnects, offering an alternative to multiple InP sources currently in short supply.
InP laser shortage
Quintessent’s approach uses a frequency comb laser based on a single-chip, quantum-dot emitter, fabricated on gallium arsenide (GaAs) material.
“The market has converged on wide-and-parallel dense wavelength division multiplexing (DWDM) architectures as a leading solution for optical scale-up networks, requiring many orders of magnitude more laser sources to interconnect future AI clusters,” explains the startup.
“At the same time, the massive AI infrastructure buildout has collided with a worldwide shortage of InP lasers; a light source that almost all of today’s optical interconnects universally depend on.”
Quintessent believes that its approach solves both problems, producing eight wavelengths of light from a single laser source using single bias control while taking advantage of the much wider availability of GaAs wafer fabrication capacity and that material’s compatibility with standard silicon photonics.
“The result is a laser architecture designed to reduce power consumption, simplify manufacturing, improve reliability through fewer components, and enable optical connectivity that scales for AI datacenters,” states the firm, with CEO Alan Liu adding:
“For the past several years, we have focused on building technologies designed to make optical connectivity fundamentally simpler to deploy and scale. With today’s news, Quintessent is starting its transition from tech development to a product-focused company. We plan to use our investment to accelerate that transition and meet customer demand.”
Relentless iteration
By reducing the number of individual lasers required, and eliminating certain supporting components, the novel architecture is said to deliver a step-change reduction in the cost of DWDM wavelengths, and up to a 40 per cent reduction in data movement power compared with conventional “narrow-and-fast” architectures.
The investment will be used to further develop the comb laser into a mature platform, through sampling and reliability testing before production is ramped up. The comb laser is currently sampling as an evaluation kit. Quintessent is also looking to develop other key optical components including semiconductor optical amplifiers (SOAs).
Liu, who completed his PhD under Bowers before co-founding the company with his supervisor, added in a LinkedIn post announcing the funding:
“The past 24 months tested our team in more ways than I could have imagined. We made technical and product decisions that were harder in the short term, because we believed they’d compound at scale and over time.
“That came with long stretches of uncertainty where nothing seemed to work as intended and every wafer run uncovered more questions than answers.
“This team gritted through it all with relentless iteration. We pushed through each setback and learned from each failure to chip away at the problem. It took some time to tune the engine, but now it feels like we are firing on all cylinders.”
Source: optics.org
