The initial Series A was announced at $11 million in 2018 and led by Matrix Partners and Spark Capital. (see MIT spin-off raises funds for optical processor). Now GV, formerly Google Ventures) has added joined in and the Series A has been raised to $33 million.
The company employs 23 engineers and scientists and taped out its test chip in May 2018 followed by a chip with over one billion transistors at the end of 2018. It could well be this milestone that persuaded GV to join in the project.
Lightmatter is seeking to replace the 2D arrays of multiply-accumulate units used in conventional neural network hardware with an optical counterpart: the programmable Mach-Zehnder interferometer. The use of the mixing of optical beams to perform matrix multiplication consumes much less power than complex electronic circuits and should therefore allow greater scaling and miniaturization, Lightmatter said.
It should be noted that a similar startup was spun off from MIT at about the same time as Lightmatter. Lightelligence Inc. (Boston, MA) also seeks to commercialize optical processing as an approach to artificial intelligence but as received backing from Chinese internet services company Baidu.