Silicon-photonic MAC tile
Matrix-multiply done in light at 1550 nm — sub-picojoule per MAC. The same descent, one paradigm out.
The frontier exemplar, and the point where the classification flips. On the ring, the compute (the MCU) was settled reuse and the frontier sat in the sensor. Here the compute itself is on the frontier — there is no photonic matrix core to buy off a reel — in the substrate where a multiply-accumulate costs the fewest joules. The passives, the laser, the readout, and the drive electronics around it are still settled reuse. Whether that frontier is worth it depends on the goal.
Exploded
Decompose the product into its stack. Each layer is colour-coded: settled, cyclical, or frontier.
Bill of materials
Every part is a real, sourced component from the open baseline — no invented part numbers.
This is the computer. There is no off-the-shelf photonic matrix core — the mesh topology, the loss budget, and the calibration are the design. The multiply-accumulate primitive realised in the substrate where it costs the least energy.
https://gdsfactory.github.io/gdsfactory/ →Thermal phase shifters burn static power continuously — the scaling constraint. A frontier option: non-volatile phase shifters (phase-change / MEMS / BTO) that hold weights at zero idle power, at the cost of a less-proven device.
Compact slow-light EO modulators (TeMPO-class) cut the area and drive energy of the encoder — co-designed with the CMOS driver below.
https://www.aimphotonics.com/pdk →Mature PDK passive. Reuse as-is.
https://github.com/SiEPIC →Standard, qualified PDK component. Reuse.
https://www.aimphotonics.com/pdk →Telecom-volume commodity. Reuse.
Standard CMOS that refreshes on a node clock — reuse the current generation; the co-design opportunity is the interface, not the process.
Settled PDK passive layer. Reuse.
Where openWafer can help
At a new paradigm the cost-and-differentiation question dominates the whole compute path. The MZI mesh, the phase-shifter technology, and the modulator are the matrix-multiply primitive realised in light, in the substrate where it dissipates the fewest joules per operation; the passives, laser, photodetector, and CMOS drive are settled reuse. This is the case where the frontier is most of the system — a fit when the goal is differentiation or advancing the science, a poor fit when the goal is to ship a known product cheaply. One frontier move that makes photonic compute scale is replacing power-hungry thermo-optic tuning with non-volatile phase shifters that hold weights at zero idle power. Same descent as the ring, one paradigm out: the goal decides whether the frontier is worth it.