The Magneto-Photonic Processing Unit (mPPU) v1.5: A Self-Cooling, Magneto-Volumetric Universal Computer The mPPU is a single-die computing architecture that eliminates the von Neumann bottleneck by collapsing memory, storage, and logic into a single physical element: the magneto-optical pillar. Built on Cerium-Europium-doped Yttrium Iron Garnet (Ce:Eu:YIG) on Silicon-on-Insulator, the architecture processes information using light and magnetism rather than electron flow, achieving 500 GB of unified on-die capacity at 1.6 Petabits per second aggregate internal bandwidth with sub-0.2 nanosecond access latency — requiring no external cooling. Each pillar functions simultaneously as a logic gate (quaternary magnetic state via the Inverse Faraday Effect), a memory cell, and a deep storage element (100-layer Two-Photon Absorption charge storage at 1550 nm). Pillars are distributed in a Fibonacci quasiperiodic lattice that suppresses coherent phonon transport, while Ytterbium-doped Anti-Stokes fluorescence provides active on-die refrigeration, maintaining a steady-state temperature of 31.4°C under full 16-beam parallel load. Version 1.5 introduces the Si₃N₄ photonic crossbar switch matrix, resolving the geometric constraints of ring-resonator coupling at the 0.2 µm pillar pitch through orthogonal TE/TM bus waveguides with sub-wavelength grating plasmonic nano-antennas. The crossbar enables coincident-current write addressing with 4:1 TPA contrast and polarization-routed Faraday readout at ~100 attojoules per read. This release comprises four documents: Specification Sheet — Physical architecture, materials, and performance targets. Fabrication Architecture Report — Complete process flow, engineering mitigations for seven critical failure modes, and a phased prototyping pathway designed for MIT.nano capabilities. PHOTON ISA — A native instruction set in which every instruction maps to a physical event in the crystal: read/write operations, in-situ logic, thermal management, crossbar control, and data movement across a 64-bit Physical Pillar Address space. Compiler Architecture Report — A predictive thermal compiler that treats heat as the fundamental scarce resource, managing sustained training workloads through micro-batch "controlled breathing" cycles at 120 Tbps thermally-managed throughput. The architecture is designed for fabrication using established semiconductor and photonics manufacturing techniques. The core process requires PLD garnet growth, DUV/e-beam Fibonacci lattice patterning, SiO₂ passivation, and oxide-to-oxide wafer bonding of the Si₃N₄ optical interposer. Lead Investigator: Curtis Markley, Sky Bears LLC Research Partners: Oliver (Engineering Architecture), Theodore (Systems Design)
Curtis Markley (Wed,) studied this question.