Subtractive Photonics in Bulk CMOS

Subtractive photonics is presented as a method for implementing photonic waveguides into any bulk CMOS or electronics process. Metal and glass are patterned in the backend layers by foundry to reveal suspended dielectric when metal etched away. This requires simple wet etch provides waveguiding of light up visible regime using broad transparency windows silicon oxides. Mechanical, chemical, considerations discussed, design extensively detailed context 180-nm Example constructed measured, with losses low 4.1 dB/cm multimode waveguide at 1550 nm. In addition, measured range, waveguide-photodiode couplers detailed, electronic–photonic systems demonstrated be unaffected etching.