A novel optical waveguide H-tree design for synchronous global clock distribution on multichip modules, which has nearly zero clock skew, is developed for a distributed computer system environment. The optical waveguide H-tree design utilizes channel waveguides, curved sections, and directional couplers formed using silica glass and silicon oxynitride channel waveguide technologies. Design calculations are presented comparing these technologies that suggest a hybrid combination having the advantages of each. System performance analysis is carried out for both waveguide technologies and the hybrid combination. These calculations demonstrate the feasibility of this approach and show that the achievable clock speed is limited by the laser diode source and photodiode receiver at each chip module, and not by the optical waveguide distribution network.
Harold W. Carter,
Joseph T. Boyd,
"Synchronous global clock distribution on multichip modules using optical waveguides," Optical Engineering 33(5), (1 May 1994). https://doi.org/10.1117/12.168376