Prof Douglas J. Paul > Silicon Photonics

Silicon has long dominated microelectronics and nanoelectronics but due to the indirect bandgap and the lack of any silicon interband laser, many believe silicon is not a material for optics or photonics. There is now significant interest at integrating photonic components onto a silicon chip. This is heavily influenced by the copper interconnects for the input and output being close to the maximum bandwidth and speed. Further speed can only be achieved by moving to optical solutions and using fibre optics to transmit data.


Glasgow has been working on Si Photonics for a number of years and has developed a complete suit of devices which can be integrated together to build complete photonic circuits on top of silicon chips. Components now available include all the passives that Marc Sorel's group has been pioneering (low loss waveguides, couplers, MMIs, slow light devices, high Q cavities (Q > 150,000), delay lines, heater switches and mach-Zehnder phase shifters). My own research group has been strongly involved in looking at active devices including Ge on Si single photon avalanche detectors, quantum confined Stark effect modulators using Ge quantum wells, strain induced long wavelength emission and photodetection and frequency up and down conversion with non-linear Si photonics. We are also involved in trying to make Ge lasers and efficient LEDs for near infrared applications.

Our main focus for the research is now integrated Si photonics for quantum technology and for mid-infrared sensing applications including Ge plasmonics.