[1] McGill Univ, Dept Elect & Comp Engn, Photon Syst Grp, Montreal, PQ H3A 2A7, Canada
[2] S China Normal Univ, Sch Informat & Optoelect Sci & Engn, Lab Photon Informat Technol, Guangzhou 510631, Peoples R China
[3] Univ St Andrews, Sch Phys & Astron, Ultrafast Photon Collaborat, St Andrews KY16 9SS, Fife, Scotland
[4] Univ Glasgow, Dept Elect & Elect Engn, Optoelect Res Grp, Glasgow G12 8LT, Lanark, Scotland