[1] Stanford Univ, Dept Appl Phys, Stanford, CA 94305 USA
[2] Australian Natl Univ, Laser Phys Ctr, Ctr Ultrahigh Bandwidth Devices Opt Syst, Canberra, ACT 0200, Australia
[3] Univ Sydney, Sch Phys, Ctr Ultrahigh Bandwidth Devices Opt Syst, Sydney, NSW 2006, Australia
[4] Univ Calif Santa Barbara, Dept Elect & Comp Engn, Santa Barbara, CA 93106 USA
[5] Stanford Univ, EL Ginzton Lab, Stanford, CA 94305 USA