333. J. E. Roth, O. Fidaner, R. K.
Schaevitz, Y. -H. Kuo, T. I. Kamins, J. S. Harris, and D. A. B. Miller,
"Optical modulator on silicon employing germanium quantum wells," Opt.
Express 15, 5851-5859 (2007)
demonstrate an electroabsorption modulator on a silicon substrate based
on the quantum confined Stark effect in strained germanium quantum wells
with silicon-germanium barriers. The peak contrast ratio is 7.3 dB at
1457 nm for a 10 V swing, and exceeds 3 dB from 1441 nm to 1461 nm. The
novel side-entry structure employs an asymmetric Fabry-Perot resonator
at oblique incidence. Unlike waveguide modulators, the design is
insensitive to positional misalignment, maintaining > 3 dB contrast
while translating the incident beam 87
and 460 mm
in orthogonal directions. Since the optical ports are on the substrate
edges, the wafer top and bottom are left free for electrical
interconnections and thermal management.