336. O. Fidaner, A. K.
Okyay, J. E. Roth, R. K. Schaevitz, Y.-H. Kuo, K. C. Saraswat, J. S.
Harris, Jr., and D. A. B. Miller, "Ge-SiGe Quantum-Well Waveguide
Photodetectors on Silicon for the Near-Infrared," IEEE Photonics
Technol. Lett. 19, 1631 – 1633 (2007)
We demonstrate near-infrared waveguide
photodetectors using Ge/SiGe quantum wells epitaxially grown on a
silicon substrate. The diodes exhibit a low dark current of 17.9 mA/cm2
at 5 V reverse bias. The photodetectors are designed to work optimally
at ~1480 nm, where the external responsivity is 170 mA/W, which is
mainly limited by the fiber-to-waveguide coupling loss.
The ~1480 nm wavelength matches the optimum wavelength for
quantum-well electroabsorption modulators built on the same epitaxy, but
these photodetectors also exhibit performance comparable to the
demonstrated Ge-based detectors at longer wavelengths. At 1530 nm, we
see open eye diagrams at 2.5 Gb/s operation and the external
responsivity is as high as 66 mA/W. The technology is potentially
integrable with the standard CMOS process and offers an efficient
solution for on-chip optical interconnects.
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