Ge/SiGe asymmetric Fabry-Perot quantum well electroabsorption modulators Elizabeth H. Edwards,1,∗ Ross M. Audet,1 Edward T. Fei,1 Stephanie A. Claussen,1 Rebecca K. Schaevitz,2 Emel Tasyurek,1 Yiwen Rong,3 Theodore I. Kamins,1 James S. Harris,1 and David A. B. Miller1 1Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA 2Current address: Corning West Technology Center, Palo Alto, CA 94304, USA 3Current address: Philips LumiLEDs, San Jose, CA 95131, USA ∗[email protected] Abstract: We demonstrate vertical-incidence electroabsorption mod- ulators for free-space optical interconnects. The devices operate via the quantum-confined Stark effect in Ge/SiGe quantum wells grown on silicon substrates by reduced pressure chemical vapor deposition. The strong electroabsorption contrast enables use of a moderate-Q asymmetric Fabry-Perot resonant cavity, formed using a film transfer process, which allows for operation over a wide optical bandwidth without thermal tuning. Extinction ratios of 3.4 dB and 2.5 dB are obtained for 3 V and 1.5 V drive swings, respectively, with insertion loss less than 4.5 dB. For 60 µm diameter devices, large signal modulation is demonstrated at 2 Gbps, and a 3 dB modulation bandwidth of 3.5 GHz is observed. These devices show promise for high-speed, low-energy operation given further miniaturization. © 2012 Optical Society of America OCIS codes: (230.4110) Modulators; (230.4205) Multiple quantum well (MQW) modulators; (200.4650) Optical Interconnects; (250.0250) Optoelectronics. References and links 1. D. A. B. Miller, “Device requirements for optical interconnects to silicon chips,” Proc. IEEE 97, 1166–1185 (2009). 2. G. T. Reed, G. Mashanovich, F. Y. Gardes, and D. J. 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