Silicon optical modulators at 1.3- mu m based on free-carrier absorption

Silicon optical waveguide modulators, appropriate for operation in the 1.3-1.55 mu m wavelength region, have been fabricated and their performance characterized at the wavelength of 1.3 mu m. The modulator structures consist of p-i-n diodes integrated with silicon waveguides; device operation is based on free-carrier absorption. Modulation depths of -6.2 dB and response times less than 50 ns have been measured. Experimental results are compared with the p-i-n diode theory. It is argued that the device is suitable for integration with silicon electronics and silicon optoelectronic devices. The response times measured for the current devices may be improved by reducing the transverse dimensions of the p-i-n structure.<>