High finesse silicon Fabry-Perot optical intensity modulators fabricated by merged epitaxial lateral overgrowth (MELO)
Abstract
Prospects for optoelectronics ICs (OEICs) are actually less discouraging for Si than for III-V compounds because, in Si, heterojunctions and alloy compositions are not required. The compatibility with the well developed VLSI technology used for the fabrication of silicon integrated circuits is also an important motivation. The choice of wavelengths for operating Si devices has been focused onto the range from 1.2 to 1.6 $\mu$m since crystalline Si is highly transparent over these interval. These wavelengths are also the working wavelengths for using low loss optical fibers as the communication media. A surface-normal reflection type optical intensity modulator usually consists of two functional components. One is the device which can provide electrical modulation signal into crystal silicon(c-Si), the other is a structure that provides a mechanism to convert the phase modulation (due to electrical signal) into intensity modulation. A PIN diode can be used as a carrier injector for providing electrical tuning signal while the Fabry-Perot cavity with high finesse is suitable for converting the phase difference into intensity changes. A Fabry-Perot cavity using the merged silicon epitaxial lateral overgrowth (MELO) technique, has been fabricated and evaluated. The maximum modulation depth is measured to be 40% under injection current density of 16 A/cm$\sp2$. The current density can be made even lower if the finesse (now is calculated to be 19.26) of the cavity is further increased. The measured value was at least 6.8 but if measured with Fourier transform infrared spectrometers or by using laser as the light source, it may have been larger.
Degree
Ph.D.
Advisors
Neudeck, Purdue University.
Subject Area
Electrical engineering
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