Zero Change CMOS Microring Modulators at 1550 Nm
Author | : Marc de Cea Falcó |
Publisher | : |
Total Pages | : |
Release | : 2017 |
ISBN-10 | : OCLC:1120646916 |
ISBN-13 | : |
Rating | : 4/5 (16 Downloads) |
Book excerpt: While optical communications are the standard solution for long haul communications, its adoption for short range (i.e, intra- and inter-chip interconnects and metro-area) transmission systems, where a considerable increase in data rates and a decrease in power consumption is to be gained, has been hampered mainly because the high cost associated to the fabrication of discrete optical components. The integration of photonic components in a single substrate, in what is known as silicon photonics, arises as a promising solution to overcome this limitation. Specifically, zero change CMOS silicon photonics, in which photonic components are fabricated in state of the art commercial microelectronic foundries without any change in the fabrication flow, therefore not modifying the transistor yield, enables the monolithic integration of electronics and photonics at a very low cost. Nevertheless, this comes at an expense in the control of the fabrication process and, as such, in the performance of the devices. It is of paramount importance, then, to carefully design, model and optimize these photonic components and test them experimentally. It is the object of this thesis to do so for one of the photonic components necessary for optical communications: modulators. To avoid high optical losses and achieve high optical confinement, the whispering gallery modes of silicon rings (with radii in the order of um) are exploited, and effective modulation is achieved by changing the carrier density in the silicon by means of pn junctions. In this thesis, high speed (25 Gbps) modulation at a working wavelength of 1550 nm is reported for the first time in a zero-change CMOS platform, and it is also demonstrated that this photonics platform can be readily used for low temperature (4 K) applications. A complete model of a silicon microring modulator that includes nonlinear effects (which can have an important detrimental effect in the device performance) is also derived, and from it power handling capabilities of these modulators are determined. By realizing high-speed an efficient optical modulators at the telecommunications wave- length, the potential of these CMOS photonics platform for addressing the future demands in the telecom and datacom systems by the fabrication of high scale electronic-photonic systems has been unveiled.