Two-Channel Electronically Tunable Integrated Optical Waveguide Coupler On SOI

Abstract

Integrated electro-optic waveguide coupler is a potential candidate for telecommunication systems which provides a promising platform to realize integrated waveguide devices. High speed active waveguide devices which may include optical switches and modulators have been a challenging subject in modern integrated optics. In an effort to move this important issue along, this work mainly focuses on concepts of improving the self-imaging quality of wave guide coupler in terms of coupling length analysis. Optical waveguide couplers have been comprehensively studied over the years due to its diverse application in the systems of time division multiplexing space division multiplexing and wavelength division multiplexing. Recently the high speed silicon waveguide coupler, one of the key component for integrated Si photonic chip are used to transmit Tb/s data over the communication link and attracted a lot of attention for next generation communication network as well as high performance computing applications. To decrease the coupling length of high speed active waveguide devices, an electronically tunable waveguide coupler based on carrier plasma dispersion effect incorporating silicon on insulator rib waveguide is proposed. Silicon-on-insulator (SOI) optical waveguides have emerged as an attractive class to design advanced low-power, high-speed opto-electronic devices. The design of the wave guide coupler is presented by optimizing the various device parameters, such as waveguide width (w), height (h) and gap (g) between the waveguides to obtain shortest switching length at small power. Design and simulation of such structure is performed with finite difference method. By varying the separation between the wave guides partial image and complete image has been formed at gap 0.05μm and 0.07μm respectively. Coupling lengths for partial image and complete image are reported 7.7μm and 27.48 μm respectively in simulation at 1 volt. Reduction in coupling length of about 4 times and 1.06 times for partial images and complete images respectively are achieved from 0 volt to 1 volt. Thus tuning of waveguide coupler in this way provides a promising approach for enabling high speed sub-micron size active waveguide devices on Si and it can also offer the multi channel waveguide coupler for applications in WDM systems.