The Need

Technology is advancing faster than ever, with major demand for instant communication and instant information among other industries. In order to facilitate this ever-growing industry, a technology called waveguides were invented. A waveguide confines the wave to propagate in one dimension, so that under ideal conditions, the wave loses no power while propagating. Due to total reflection at the walls, waves are confined to the interior of a waveguide. The complex nature of wave signals, and the countless technologies that often blend together multiple signals, makes it difficult to integrate the technologies. For example, the current state of the art waveguide modulators do not allow for microwave and optical waveguide crossings. The waveguide crossings are required for packaging the modulator with high-frequency co-axial connectors and with standard telecommunications wavelength optical fiber. There are several solutions to this problem but currently none of them produce efficient coupling, making them unable to be inserted into larger systems.

The Technology

Researchers at The Ohio State University have created a waveguide where the optical mode resides primarily in a lithium niobate rib waveguide, and the microwave mode resides primarily in the silicon substrate. Tuning of the layer thicknesses in the ion-sliced lithium niobate, silicon dioxide, and silicon substrate allow the microwave and optical group velocities to be designed with more flexibility. Consequently, velocity matching can be engineered more easily without reducing the electro-optical overlap. Optical waveguides can be etched with smooth sidewalls, allowing for minimal optical propagation losses and an efficient coupling.

Commercial Applications

• Communications
• Navigation Technologies
• Power Industries

Benfits/Advantages

• Efficiency
• Less electro-optical overlap

Research Interests

Ronald Reano is a Professor at Ohio State in the Electrical & Computer Engineering Department. He received his Ph.D from the University of Michigan. His research interests are chip-scale integrated optics and photonics, waveguide nonlinear optics
devices, and planar light-wave circuit technologies for innovation in sensors, communications systems, and computing.