High Speed, Ultra-broadband and Low Cost Integrated Optical Modulators Based on Graphene

State of the problem or situation that is being addressed: Optical modulators are critical components for both optical communications and on-chip optical interconnects. Semiconductor modulators have been heavily researched over the past few years. However, they have a large device footprint, slow switching time, and narrow operating bandwidth. Recently, as a candidate material for novel optical modulators, graphene has attracted a surge of interest in the academic world. Recently, even though many graphene-based optical modulators have been fabricated in labs and have demonstrated promising potential for various modulator applications, they still face several major challenges that hinder continued development of this class of modulators for potential applications, including low light absorption, low device operation frequency, undesirable modulation depth and compatibility with conventional technology.. General statement of how this problem is being addressed: The proposed project will (1) use a systematic device design that combines both an electromagnetic wave model and circuit impedance model for graphene-based optical modulators, in order to enhance light-graphene interaction and to increase the input electrical signal frequency; (2) improve the device structure by using hexagonal boron nitride insulator which will not only maintain good electron-hole transport of graphene but also prevent doping from device structure; and (3) use of a modified dry-transfer technology for applying CVD-grown graphene which has a strong potential for allowing for low-cost mass production and providing for enhanced CMOS compatibility.. What will be accomplished in Phase I: In this Phase I study, Bioenno Tech LLC will team with Aegis Technology, through the technology transfer from Lawrence Berkeley National Laboratory (LBNL), to develop an innovative class of advanced optical modulators based on graphene. We will further demonstrate an innovative low cost approach (50% potential reduction in costs, compared to a silicon optical modulator) in order to produce optical modulators with higher modulation speed, broader bandwidth, smaller footprint and lower costs over conventionally available optical modulators. The Phase I research will cover device design, processing development, characterization, testing and prototyping, with an aim at identifying the underlying technical issues that control with the fabrication and performance of this novel class of optical modulators. Commercial applications and other benefits: Nowadays, remarkable progress has been made on developing graphene production methods with a number of optoelectronic devices based on graphene that have been recently demonstrated at the lab-scale. However, commercially available device manufacturing methods based on state-of-the-art fabrication processes are still in demand for the mass production of graphene-based optoelectronics. It is critical to bridge both device design and the related fabrication processes. The successful development/fabrication of the high speed, ultra-broadband and low-cost integrated optical modulators, based on graphene, will enable production of critical components for on-chip optical interconnects and high speed data transmission in optical communications. These optical modulators will be able to be mass produced, at low-costs, for various applications including optical signal modulation for high-speed broadband optical communications. Key words: Optical modulator, graphene, low cost, optical communication, circuit impedance, bandwidth, CMOS, high speed. Summary for members of congress: The novel class of optical modulators based on graphene offers several advantages including: (1) high modulation efficiency, (2) fast data transmission capability, (3) ultra-broadband capability, and (4) fast electro-optic conversion for future optical interconnects. These advanced optical modulators offer increased competitiveness in the optical communications market. The development of optical modulators that are small in form factor, light in weight, low in production costs, low in power consumption, and highly integrated at the chip-scale, are essential for advancing optical communications. The proposed devices can be produced at low costs and at large quantities, and can be easily mass produced by the industry. These devices will be compatible with both silicon semiconductor and CMOS technology, and can provide a high degree of flexibility/scalability.