Mikhail Haurylau

On-Chip Optical Interconnect Roadmap: Challenges and Critical Directions

Intrachip optical interconnects (OIs) have the potential to outperform electrical wires and to ultimately solve the communication bottleneck in high-performance integrated circuits. Performance targets and critical directions for ICs progress are yet to be fully explored. In this paper, the International Technology Roadmap for Semiconductors (ITRS) is used as a reference to explore the requirements that silicon-based ICs must satisfy to successfully outperform copper electrical interconnects (IEs). Considering the state-of-the-art devices, these requirements are extended to specific IC components

Predictions of CMOS compatible on-chip optical interconnect

Interconnect has become a primary bottleneck in integrated circuit design. As CMOS technology is scaled, it will become increasingly difficult for conventional copper interconnect to satisfy the design requirements of delay, power, bandwidth, and noise. On-chip optical interconnect has been considered as a potential substitute for electrical interconnect in the past two decades. In this paper, predictions of the performance of CMOS compatible optical devices are made based on current state-of-art optical technologies. Electrical and optical interconnects are compared for various design criteria based on these predictions. The critical dimensions beyond which optical interconnect becomes advantageous over electrical interconnect are shown to be approximately one tenth of the chip edge length at the 22 nm technology node.

On-chip optical interconnect roadmap: challenges and critical directions

Intrachip optical interconnects can outperform electrical wires but the required parameters for optical components are yet unknown. Here the ITRS is used as a reference point to derive the requirements that optical components must meet.

On-Chip Copper-Based vs. Optical Interconnects: Delay Uncertainty, Latency, Power, and Bandwidth Density Comparative Predictions

As CMOS technology is scaled, it has become increasingly difficult for conventional copper interconnect to satisfy different design requirements. On-chip optical interconnect has been considered as a potential substitute for electrical interconnect. In this paper, predictions of the performance of CMOS compatible optical devices are made based on current state-of-art optical technologies. Based on these predictions, electrical and optical interconnects are compared for delay uncertainty, latency, power, and bandwidth density

Electrical modulation of silicon-based two-dimensional photonic bandgap structures

Electrically tunable photonic band gap (PBG) structures hold the potential to become a versatile and compact backbone for optical signal processing. In this letter we report electrical tuning of silicon-based two-dimensional PBG structures infiltrated with liquid crystals. An improved electrode configuration is used to avoid electric field screening by the conductive silicon walls. Electrical tuning using fields well below 1V∕μm is demonstrated experimentally using both polarized light microscopy and reflectance PBG measurements. The structures can be operated with any electro-optic materials and lead to fast and efficient modulators, routers, and tunable filters.

Electrical and optical on-chip interconnects in scaled microprocessors

The interconnect has become a primary bottleneck in integrated circuit design. As CMOS technology is scaled, it will become increasingly difficult for conventional copper interconnect to satisfy the design requirements of delay, power, bandwidth, and noise. On-chip optical interconnect is therefore being considered as a potential substitute for electrical interconnect. Based on predictions of optical device development, electrical and optical interconnects are compared for various design criteria. The critical dimensions beyond which optical interconnect becomes advantageous over electrical interconnect at the 22 nm technology node are approximately one tenth of the chip edge length.

Electrically Tunable Silicon 2-D Photonic Bandgap Structures

Electrical tuning of high refractive index-contrast photonic bandgap (PBG) structures is required for a majority of PBG applications, particularly for integrated optics. When the host material is a semiconductor with poor electro-optical properties, tuning can be achieved by infiltrating the structure with an active optical material. In this paper we analyze the switching of electro-optic material in such structures, and suggest design rules to help achieve electrical tuning. In particular, a design concept that eliminates the electric field screening effects is proposed. The developed rules and concepts are demonstrated by the electrical tuning of liquid crystals inside two-dimensional porous silicon PBG structures. This approach can be generalized to different combinations of semiconductor PBG structures and active optical materials

Hybrid photonic crystal microcavity switches on SOI

We report the development and characterization of 2-D photonic crystal (PC) microcavity devices on silicon on insulator. The transmission of light through a 2-D PC microcavity near resonance can be switched on and off by modulating the refractive index of the PC. Because silicon has poor electro-optical properties, it is advantageous to insert electro-optic materials inside the air holes. In this work, we report the design, fabrication, and characterization of such hybrid PC microcavity switches using liquid crystals as the electro-optic material. In addition, we demonstrate an electrode geometry that eliminates electric field screening by the more conducting silicon host, and thus enables switching. fabrication.

Electrical tuning of the silicon-based 2-D photonic bandgap structures

Silicon-based 2-D photonic bandgap (PBG) structures have an unmatched potential for integration with well-established microelectronic devices and circuits. They can allow for compact optical devices with enhanced functionality and performance. While a number of passive PBG silicon-based devices have already been demonstrated, electrical tuning of their properties has yet to be implemented. PBG tuning can be achieved by replacing the air inside the device with active optical material, for example liquid crystals (LCs) or an electro-optic polymer. The two main requirements necessary for tuning in PBG structures are (i) the electric field of the control signal should be present inside the active optical material to modify its properties, and (ii) the energy of the optical mode of interest should be distributed inside the active material. While the latter condition can be satisfied by proper optical design, the former requirement is difficult to satisfy due to external electric field screening by the conductive silicon walls. In this work, an analysis of this effect is conducted and guidelines to overcome screening and thus allow for switching are suggested. Further, by using LCs as an active optical material, electric field switching in 2-D silicon-based PBG structures is demonstrated for the first time. Results of this work can lead to the development of silicon-based switches, active routers and filters for future optical interconnects.

Dynamically tunable 1D and 2D photonic bandgap structures for optical interconnect applications

Optical interconnects have begun replacing electrical wires in long distance, backplane applications. As their switching speed and efficiency improves, optical interconnects will penetrate deeper into the device architecture for inter- and intra-chip communications where direct integration with silicon microelectronics is a necessity. Tunable 1D and 2D silicon-based photonic bandgap (PBG) structures are viable building blocks for optical interconnects because they have the capability to redirect light both in- and out-of-plane. In this work, we report on external modulation of the optical properties of 1D and 2D porous silicon PBG structures infiltrated with liquid crystals. This class of eletrooptic modulators offers an inexpensive and versatile way of integrating optical interconnects with standard microelectronic circuits.