W. M. J. Green

A 25 Gbps silicon microring modulator based on an interleaved junction.

A silicon microring modulator utilizing an interleaved p-n junction phase shifter with a V(π)L of 0.76 V-cm and a minimum off-resonance insertion loss of less than 0.2 dB is demonstrated. The modulator operates at 25 Gbps at a drive voltage of 1.6 V and 2-3 dB excess optical insertion loss, conditions which correspond to a power consumption of 471 fJ/bit. Eye diagrams are characterized at up to 40 Gbps, and transmission is demonstrated across more than 10 km of single-mode fiber with minimal signal degradation.

Silicon-based heterogeneous photonic integrated circuits for the mid-infrared

In this paper we present our recent work on mid-infrared photonic integrated circuits for spectroscopic sensing applications. We discuss the use of silicon-based photonic integrated circuits for this purpose and detail how a variety of optical functions in the mid-infrared besides passive waveguiding and filtering can be realized, either relying on nonlinear optics or on the integration of other materials such as GaSb-based compound semiconductors, GeSn epitaxy and PbS colloidal nanoparticles.

Silicon Photonic Switches Hybrid-Integrated With CMOS Drivers

This paper describes the design and measured performance of three different silicon photonic switches: a 2×2 switch, a 1×2 switch, and a 4×4 switch. All of the devices have been hybrid integrated with a corresponding custom 90-nm CMOS driver. The 2×2 switch is based on a wavelength-insensitive Mach-Zehnder interferometer (WIMZ) and the 1×2 is based on a two-ring resonator. The power dissipation of the 2×2 WIMZ switch was 2 mW from a 1.0-V supply, with measured transition time of 3.9 ns. The 4×4 switch, composed of six 2×2 Mach-Zehnder interferometer (MZI) switches was demonstrated to route 3×40 Gb/s WDM data with BER <; 10-12, with less than -10-dB crosstalk and 7-dB loss.

Demonstration of a Digital CMOS Driver Codesigned and Integrated With a Broadband Silicon Photonic Switch

A custom 90-nm bulk digital CMOS switch driver is codesigned and integrated with a silicon photonic switch. A photonic device model is created within the electronic design environment, facilitating driver optimization and performance evaluation prior to fabrication. The fabricated drivers implemented in two variations produce transition times as low as 50 ps and generate open eye diagrams using supply voltages ranging from 0.8 to 5 V. The driver is hybrid integrated with a broadband low-power silicon photonic 2 × 2 switch, based on a modified Mach-Zehnder interferometer. The switch has demonstrated operation over 100 nm of spectral bandwidth with less than -17-dB crosstalk, greater than 25 °C tolerance to temperature variations, and compatibility with 1-V driving signals. The integration demonstrates the interoperability of the switch and driver, which together achieve transition times below 4 ns and average power consumption of 2 mW. Finally, throughput bandwidth of 160 Gb/s is demonstrated for all switch configurations via eye diagrams and bit error rate curves.

Comparison of ring resonator and Mach-Zehnder photonic switches integrated with digital CMOS drivers

We report a low-power silicon photonic ring-resonator switch integrated with a CMOS driver that achieves sub 3.5-ns transition times, below -20-dB crosstalk, and ~1-mW combined switch and driver power consumption. Results are compared to non-resonant Mach-Zehnder based switches.

Digital noise-tolerant silicon nanophotonic switch

Error-free switching performance of a digital electro-optic silicon switch based on multi-stage Mach-Zehnder lattice is demonstrated. Robust crosstalk levels of lower than -15dB are obtained for drive-voltage noise levels exceeding 300mV while maintaining error-free operation.

Nonlinear optical interactions in silicon waveguides

Abstract The strong nonlinear response of silicon photonic nanowire waveguides allows for the integration of nonlinear optical functions on a chip. However, the detrimental nonlinear optical absorption in silicon at telecom wavelengths limits the efficiency of many such experiments. In this review, several approaches are proposed and demonstrated to overcome this fundamental issue. By using the proposed methods, we demonstrate amongst others supercontinuum generation, frequency comb generation, a parametric optical amplifier, and a parametric optical oscillator.

Increasing bandwidth density in future optical interconnects

Future challenges to bandwidth scaling within computing systems are considered, including the current unsustainable increase in the number of fibers per system. Several approaches to increase the bandwidth per fiber in future systems are outlined.

High-speed and low-power microring modulators for silicon photonics

Microring-based silicon electro-optic modulators allow high-speed and low-power devices to be fabricated in small footprints. A 30 Gbps reverse-biased microring modulator, and an 8 Gbps forward-biased microring modulator with hybrid-integrated preemphasis driver, are presented.

Silicon integrated nanophotonics for on-chip optical interconnects

As multi-core microprocessor architectures continue to evolve as a promising platform for high-performance computing, an additional set of challenges emerges for the global interconnects between distant cores. In particular, the limited throughput and large power consumption of electrical copper interconnects are becoming dominant factors limiting the continued scaling of processor performance. One promising solution is to complement conventional global interconnects with a CMOS-compatible intra-chip optical network, based on silicon-on-insulator (SOI) photonic integrated circuits. We will review recent results on silicon nanophotonic circuits based on SOI photonic wires and photonic crystals. Silicon nanophotonic devices have immense capacity for low-loss, high-bandwidth data transmission, and can confine light within sub-micron dimensions, enabling the design of ultra-compact optical devices for all necessary functions within such optical networks. While the bandwidth and power consumption advantages of SOI optical interconnects are potentially immense, ensuring the performance of chip-scale networks places stringent requirements upon the control of the manufacturing process, and its influence upon the operation of individual optical components. We will present recent work on the design, fabrication, and demonstration of various passive and electrooptic devices required for high speed optical interconnect applications, including high-order WDM optical filters, modulators, and switches.