Genalyte has developed a multiplex silicon photonic chip diagnostics platform (Maverick<sup>TM</sup>) for rapid detection of up to 32 biological analytes from a drop of sample in just 10 to 20 minutes. The chips are manufactured with waveguides adjacent to ring resonators, and probed with a continuously variable wavelength laser. A shift in the resonant wavelength as mass binds above the ring resonators is measured and is directly proportional to the amount of bound macromolecules. We present here the ability to multiplex the detection of hemorrhagic fever antigens in whole blood, serum, and saliva in a 16 minute assay. Our proof of concept testing of a multiplex antigencapture chip has the ability to detect Zaire Ebola (ZEBOV) recombinant soluble glycoprotein (rsGP), Marburg virus (MARV) Angola recombinant glycoprotein (rGP) and dengue nonstructural protein I (NS1). In parallel, detection of 2 malaria antigens has proven successful, but has yet to be incorporated into multiplex with the others. Each assay performs with sensitivity ranging from 1.6 ng/ml to 39 ng/ml depending on the antigen detected, and with minimal cross-reactivity.
Silicon photonic technology has incredible potential to transform multiplexed bioanalysis on account of the scalability of
device fabrication, which maps favorably to a myriad of medical diagnostic applications. The optical properties of
CMOS-fabricated microring resonators are incredibly responsive to changes in the local dielectric environment
accompanying a biological binding event near the ring surface. Arrays of high-Q microrings were designed to be
individually addressable both in surface derivitization, using well-established microarraying technologies, and in optical
evaluation. The optical response of each ring can be determined in near real time allowing multiple biomolecular
interactions to be simultaneously monitored. We describe a stable and robust measurement platform that allows sensitive
visualization of small molecule surface chemical derivitization as well as monitoring of biological interactions, including
the detection of proteins and nucleic acids. We also present recent results demonstrating multiplexed measurement of
cancer markers. These demonstrations establish a pathway to higher level multiparameter analysis from real-world
patient samples; a development that will enable individualized disease diagnostics and personalized medicine.
We discuss our approach to monolithic integration of Germanium photodectors with CMOS electronics for high speed
optical transceivers. Integration into the CMOS process and optimization of optical coupling into the devices is described,
followed by a discussion on how the devices are deployed in 4×10 Gbs receiver and transmitter subsystems. We
demonstrate -19 dBm optical sensitivity for a bit error rate of 1e-12. An improvement of several dB resulted from
optimizing the transimpedance amplifier relative to a design that was targeted for hybrid integration with flip-chip
photodetectors, in order to take advantage of the drastically reduced capacitance of the integrated photodetectors (below 20
fF). As an example of how the versatility of on-chip waveguides and integrated photodiodes can be used, we further
describe how the Germanium photodetectors are deployed to obtain a fully autonomous Mach-Zehnder interferometer
subsystem with built-in monitoring and control, that can be instantiated as a single cell in an IC design. A fully differential
layout is implemented for optical, electro-optic and electrical components yielding very small mismatch between
components and enabling control of the interferometer with a minimum penalty.
We describe our approach to the monolithic integration of Ge photodetectors in a photonics-enabled CMOS technology.
Ge waveguide photodetectors allow fast and efficient conversion of optical signals in the near infrared (1.55μm) to the
electrical domain thus enabling the fabrication of compact, high speed (10Gbps) receivers.
This paper will briefly outline the technology related to CMOS photonics, and will then discuss systems design aspects
and experimental results from the construction of a 4 wavelength WDM transceiver with each channel running at
10Gbps. Optics including mux/demux, modulation and optical monitoring taps were monolithically integrated into the
0.13 micron CMOS die, alongside the PMD circuitry used for modulator drivers and receiver amplification. A BER of 10<sup>-12</sup>
was achieved on all 4 channels.
Freescale's production 0.13μm SOI process is used to fabricate all required electrical and optical components for 10Gb
interconnect up to 2000m using only 1.7W. The optical transceiver cores are monolithically fabricated with CMOS
circuitry required for bias and control as well as the electrical PHY interface. Optical multiplexing of 4 to 10 channels
allows scaling to 40/100Gb.