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Chang-Hasnain

Connie Chang-Hasnain, Palo Alto, CA US

Patent application numberDescriptionPublished
20090074019OPTICAL INJECTION LOCKING OF VCSELS FOR WAVELENGTH DIVISION MULTIPLEXED PASSIVE OPTICAL NETWORKS (WDM-PONS) - Low cost implementation of broadband upstream transmission for local and access network applications is made possible through the use of modulated downstream signals in a wavelength division multiplexed (WDM) passive optical network (PON) to injection-lock vertical-cavity surface-emitting lasers (VCSELs) for operation as stable, uncooled, and directly-modulated upstream transmitters. By way of example and not limitation, an optical network unit comprises: downstream input, photoreceiver, tunable laser, upstream output, and means for directionally coupling the downstream input into the tunable laser for modulating the output wavelength which is coupled to the upstream output.03-19-2009
20110146771NANONEEDLE PLASMONIC PHOTODETECTORS AND SOLAR CELLS - The present disclosure provides a catalyst-free growth mode of defect-free Gallium Arsenide (GaAs)-based nanoneedles on silicon (Si) substrates with a complementary metal-oxide-semiconductor (CMOS)-compatible growth temperature of around 400° C. Each nanoneedle has a sharp 2 to 5 nanometer (nm) tip, a 600 nm wide base and a 4 micrometer (μm) length. Thus, the disclosed nanoneedles are substantially hexagonal needle-like crystal structures that assume a 6° to 9° tapered shape. The 600 nm wide base allows the typical micro-fabrication processes, such as optical lithography, to be applied. Therefore, nanoneedles are an ideal platform for the integration of optoelectronic devices on Si substrates. A nanoneedle avalanche photodiode (APD) grown on silicon is presented in this disclosure as a device application example. The APD attains a high current gain of 265 with only 8V bias.06-23-2011
20110150502HIGH-SPEED OPTICAL TRANSMITTERS USING CASCADED OPTICALLY INJECTION-LOCKED LASERS - Apparatus and method for increasing optical transmission bandwidth in response to chaining, in cascade, one or more slave lasers onto a master laser. Each laser is configured for optical injection locking (OIL) and each slave laser is locked onto the master laser. The first and each subsequent slave laser are detuned to tailor frequency characteristics of apparatus output. The transmitter can be scaled up by cascading additional injection-locked lasers together. The invention supports multiple compatible modulation formats, such as amplitude modulation (AM), phase modulation (PM), and frequency modulation (FM), for tailoring the output to the application of interest, while any type of laser can be used for the master and slave lasers.06-23-2011

Patent applications by Connie Chang-Hasnain, Palo Alto, CA US

Connie J. Chang-Hasnain, Palo Alto, CA US

Patent application numberDescriptionPublished
20100316079SUB-WAVELENGTH GRATING INTEGRATED VCSEL - A vertical cavity surface emitting laser (VCSEL) is described using a sub-wavelength grating (SWG) structure that has a very broad reflection spectrum and very high reflectivity. The grating comprises segments of high and low refractive index materials with an index differential between the high and low index materials. By way of example, a SWG reflective structure is disposed over a low index cavity region and above another reflective layer (either SWG or DBR). In one embodiment, the SWG structure is movable, such as according to MEMS techniques, in relation to the opposing reflector to provide wavelength selective tuning. The SWG-VCSEL design is scalable to form the optical cavities for a range of SWG-VCSELs at different wavelengths, and wavelength ranges.12-16-2010
20100316083SUB-WAVELENGTH GRATING INTEGRATED VCSEL - A vertical cavity surface emitting laser (VCSEL) is described using a sub-wavelength grating (SWG) structure that has a very broad reflection spectrum and very high reflectivity. The grating comprises segments of high and low refractive index materials with an index differential between the high and low index materials. By way of example, a SWG reflective structure is disposed over a low index cavity region and above another reflective layer (either SWG or DBR). In one embodiment, the SWG structure is movable, such as according to MEMS techniques, in relation to the opposing reflector to provide wavelength selective tuning. The SWG-VCSEL design is scalable to form the optical cavities for a range of SWG-VCSELs at different wavelengths, and wavelength ranges.12-16-2010

Patent applications by Connie J. Chang-Hasnain, Palo Alto, CA US

Constance Chang-Hasnain, Palo Alto, CA US

Patent application numberDescriptionPublished
20090269244Detection of biochemical interactions on a biosensor using tunable filters and tunable lasers - An apparatus and method for detection of peak wavelength values of colorimetric resonant optical biosensors using tunable filters and tunable lasers is provided. Biomolecular interactions may be detected on a biosensor by directing collimated white light towards a surface of the biosensor. Molecular binding on the surface of the biosensor is indicated in a shift in the peak wavelength value of the reflected or transmitted light from the biosensor, while an increase in the wavelength corresponds to an increase in molecular absorption. A tunable laser light source may generate the collimated white light and a tunable filter may receive the reflected or transmitted light and pass the light to a photodiode sensor. The photodiode sensor then quantifies an amount of the light reflected or transmitted through the tunable filter as a function of the tuning voltage of the tunable filter.10-29-2009