Patents by Inventor Yu-Hwa Lo
Yu-Hwa Lo has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20090128922Abstract: The present invention in various embodiments relates to a variety of different types of fluidic adaptive lens systems, pumping systems for implementation in such lens systems, other systems employing such lens systems, and related methods of fabrication. In at least some embodiments, the present invention relates to a lens system that includes a reservoir having at least one flexible wall, a first actuator coupled in relation to the reservoir, and a terminal at which is located at least one of an integrated fluidic lens and a port configured to be coupled to an external fluidic lens. The terminal is coupled to at least one of the reservoir and the actuator, and at least one of the actuator and a first pumping system including the actuator is capable of causing fluid to be moved at least one of from the reservoir toward the terminal, and from the terminal toward the reservoir.Type: ApplicationFiled: November 4, 2005Publication date: May 21, 2009Inventors: Nicole B. Justis, De-Ying Zhang, Yu-Hwa Lo
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Publication number: 20090027666Abstract: A flow cytometry system and related method, among other things, are disclosed. In at least one embodiment, the system includes first, second, and intermediate slab formations, the last of which has formed therewithin a microfluidic channel, a lens structure arranged proximate the microfluidic channel, and a light conveying structure arranged proximate to the lens structure. The lens structure is configured to direct a portion of light to proceed between the channel and the conveying structure. The intermediate slab formation is sandwiched between the other two slab formations. In at least another embodiment, the system includes a microfluidic prism arranged proximate to the second end of a light conveying structure. Light emanating from a microfluidic channel is provided to the conveying structure at the first end, conveyed to the second end, and provided to the prism, which outputs a plurality of portions of the light at different frequencies in different directions.Type: ApplicationFiled: May 14, 2008Publication date: January 29, 2009Inventors: Jessica Godin, Yu-Hwa Lo
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Patent number: 7453646Abstract: Fluidic adaptive lens devices, and systems employing such lens devices, along with methods of fabricating and operating such lens devices, are disclosed. In one embodiment, a lens material is optimally selected to provide one or more desired characteristics for a variety of applications related to adaptive lens devices. In another embodiment, a fluidic medium is optimally chosen to provide one or more desired characteristics for a variety of applications related to adaptive lens devices.Type: GrantFiled: March 7, 2007Date of Patent: November 18, 2008Assignee: The Regents of the University of CaliforniaInventor: Yu-Hwa Lo
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Publication number: 20070201138Abstract: Fluidic adaptive lens devices, and systems employing such lens devices, along with methods of fabricating and operating such lens devices, are disclosed. In one embodiment, a lens material is optimally selected to provide one or more desired characteristics for a variety of applications related to adaptive lens devices. In another embodiment, a fluidic medium is optimally chosen to provide one or more desired characteristics for a variety of applications related to adaptive lens devices.Type: ApplicationFiled: March 7, 2007Publication date: August 30, 2007Inventor: Yu-Hwa Lo
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Patent number: 6806114Abstract: A process for creating a broadly tunable Distributed Bragg Reflector (DBR) with a reduced recombination rate. According to the current invention, this may be achieved by creating electron confinement regions and hole confinement regions in the waveguide of the DBR. Preferably, this is achieved by engineering the band gaps of the DBR waveguide and cladding materials. Preferably, the materials selected for use in the DBR may be lattice matched. Alternately, two or more thin electron confinement regions and two or more thin hole confinement regions may be created to take advantage of strain compensation in thinner layers thereby broadening the choices of materials appropriate for use in creating a broadly tunable DBR. Alternately, graded materials and/or graded interfaces may be created according to alternate processes according to the current invention to provide effective electron and/or hole confinement regions in various DBR designs.Type: GrantFiled: November 7, 2001Date of Patent: October 19, 2004Assignee: Nova Crystals, Inc.Inventor: Yu-Hwa Lo
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Patent number: 6583482Abstract: An avalanche photodetector (APD) is made from composite semiconductor materials. The absorption region of the APD is formed in a n-type InGaAs layer. The multiplication region of the APD is formed in a p-type silicon layer. The two layers are bonded together. The p-type silicon layer may be supported on an n+ type silicon substrate. A p-n junction formed at the interface between the silicon layer and the substrate. Alternatively, the n-type InGaAs layer may be supported on an InP substrate. In this case, a p-n junction is formed by making n-doped surface regions in the p-type silicon superlayer. In either case, the p-n junction is reverse biased for avalanche multiplication of charge carriers. The maximum of the electric field distribution in the APD under reverse bias operating conditions is located at p-n junction. This maximum is at a distance equal to about the thickness of the p-type silicon layer away from the absorption region.Type: GrantFiled: October 3, 2001Date of Patent: June 24, 2003Inventors: Alexandre Pauchard, Yu-Hwa Lo
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Patent number: 6459709Abstract: A wavelength-tunable distributed feedback (DFB) laser is disclosed where the lasing wavelength can be adjusted by adjusting the bias current of the laser diode. Since the output power of the laser diode also changes with the bias current, a one-to-one correspondence between the lasing wavelength and the output power of the laser can be established. Consequently, the lasing wavelength can be measured directly from the photocurrent of a power monitoring detector facing the back-end of the laser diode. This provides an extremely simple method for wavelength monitoring.Type: GrantFiled: January 31, 2001Date of Patent: October 1, 2002Assignee: Nova Crystals, Inc.Inventors: Yu-Hwa Lo, Steven Gregg Hummel, Chenting Lin, Chau-Hong Kuo, Mei-Ling Shek-Stefan, Sergey V. Zaytsev
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Patent number: 6459716Abstract: An integrated surface emitting laser and modulator device is disclosed that includes a detector for monitoring the optical power output of the laser and another detector for monitoring an extinction ratio of the modulator. A cleave physically and electrically separates the laser from the modulator device. The device has a collimating lens disposed on a top surface.Type: GrantFiled: February 1, 2001Date of Patent: October 1, 2002Assignee: Nova Crystals, Inc.Inventors: Yu-Hwa Lo, Zuhua Zhu, Shabbir Bashar
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Publication number: 20020131465Abstract: An integrated surface emitting laser and modulator device is disclosed that includes a detector for monitoring the optical power output of the laser and another detector for monitoring an extinction ratio of the modulator. A cleave physically and electrically separates the laser from the modulator device. The device has a collimating lens disposed on a top surface.Type: ApplicationFiled: February 1, 2001Publication date: September 19, 2002Inventors: Yu-Hwa Lo, Zuhua Zhu, Shabbir Bashar
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Publication number: 20020101898Abstract: A wavelength-tunable distributed feedback (DFB) laser is disclosed where the lasing wavelength can be adjusted by adjusting the bias current of the laser diode. Since the output power of the laser diode also changes with the bias current, a one-to-one correspondence between the lasing wavelength and the output power of the laser can be established. Consequently, the lasing wavelength can be measured directly from the photocurrent of a power monitoring detector facing the back-end of the laser diode. This provides an extremely simple method for wavelength monitoring.Type: ApplicationFiled: January 31, 2001Publication date: August 1, 2002Applicant: Nova Crystals, Inc.Inventors: Yu-Hwa Lo, Steven Gregg Hummel, Chenting Lin, Chau-Hong Kuo, Mei-Ling Shek-Stefan, Sergey V. Zaytsev
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Patent number: 6406795Abstract: A compliant substrate for the formation of semiconductor devices includes a crystalline base layer and a thin-film crystalline layer on and loosely bonded to the base layers. The thin-film layer has a high degree of lattice flexibility. A compliant substrate for formation of semiconductor devices may also include a crystalline base layer, and, on the base layer, a thin film layer having a lattice constant different from the lattice constant of the base layer. A method for formation of a compliant substrate for formation of semiconductor devices includes forming a thin film layer on a first substrate, bonding a first surface of the thin film layer to a surface of a second substrate having a lattice constant different from the lattice constant of the thin film layer either with or without twist bonding, and removing the first substrate to expose a second surface of the thin film layer.Type: GrantFiled: October 25, 1999Date of Patent: June 18, 2002Assignee: Applied Optoelectronics, Inc.Inventors: Wen-Yen Hwang, Yucai Zhou, Zuhua Zhu, Yu-Hwa Lo
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Publication number: 20020070125Abstract: A method is disclosed for separating a semiconductor epitaxial structure from an insulating growth substrate. The method utilizes electrochemical anodic reactions to remove a thin etch layer disposed near the growth interface. The thin etch layer can be an intentional layer made of a material different from the epitaxial structure and/or can include a material with a high defect density. The method can be applied in the fabrication of optoelectronic and electronic devices from III-V materials, in particular gallium-nitride based materials.Type: ApplicationFiled: December 13, 2000Publication date: June 13, 2002Applicant: Nova Crystals, Inc.Inventors: Tuoh-Bin Ng, David Crouse, Zuhua Zhu, Yu-Hwa Lo
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Publication number: 20020068373Abstract: This invention describes a method for fabricating light-emitting diodes with an improved external quantum efficiency on a transparent substrate. The LED device structure is mounted face-down on and bonded to a handling wafer. The LED dies on the transparent substrate are separated by applying mutually aligned separation cuts from both sides of the transparent substrate and by then cutting through the handling wafer and the substrate wafer. This method allow the use of substrates that are difficult to thin and cleave. Contacts can be applied from one side of the devices only. The method is suitable for low cost high volume manufacturing.Type: ApplicationFiled: December 1, 2000Publication date: June 6, 2002Applicant: Nova Crystals, Inc.Inventors: Yu-Hwa Lo, Zuhua Zhu, Tuoh-Bin Ng
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Publication number: 20020066938Abstract: An avalanche photodetector (APD) is made from composite semiconductor materials. The absorption region of the APD is formed in a n-type InGaAs layer. The multiplication region of the APD is formed in a p-type silicon layer. The two layers are bonded together. The p-type silicon layer may be supported on an n+ type silicon substrate. A p-n junction formed at the interface between the silicon layer and the substrate. Alternatively, the n-type InGaAs layer may be supported on an InP substrate. In this case, a p-n junction is formed by making n-doped surface regions in the p-type silicon superlayer. In either case, the p-n junction is reverse biased for avalanche multiplication of charge carriers. The maximum of the electric field distribution in the APD under reverse bias operating conditions is located at p-n junction. This maximum is at a distance equal to about the thickness of the p-type silicon layer away from the absorption region.Type: ApplicationFiled: October 3, 2001Publication date: June 6, 2002Applicant: Nova Crystals, Inc.Inventors: Alexandre Pauchard, Yu-Hwa Lo
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Publication number: 20020063303Abstract: A planar avalanche photodetector (APD) is fabricated by forming a, for example, InGaAs absorption layer on a p+-type semiconductor substrate, such as InP, and wafer-bonding to the absorption layer a second p-type semiconductor, such as Si, to form a multiplication layer. The layer thickness of the multiplication layer is substantially identical to that of the absorption layer. A region in a top surface of the p-type Si multiplication layer is doped n+-type to form a carrier separation region and a high electric field in the multiplication region. The APD can further include a guard-ring to reduce leakage currents as well as a resonant mirror structure to provide wavelength selectivity. The planar geometry furthermore favors the integration of high-speed electronic circuits on the same substrate to fabricate monolithic optoelectronic transceivers.Type: ApplicationFiled: December 6, 2000Publication date: May 30, 2002Applicant: Nova Crystals, Inc.Inventors: Alexandre Pauchard, Yu-Hwa Lo
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Publication number: 20020061648Abstract: A method for producing a stress-engineered substrate includes selecting first and second materials for forming the substrate. An epitaxial material for forming a heteroepitaxial layer is then selected. If the lattice constant of the heteroepitaxial layer (aepi) is greater than that (asub) of the immediate substrate layer the epitaxial layer is deposited on, then the epitaxial layer is kept under “compressive stress” (negative stress) at all temperatures of concern. On the other hand, if the lattice constant of the heteroepitaxial layer (aepi) is less than that (asub) of the immediate substrate layer the epitaxial layer is deposited on, then the epitaxial layer is kept under “tensile stress” (positive stress). The temperatures of concern range from the annealing temperature to the lowest temperature where dislocations are still mobile.Type: ApplicationFiled: June 6, 2001Publication date: May 23, 2002Applicant: Nova Crystals Inc.Inventors: Yu-Hwa Lo, Felix Ejeckam
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Patent number: 6384462Abstract: A planar avalanche photodetector (APD) is fabricated by forming a, for example, InGaAs absorption layer on a p+-type semiconductor substrate, such as InP, and wafer-bonding to the absorption layer a second p-type semiconductor, such as Si, to form a multiplication layer. The layer thickness of the multiplication layer is substantially identical to that of the absorption layer. A region in a top surface of the p-type Si multiplication layer is doped n+-type to form a carrier separation region and a high electric field in the multiplication region. The APD can further include a guard-ring to reduce leakage currents as well as a resonant mirror structure to provide to wavelength selectivity. The planar geometry furthermore favors the integration of high-speed electronic circuits on the same substrate to fabricate monolithic optoelectronic transceivers.Type: GrantFiled: December 6, 2000Date of Patent: May 7, 2002Assignee: Nova Crystals, Inc.Inventors: Alexandre Pauchard, Yu-Hwa Lo
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Publication number: 20020048900Abstract: The method of the present invention is used to join two dissimilar materials together, and particularly to transfer a film to a substrate when the difference in thermal expansion coefficients between the film and the substrate is very big. A hydrophilic surface is created on one material and an atmosphere reactive metal element is deposited on the surface of another material. When the materials are tightly contacted, with the reactive element pressed against the hydrophilic surface, the reactive metal element reacts with the moisture from the hydrophilic surface at room temperature. Strong bonds form during the reaction joining the two materials together. Because the procedure takes place at room temperature, extremely low stress is built in. The film joining is successful even with a big thermal expansion coefficient difference between the materials, such as exist between GaAs and silicon and between silicon and sapphire.Type: ApplicationFiled: May 23, 2001Publication date: April 25, 2002Applicant: Nova Crystals, Inc.Inventors: Yu-Hwa Lo, Jizhi Zhang
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Publication number: 20020003824Abstract: A semiconductor surface-emitting laser device has a lasing section and a beam-deflecting section. The two sections are assembled adjacent to each other in close optical and physical proximity. The lasing section includes a horizontal laser cavity having faceted ends. The cavity emits horizontally propagating a light beam through one faceted end into the adjoining beam-deflecting section. The beam-deflecting section includes two mirror surfaces. The two mirror surfaces are oriented such that the horizontally propagating light beam is redirected to propagate vertically toward the top surface of the laser device by sequential reflections off of the two mirrors. A beam-shaping micro-optics lens is disposed on the top surface of the beam-deflecting section. The micro-optic lens collimates the vertically propagating redirected light beam to generate an output beam emitted from the top surface of the laser device.Type: ApplicationFiled: May 31, 2001Publication date: January 10, 2002Inventors: Yu-Hwa Lo, Zuhua Zhu, Chenting Lin
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Publication number: 20010052535Abstract: A method of semiconductor eutectic alloy metal (SEAM) technology for integration of heterogeneous materials and fabrication of compliant composite substrates takes advantage of eutectic properties of alloys. Sub1 and Sub2 are used to represent the two heterogeneous materials to be bonded or composed into a compliant composite substrate. For the purpose of fabricating compliant composite substrate, the first substrate material (Sub1) combines with the second substrate material (Sub2) to form a composite substrate that controls the stress in the epitaxial layers during cooling. The second substrate material (Sub2) controls the stress in the epitaxial layer grown thereon so that it is compressive during annealing. A joint metal (JM) with a melting point of Tm is chosen to offer variable joint stiffness at different temperatures. JM and Sub1 form a first eutectic alloy at a first eutectic temperature Teu1 while JM and Sub2 form a second eutectic alloy at a second eutectic temperature Teu2.Type: ApplicationFiled: March 5, 2001Publication date: December 20, 2001Applicant: Nova Crystals, Inc.Inventors: Zuhua Zhu, Tuoh-Bin Ng, Yu-Hwa Lo