Abstract: An output coupler can be used to couple multiple channels of light from a semiconductor waveguide to an optical fiber for wavelength division multiplexing. To couple light of a wide bandwidth (e.g., equal to or greater than 100 nm), two symmetrical gratings on two sides of a Fabry Perot cavity is used. The two symmetrical gratings are optimized to both reflect light for a Fabry Perot resonator and couple light out of the semiconductor waveguide.

Abstract: A system for optical communication comprises a waveguide (110) and an optical coupler (100). The waveguide (110) is provided with a core of higher refractive index material disposed on a substrate (204). The optical coupler (100) is used to couple light between an integrated optical waveguide (110) and an optical fiber (120) with high coupling efficiency. The optical coupler (100) comprises a first grating (104) having a first set of ridges (224) separated by a first set of trenches (220) and a second grating (108) having a second set of ridges (234) separated by a second set of trenches (230). The first grating (104) is formed in the core of the waveguide (110). The second set of ridges (234) are offset from the first set of ridges (224). A method for fabricating the optical coupler (100) is also provided.

Abstract: The invention relates to a magnetically coupled charging system and method. The magnetically coupled charging system comprises: a resonant inverter; a split core transformer configured to receive a resonant power from the resonant inverter; and a rectifier assembly configured to receive a transformed resonant power from the split core transformer and transmit the transformed resonant power to a to-be-charged battery; the split core transformer comprising a primary winding and a secondary winding, wherein the primary and secondary windings are split from each other, the resonant inverter and the primary winding of the split core transformer are arranged in an onshore charging system, the rectifier assembly and the secondary winding of the split core transformer are arranged in an onboard charger. The invention has the following advantages of: eliminating the risk of electric shock and short circuit fault at a connection point and eliminating an arcing or sparking problem.

Abstract: We describe a high coupling-efficiency waveguide grating coupler for use in the optical interface between a planar multimode waveguide and a multimode optical fiber in mode division multiplexed optical communication systems. The multimode waveguide grating coupler can launch light from the different modes of the planar waveguide into the different modes of the multimode optical fiber and vice-versa. A silicon based multimode waveguide grating coupler was used to couple two polarizations of a multimode silicon waveguide into the LP01 mode and LP11 mode from a step index multi-mode fiber (MMF). Simulations of the preliminary design predicted the coupling efficiency to be ?4.3 dB for LP01 mode and ?5.0 dB for the LP11 mode. Experimental coupling efficiency of ?4.9 dB and ?6.1 dB were obtained for LP01 and LP11, respectively. The multiplexer can be passive.

Abstract: An output coupler can be used to couple multiple channels of light from a semiconductor waveguide to an optical fiber for wavelength division multiplexing. To couple light of a wide bandwidth (e.g., equal to or greater than 100 nm), two symmetrical gratings on two sides of a Fabry Perot cavity is used. The two symmetrical gratings are optimized to both reflect light for a Fabry Perot resonator and couple light out of the semiconductor waveguide.

Abstract: Low spherical aberration of a Mikaelian lens makes it suitable for focusing off-optical-axis light propagating in higher order modes. A Mikaelian lens can be used as a mode-size converter to expand light in a semiconductor waveguide before coupling light out of the waveguide. For example, a Mikaelian lens can be used in a waveguide to expand light from a 1 ?m wide multimode waveguide to a 20 ?m wide multimode grating coupler in a shorter distance than an adiabatic taper. 3D FDTD simulation results show that an embodiment of a 12 ?m long, subwavelength mode-size converter has comparable first-order mode transmission as a 600 ?m adiabatic taper.

Abstract: We describe a high coupling-efficiency waveguide grating coupler for use in the optical interface between a planar multimode waveguide and a multimode optical fiber in mode division multiplexed optical communication systems. The multimode waveguide grating coupler can launch light from the different modes of the planar waveguide into the different modes of the multimode optical fiber and vice-versa. A silicon based multimode waveguide grating coupler was used to couple two polarizations of a multimode silicon waveguide into the LP01 mode and LP11 mode from a step index multi-mode fiber (MMFs). Simulations of the preliminary design predicted the coupling efficiency to be ?4.3 dB for LP01 mode and ?5.0 dB for the LP11 mode. Experimental coupling efficiency of ?4.9 dB and ?6.1 dB were obtained for LP01 and LP11, respectively. The multiplexer can be passive.

Abstract: Novel and advantageous systems, devices, and methods for pulse wave velocity (PWV) imaging that enable precise central blood pressure (BP) estimation are provided. A multi-sensor array can provide two-dimensional PWV, thereby achieving the PWV imaging and precise central BP estimation. The multi-sensor array can be integrated in daily objects, such as clothing or a bed, which results in noninvasive, continuous, low-cost monitoring of BP that is easy to use and does not require a medical professional. Electrocardiogram imaging, photoplethysmogram imaging, and monitoring for other physiological parameters such as heart rate, SpO2, BP, and respiration, can also be achieved.

Abstract: An optical device and an optical system are provided for coupling of light. The optical device comprises a planar substrate; and an optical waveguiding layer disposed on the planar substrate. The optical waveguiding layer comprises a grating portion for coupling light between a planar waveguide and an optical fiber; and a tapered guiding portion for converting the mode size between the fiber and the planar waveguide. The grating portion comprises a first grating section having non-uniform periods.