Abstract: The present invention relates to angle-tuned (AT) ring coil devices to reduce the individual coil footprint and improve depth-spread characteristics of transcranial magnetic stimulation (TMS) systems. The AT coil device includes multiple stacked coils, which enhances field strength, reduces the footprint, and increases the field penetration depth by modifying its geometric distribution. Moreover, the AT coil devices demonstrated superior performance for multisite stimulation due to their smaller footprint, making them suitable for multisite stimulations of inter and intra-hemispheric brain regions with an improved spread and less electric field divergence.

Abstract: Disclosed is an electromagnetic coil system for use during transcranial or transdermal stimulation procedures, in which an electrically conductive coil wraps around a magnetic core at an oblique wrapping angle to provide a more directed focal spot size at a given depth inside of, for example, a patient's body. In certain configurations, the electrically conductive coil may be adjustable with respect to the magnetic core, such that the wrapping angle of the electrically conductive coil may be modified to, in turn, adjust the focal spot size of the induced electric field generated by the system as may desired to concentrate the field at a particularly desired location.

Abstract: Methods and systems to control magnetic fields and magnetic field induced currents, and to provide stimulations within a patient's body, e.g.: deep brain stimulation, in a non-invasive manner and with greater focus and control than has been afforded by prior known methods and systems. An array of magnetic coils is provided and positionable about a portion of a patient's body, and are configured to create a small region of a magnetic hole, or configured to create a small region of concentrated magnetic field strength, or their combination, and at depths within the patient's body in a focused region and sparing the surrounding tissues of the focused region, that have previously not been receptive to non-invasive TMS methods, which are either focused but can affect only the surface and shadow areas, or that can reach certain depths but by doing so only through affecting large surface areas and deep tissue areas.

Abstract: Disclosed are systems, devices and methods for detecting and measuring TMS-induced electrical fields. In accordance with certain aspects of an embodiment of the invention, a TMS sensor probe is provided having a field detector, a first electrical connection connecting the field detector to either a power source or a processor, and a second electrical connection connecting the field detector to a processor. The field detector is configured to measure a characteristic of a TMS-induced electrical field at the location of the field detector, and the processor is configured to receive the measured characteristic of the induced electrical fields and display a human-readable depiction of a calculated induced electrical field. A system using such a sensor probe to calibrate a TMS-induced electrical field is also provided, including the foregoing sensor probe, and a magnetic field generator.

Abstract: Disclosed is an electromagnetic coil system for use during transcranial or transdermal stimulation procedures, in which an electrically conductive coil wraps around a magnetic core at an oblique wrapping angle to provide a more directed focal spot size at a given depth inside of, for example, a patient's body. In certain configurations, the electrically conductive coil may be adjustable with respect to the magnetic core, such that the wrapping angle of the electrically conductive coil may be modified to, in turn, adjust the focal spot size of the induced electric field generated by the system as may desired to concentrate the field at a particularly desired location.

Abstract: The present invention discloses methods and systems to control magnetic fields and magnetic field induced currents, and more particularly to provide stimulations within a patient's body, such as deep brain stimulation, in a non-invasive manner and with greater focus and control than has been afforded by prior known methods and systems. In accordance with certain aspects of an embodiment, an array of magnetic coils is provided and positionable about a portion of a patient's body. During operation, at least some of the magnetic coils function as DC coil pairs configured to generate a DC magnetic field, while at least some DC coil of the other magnetic coils function as transient magnetic field generators to generate an induced current within a portion of the patient's body, such as in a region of the patient's brain.

Abstract: Methods and systems to control magnetic fields and magnetic field induced currents, and to provide stimulations within a patient's body, e.g.: deep brain stimulation, in a non-invasive manner and with greater focus and control than has been afforded by prior known methods and systems. An array of magnetic coils is provided and positionable about a portion of a patient's body, and are configured to create a small region of a magnetic hole, or configured to create a small region of concentrated magnetic field strength, or their combination, and at depths within the patient's body in a focused region and sparing the surrounding tissues of the focused region, that have previously not been receptive to non-invasive TMS methods, which are either focused but can affect only the surface and shadow areas, or that can reach certain depths but by doing so only through affecting large surface areas and deep tissue areas.

Abstract: Disclosed are systems, devices and methods for detecting and measuring TMS-induced electrical fields. In accordance with certain aspects of an embodiment of the invention, a TMS sensor probe is provided having a field detector, a first electrical connection connecting the field detector to either a power source or a processor, and a second electrical connection connecting the field detector to a processor. The field detector is configured to measure a characteristic of a TMS-induced electrical field at the location of the field detector, and the processor is configured to receive the measured characteristic of the induced electrical fields and display a human-readable depiction of a calculated induced electrical field. A system using such a sensor probe to calibrate a TMS-induced electrical field is also provided, including the foregoing sensor probe, and a magnetic field generator.

Abstract: The present invention discloses methods and systems to control magnetic fields and magnetic field induced currents, and more particularly to provide stimulations within a patient's body, such as deep brain stimulation, in a non-invasive manner and with greater focus and control than has been afforded by prior known methods and systems. In accordance with certain aspects of an embodiment, an array of magnetic coils is provided and positionable about a portion of a patient's body. During operation, at least some of the magnetic coils function as DC coil pairs configured to generate a DC magnetic field, while at least some DC coil of the other magnetic coils function as transient magnetic field generators to generate an induced current within a portion of the patient's body, such as in a region of the patient's brain.

Abstract: A multi-quantum well optical waveguide structure comprises a plurality of active regions including quantum wells with different gain peak wavelengths to provide an ultra broadband optical gain spectrum. Two adjacent sets of active regions having a large band gap difference are connected by a tunneling injection layer to provide smooth electron transport. Single transverse-mode operation is obtained by narrowly tapering the width of the multi-quantum well optical waveguide from the center to the two ends. Higher-order modes are suppressed at the output of the tapered waveguide, even though the center waveguide portion supports higher-order modes. In this way, the multi-quantum well optical waveguide can be utilized for ultra broadband optical amplification using a single mode fiber.

Abstract: The present invention provides a thin-film semiconductor laser device that utilizes a double-sided heat removal technique and architecture. The term “thin-film semiconductor laser”, as used herein, refers to a semiconductor laser having a p-i-n structure, in which the thickness of the p-layer is no more than 10 times the thickness of the n-layer, or the thickness of the n-layer is no more than 10 times the thickness of the p-layer. The thin-film semiconductor laser device of the present invention exhibits a p-n junction temperature that is only a few degrees higher than the sub-mount temperature. This greatly reduces the thermally related losses and thermally generated stresses of the chip.

Abstract: A multi-quantum well optical waveguide structure comprises a plurality of active regions including quantum wells with different gain peak wavelengths to provide an ultra broadband optical gain spectrum. Two adjacent sets of active regions having a large band gap difference are connected by a tunneling injection layer to provide smooth electron transport. Single transverse-mode operation is obtained by narrowly tapering the width of the multi-quantum well optical waveguide from the center to the two ends. Higher-order modes are suppressed at the output of the tapered waveguide, even though the center waveguide portion supports higher-order modes. In this way, the multi- quantum well optical waveguide can be utilized for ultra broadband optical amplification using a single mode fiber.

Abstract: An RF-lightwave transmitter performs successive conversions of an information-bearing input signal in order to generate an output signal suitable for transmission in a wireless communications system. The transmitter includes a high-efficiency FM laser connected to a FM discriminator. In operation, the laser converts an RF signal into a frequency-modulated optical signal, and the discriminator converts this signal into an amplitude-modulated optical signal. The discriminator performs its conversion using a high slope-efficiency linear transfer function which ensures that the AM optical signal varies in accordance with a desired operational performance. The transmitter also includes a photodiode which converts the AM signal output from the optical discriminator back into an RF signal for transmission. Experimental results demonstrated that a transmitter of this type is able to realize greater than 10 dB RF insertion gain at less than 0 dBm optical power, with a high spurious-free dynamic range and low noise.

Abstract: An optical gain medium, and a method for forming the same, is provided that exhibits lower wavelength crosstalk when configured as an optical amplifier than prior art optical gain media. The optical gain medium of the present invention includes a buried heterostructure waveguide fabricated in a multiple quantum well (MQW) region. The MQW region in which the buried heterostructure waveguide is located exhibits a continuously changing bandgap as a function of position along the waveguide direction, preferably such that the gain provided by the optical gain medium changes exponentially as a function of position along the waveguide direction. In a preferred embodiment, the MQW region in which the buried heterostructure waveguide is buried is grown using a selective-area-growth (SAG) technique, and is made up of at least two quantum wells, with at least one of the quantum wells having a size and composition that vary as a function of position along the waveguide direction.

Abstract: A broadband medium (100) for a laser (300) having multiple quantum wells (130).

Abstract: An improved thermally tunable system is provided. The improved thermally tunable system includes a thermally tunable apparatus including a first portion and a second portion, a heater configured to thermally tune the apparatus, and a heat sink disposed adjacent to the apparatus, wherein thermal flow is controlled to pass from the heater through the first portion of the apparatus, and then through the second portion into the heat sink, such that a temperature of the second portion remains substantially constant or within a predetermined range. A thermally conductive material is provided between the second portion of the apparatus and the heat sink. A thermally insulating material is provided between the first portion of the apparatus and the heat sink.

Abstract: A system and method for compensating for unwanted modes in multimode fiber transmissions includes a detector that receives an optical signal transmitted through a multimode optical fiber and converts the transmitted optical signal to a detector signal, an adaptive equalizer that generates an adaptive equalizer signal that, when combined with the detector signal, compensates for unwanted modes in the detector signal, and an adder that combines the adaptive equalizer signal with the detector signal.

Abstract: A system and method of testing multiple edge-emitting lasers on a common wafer is provided. This is accomplished by providing, for each edge-emitting laser on a common fabrication wafer, a structure that re-directs a portion of the edge-emitted light from each edge-emitting laser in a direction such that the re-directed portion from each edge-emitting laser can be measured while the edge-emitting lasers are still on the fabrication wafer. Each edge-emitting laser on the fabrication wafer can therefore be easily tested before cleaving or breaking the wafer into multiple pieces.

Abstract: The present invention provides tunable optical system, and a method for forming the same, that exhibits a broader tuning range with fewer components than prior art tunable optical systems. The tunable optical system of the present invention includes a plurality of wavelength routers, each having a different optical channel resolution, optically coupled to a plurality of optical amplifier arrays. The free spectral range of each of the second and subsequent wavelength routers is equal to a total bandwidth of one of its respective grating orders. The system is tuned by selectively activating optical amplifiers in each of the optical amplifier arrays. The tunable optical system of the present invention can be used to make tunable semiconductor emitters, receivers and filters.

Abstract: An improved thermally tunable system is provided. The improved thermally tunable system includes a thermally tunable apparatus including a first portion and a second portion, a heater configured to thermally tune the apparatus, and a heat sink disposed adjacent to the apparatus, wherein thermal flow is controlled to pass from the heater through the first portion of the apparatus, and then through the second portion into the heat sink, such that a temperature of the second portion remains substantially constant or within a predetermined range. A thermally conductive material is provided between the second portion of the apparatus and the heat sink. A thermally insulating material is provided between the first portion of the apparatus and the heat sink.