An electromagnetic immune tissue invasive system includes a primary device housing. The primary device housing having a control circuit therein. A shielding is formed around the primary device housing to shield the primary device housing and any circuits therein from electromagnetic interference. A lead system transmits and receives signals between the primary device housing. The lead system is either a fiber optic system or an electrically shielded electrical lead system.

Electromagnetic interference immune tissue invasive system

An optical sense signal generator for medical device's having a photonic catheter containing optical conductors conducting light energy in two directions between electronics at a catheter proximal end and electrical stimulation and sensing components at a catheter distal end. An optical unit receives light delivered from the catheter proximal end and transmits a first portion of the light while diverting a second portion of the light. The transmitted light is fed to an opto-electrical converter for conversion into electrical stimulation signals. The diverted light is directed to one or more optical modulators that modulate the diverted light output under an applied electrical signal. An electrical circuit generates electrical sense signals corresponding to one or more sensed physiological conditions and provides the signals to the optical modulator(s). This results in modulation of the diverted light output into optical sense signals that are transmitted to the catheter proximal end.

Mri-compatible medical device with passive generation of optical sensing signals

A cardiac assist device containing a device for connecting the cardiac assist device to a heart, for furnishing electrical impulses from the cardiac assist device to the heart, for ceasing the furnishing of electrical impulses to the heart, for receiving pulsed radio frequency fields, for transmitting and receiving optical signals, and for protecting the heart and the cardiac assist device from currents induced by the pulsed radio frequency fields. The cardiac assist device contains a control circuit comprised of a parallel resonant frequency circuit.

MRI-compatible implantable device

An implantable device used to monitor and maintain at least one physiologic function, which is capable of operating in the presence of damaging electromagnetic interference. The implantable device includes primary and secondary modules, each independently protected from EMI damage via at least one shielding and/or filtering, and a non-electrical communication device for communicating in at least one direction between the primary and the secondary modules. The primary module, in response to input from electrical sensing leads, activates the secondary module in a failsafe mode. In the failsafe mode, the secondary module carries out a physiologic function upon activation and in the presence of electromagnetic interference.

MRI-resistant implantable device

A process for stimulating tissue such as cardiac tissue, nerve tissue, and brain tissue. In one step of the process, there is delivered an electrical stimulating signal to the tissue that contains from about 10 to about 1,000 individual pulses. Each individual pulse has a duration of from about one microsecond to about 100 microseconds and is discontinuous, with a spacing between adjacent pulses of at least from about 1 microsecond to about 100 microseconds. The individual pulses have a voltage of from about 10 millivolts to about 100 volts.

Pulsewidth electrical stimulation

A unidirectional electrooptic modulator based on an asymmetrical highly multi-mode waveguide coupler is proposed. Firstly, the energy distributions of all the modes within two highly multi-mode waveguides are analyzed with eigenstate theory. Then, to achieve high switching performance in a guided-wave coupler, a dumping wall is placed on the larger waveguide of an asymmetric pair of waveguides, so that the larger waveguide has a dumping effect. This dumping effect makes the asymmetric highly multi-mode waveguide coupler possess a highly efficient unidirectional coupling process. Due to the large cross-section of the waveguide, a new modulation electrode structure is built. Based on this dumping effect, the unidirectional coupling process is theoretically modeled. Furthermore, in both scenarios, i.e., the unmodulated state and the electrooptically modulated state, the unidirectional coupling efficiencies are studied. As a result, not only can a high unidirectional coupling efficiency of 100% be achieved, but a high electrooptic modulation depth more than 90% can also be implemented in theory, and a high thermooptic modulation depth more than 90% under a low modulation voltage of 30 volts is also experimentally achieved. This device can be used for multi-mode optical interconnection systems such as data communication and fiber sensor networks.

David Sun

Papers

High-performance unidirectional electrooptic modulator based on polymeric highly multi-mode waveguides