摘要:
An electro-optic modulator modulates light in response to a life-form bio-potential to provide a bio-potential modulated light output. Modulation can be carried out as a result of capacitive coupling with the bio-potential. Phase, polarization, and intensity light modulation can be used. The light output can then be converted to electronic form for further processing. An optical power splitter is used to split light into multiple portions that are converted to electrical form. A pilot tone is used to achieve high sensitivity and synchronize multiple electro-optic modulators while phase modulation can be used to reduce noise in the bio-potential signal. Low-coherent light may be used as the light source. A housing is provided that can be hermetically-sealed and provided with electro-magnetic shielding.
摘要:
An opto-electric device for measuring the root mean square value of an alternating current voltage has: a) an electric field-to-light-to-voltage converter having 1) a light source; 2) an electro-optic material: (a) receiving light from the light source; (b) modulating said light; and (c) providing a modulated light output; 3) an electric field applied to the electro-optic crystal to modulate the light from the light source to produce the modulated light output; b) an optical receiver for receiving and converting the modulated output light from the electro-optic material to a first voltage that is proportional to a square of the electric field applied to the electro-optic material; c) an averager circuit receiving the first voltage and providing a second voltage that is proportional to the average of said square of said electric field over a period of time; and d) an inverse ratiometric circuit receiving the second voltage from the averager circuit and returning a third voltage that is an inverse voltage of the second voltage to the electric field-to-light-to-voltage converter to produce an output voltage that is the root mean square voltage of the applied electric field. The device uses a Mach-Zehnder interferometer operating as a square law device and features a housing for maintaining the interferometer at constant temperature using a temperature control unit. A nulling circuit is provided to maintain the interferometer at it null operating point as are calibration circuits to correct for voltage amplitude and frequency changes.
摘要:
An opto-electric device for measuring the root mean square value of an alternating current voltage comprises: a) an electric field-to-light-to-voltage converter having 1) a light source; 2) an electro-optic material: (a) receiving light from the light source; (b) modulating said light; and (c) providing a modulated light output; 3) an electric field applied to the electro-optic crystal to modulate the light from the light source to produce the modulated light output; b) an optical receiver for receiving and converting the modulated output light from the electro-optic material to a first voltage that is proportional to a square of the electric field applied to the electro-optic material; c) an averager circuit receiving the first voltage and providing a second voltage that is proportional to the average of said square of said electric field over a period of time; and d) an inverse ratiometric circuit receiving the second voltage from the averager circuit and returning a third voltage that is an inverse voltage of the second voltage to the electric field-to-light-to-voltage converter to produce an output voltage that is the root mean square voltage of the applied electric field. The device uses a Mach_Zehnder interferometer operating a a square law device and features a housing for maintaining the interferometer at constant temperature using a temperature control unit. A nulling circuit is provided to maintain the interferometer at it null operating point as are calibration circuits to correct for voltage amplitude and frequency changes.
摘要:
Improved thermooptical sensing devices are provided wherein at various predetermined sectons of an optical fiber is juxtaposed a material characterized by a temperature dependent index of refraction. This material forms a temperature sensitive area which controls the transmission of light through the optical fiber thereby allowing detection of temperature changes along the fiber. The materials may be crystalline thermoplastic polymers, modified organic polymers containing inorganic modifiers, polymer systems containing discrete phases of organic polymers and inorganic additives or thermochromic inorganic compounds.
摘要:
A signal transmission system impresses phase-modulated signals on to a multimode optical fibre waveguide 1. In order to overcome the effects of fading caused by small random changes in the parameters of the fibre the signals from different modes are all combined to derive a resulting signal which is detected in a common detector 23. The signals may be combined by a vibrating mirror 21 which sweeps the emergent beam across detector 23. Alternatively the tip of fibre 1 may be vibrated to achieve a similar effect.
摘要:
A telecommunication system has a laser-energized multimode optical fibre highway. Data is entered on to the highway by means of a series of modulators each operating at a different subcarrier frequency. At the far end of the highway demodulation is carried out be a quadrant photodetector which applies each of its outputs to a respective set of channels. Each channel in a set has a band pass filter centered on a subcarrier frequency followed by a non-linear device. The signals from all the channels of different sets carrying the same subcarrier frequency are combined and the signals passed through band pass filters centered on the second harmonic of the subcarrier frequency.
摘要:
An optical modulator has optical channels formed in a waveguide substrate in which two of the waveguide channel branches have reverse polarity relative to each other. In addition, the optical modulator has at least one of the following: 1) an electronic signal electrode and an electronic ground electrode are placed in proximity with opposite faces of the waveguide substrate, 2) a portion of said waveguide substrate is removed to afford a reduced electronic signal refractive index, and 3) the waveguide substrate has a fixing substrate attached to it with the refractive index of the fixing substrate lower than said refractive index of the waveguide substrate.
摘要:
High-impedance optical electrodes modulate light in response to a life-form bio-potential and then converts the modulated light to an electrical signal that provides traditional EEG and EEC type output. Light splitters are used to provide multiple electrodes and an electronic reference source. A pilot tone is used to achieve high sensitivity and synchronize multiple units while an optical phase-shift modulator is used to reduce optical noise.
摘要:
The invention relates to an electric field sensor useful in detecting and measuring wideband transient electrical responses by means of an integrated optical waveguide interferometer. Mach-Zehnder devices are produced wherein one waveguide channel has been reverse poled, or has domain inversion, preferably by means of titanium diffusion into said waveguide channel. Also produced is an electrode-less optical interferometer modulator by which an optical output signal is modulated at the same frequency as an applied electric field.
摘要:
The presence of a signal is sensed by a signal transducer around which an optical fibre is wrapped so that the length of the fibre is modulated by any signal present. A laser supplies coherent light to one end of the fibre and a homodyne detector is provided at the other end. Discontinuities at both ends of the fibre cause multiple reflections which produce differential phase modulations of the signal. The detected signal contains a large number of frequency components and the peak frequency is related to the amplitude of the original signal. The peak frequency is indicated by a suitable filter arrangement.