Abstract: A method and apparatus of OFDR are disclosed, in which a pair of probe signals are launched, on mutually orthogonal channels, into the optical fiber cable that is to be monitored. In a digital processing circuit, phase noise is cancelled from the return signals after detecting them in their respective mutually orthogonal channels and after demodulating them, by combining them such that noise components of the respective demodulated signals are mutually cancelled. In embodiments, a conjugate pair of probe signals are launched, on mutually orthogonal channels, into the optical fiber cable.

Abstract: Disclosed is an optoelectromechanical switch that includes: an optical feedline disposed on an isolation substrate that receives resonator light that is subject to optical communication to a resonator when a cavity length of the resonator supports an electromagnetic mode at the wavelength of the resonator light; a resonator including: a low refractive index optical layer and receives substrate electrical counter potential; a non-conductive spacer; the electrically conductive membrane and that receives a membrane electrical potential and deflects toward and away from the electrically conductive high-index optical waveguide based on a difference in potential between the membrane electrical potential and the substrate electrical counter potential; the cavity length that is variable and under electromechanical control.

Abstract: A fiber-optic communication system having two optical channels characterized by different respective group velocities. In an example embodiment, the system comprises an optical receiver capable of measuring a difference in the time of arrival thereto, by way of the two optical channels, of the corresponding signal disturbances caused by a remote ambient event, such as an earthquake or a lightning strike. A signal processor of the receiver can then use the measured time-of-arrival difference to estimate the distance, along the fiber, to the location of the remote ambient event. In some example embodiments, the two optical channels may be different wavelength channels or different spatial modes of a multimode fiber. In some example embodiments, at least one of the two channels may be a payload-data-bearing channel.

Abstract: Disclosed is an optoelectromechanical switch that includes: an optical feedline disposed on an isolation substrate that receives resonator light that is subject to optical communication to a resonator when a cavity length of the resonator supports an electromagnetic mode at the wavelength of the resonator light; a resonator including: a low refractive index optical layer and receives substrate electrical counter potential; a non-conductive spacer; the electrically conductive membrane and that receives a membrane electrical potential and deflects toward and away from the electrically conductive high-index optical waveguide based on a difference in potential between the membrane electrical potential and the substrate electrical counter potential; the cavity length that is variable and under electromechanical control.