A four-dimensional multiplexing method and four-dimensional multiplexing system are provided for optical networks. The method includes receiving sensor data to be transmitted on an optical network. The method also includes encoding the sensor data into an optical signal employing one or more multiplexing systems. The method additionally includes transmitting the optical signal over the optical network. The method further includes decoding the optical signal into the sensor data employing the one or more multiplexing systems. The method also includes controlling an operation of a processor-based machine responsive to the sensor data.

A method and switch are provided for reconfigurable optical space switch. The method includes receiving a control signal, from a controller, to configure a path through the reconfigurable optical space switch. The method also includes applying a voltage to one or more direction changing devices at each intersection between each of the east-west optical waveguides and each of the north-south optical waveguides to form the path through the reconfigurable optical space switch. The method additionally includes receiving an optical signal in one of a plurality of passive waveguides at a beginning of the path, including the plurality of east-west optical waveguides and the plurality of north-south optical waveguides. The method further includes outputting the optical signal out on of the plurality of passive waveguides at an end of the path.

A method and network are provided for a reconfigurable optical sensor network. The method includes configuring, by a controller, the reconfigurable optical sensor network, including one or more reconfigurable optical space switches, for a type of sensor data. The method also includes generating sensor data in the type of sensor data with one or more of a plurality of bidirectional sensors. The method additionally includes sending the sensor data to one or more optical star couplers. The method further includes forwarding the sensor data from one of the one or more optical star couplers to the one of one or more reconfigurable optical space switches.

A system and method for simultaneously addressing multiple parallel distributed fiber optic sensors using a single interrogation instrument is disclosed. One or more of the fiber optic sensors are provided with a non-reflective delay element to prevent an overlap in time between backscatter returns from the distributed fiber optic sensors, thereby allowing the backscatter returns from each sensor to be distinguished based on round-trip transit time.

Some embodiments are directed to a multiplexed fiber sensor for a fiber optic hydrophone array, including a signal receiver configured to receive a signal from the fiber optic hydrophone sensor array and an interferometer. The interferometer is configured to produce a first signal component and a second signal component from the signal received from the hydrophone array, and also provided with a first polarization controller configured to control the polarization of the first signal component and a second polarization controller configured to control the polarization of the second signal component. A modulated carrier signal generator configured to generate a modulated carrier signal component based on the first signal component is also provided. A detector configured to output a demodulated output signal from the modulated signal component and the second signal component is included, wherein the modulated signal component and the second signal component output separately from the interferometer.

An interferometer apparatus for an optical fiber system and method of use is described. The interferometer comprises an optical coupler and optical fibers which define first and second optical paths. Light propagating in the first and second optical paths is reflected back to the optical coupler to generate an interference signal. First, second and third interference signal components are directed towards respective first, second and third photodetectors. The third photodetector is connected to the coupler via a non-reciprocal optical device and is configured to measure the intensity of the third interference signal component directed back towards the input fiber. Methods of use in applications to monitoring acoustic perturbations and a calibration method are described.

A system, apparatus and method directed to detecting damage to an optical fiber. The optical fiber includes core fibers including a plurality of sensors configured to (i) reflect a light signal based on received incident light, and (ii) change a characteristic of the reflected light signal based on experienced strain. The system can include a console having memory storing logic that, when executed, causes operations of providing receiving reflected light signals of different spectral widths of the broadband incident light by one or more of the plurality of sensors, processing the reflected light signals to detect fluctuations of a portion of the optical fiber, and determining a location of the portion of the optical fiber or a defect affecting a vessel in which the portion is disposed based on the detected fluctuations. The portion may be a distal tip of the optical fiber.

A demodulation system for 3D-matrix multi-channel fiber optic sensing includes a wavelength swept optical source that generates an incident light, an optical frequency domain reflector and a balanced detector connected with the wavelength swept optical source through a fiber circulator. The optical frequency domain reflector includes a first optical path and a second optical path with a frequency shifter arranged on one or both of the optical paths. The optical frequency domain reflector outputs incident light to an optical switch module. The optical switch module selectively transmits the incident light to a sensor network as well as transmits the reflection light from the sensor network to the optical frequency domain reflector.

A system and method for evaluating individual Fiber Bragg Grating (FBG) sensors in a multiplexed acoustic sensor system, the system comprising: a broadband pulsed source; a circulator that passes a laser pulse to a multiplexed series of N FBG sensors and one reference Fresnel reflector, wherein said circulator also receives a return N+1 reflection pulse train from the N FBG sensors and one reference Fresnel reflector; and an optical switch that receives the return N+1 reflection pulse train from the N FBG sensors and one reference Fresnel reflector.

A system and method for simultaneously addressing multiple parallel distributed fiber optic sensors using a single interrogation instrument is disclosed. One or more of the fiber optic sensors are provided with a non-reflective delay element to prevent an overlap in time between backscatter returns from the distributed fiber optic sensors, thereby allowing the backscatter returns from each sensor to be distinguished based on round-trip transit time.