A fibre-optic measurement system equipped with a controlled light generation system (1) and a receiving system (2) connected via an optical path which comprises a directional device (4) and which, in addition, has a processing unit (9) for controlling the light generation system (1) and for receiving and processing the signal from the receiving system (2), according to the invention, it is characterized by the fact that it has a selective mode device (5) and is adapted to be connected to a fibre-optic telecommunications network by a selective mode device (5) and the processing unit (9) is adapted to implement the OFDR and/or COTDR measurement technique for measuring changes in the optical distance and processing them into one or more parameters. Moreover, the object of the invention is also the method of adaptation of a telecommunications network into a sensor network and a fibre-optic measurement and communication system.

In some examples, fiber optic link intermittent fault detection and localization may include determining, for a fiber optic link that is to be analyzed, at least one section corresponding to the fiber optic link, at least one detection threshold corresponding to the at least one section, and a reference trace for the fiber optic link. A real-time trace may be acquired for the fiber optic link, and a comparison trace may be generated based on analysis of the reference trace and the real-time trace. Based on analysis of the at least one section to determine whether at least one section level parameter determined from the comparison trace exceeds the at least one detection threshold, an event associated with the fiber optic link may be identified.

A system and method for performing an in-service optical time domain reflectometry test, an in-service insertion loss test, and an in-service optical frequency domain reflectometry test using a same wavelength as the network communications for point-to-point or point-to-multipoint optical fiber networks while maintaining continuity of network communications are disclosed.

A process including the following steps: injecting in an optical fiber a first optical pump at a first optical frequency that evolves in time or not, and a second optical pump at a second optical frequency that evolves in time or not, the first optical frequency and the second optical frequency being different at each given time; a first detection of a first Rayleigh backscattered signal at the first optical frequency from the optical fiber, a second detection, separated from the first detection, of a second Rayleigh backscattered signal at the second optical frequency from the optical fiber; and analyzing the detected first Rayleigh backscattered signal and the detected second Rayleigh backscattered signal.

In some examples, fiber optic link intermittent fault detection and localization may include determining, for a fiber optic link that is to be analyzed, at least one section corresponding to the fiber optic link, at least one detection threshold corresponding to the at least one section, and a reference trace for the fiber optic link. A real-time trace may be acquired for the fiber optic link, and a comparison trace may be generated based on analysis of the reference trace and the real-time trace. Based on analysis of the at least one section to determine whether at least one comparison trace section level indicator determined from the comparison trace exceeds the at least one detection threshold, an event associated with the fiber optic link may be identified.

The application discloses a light scattering parameter measurement system and its measurement method. Dual-frequency scattering interference technology is adopted to obtain distributed measurement of Rayleigh scattering parameters in an optical fiber. The Rayleigh scattering coefficient r and phase retardance θ are modulated on different components of the interference signal respectively by using the dual-frequency interference technology. The Rayleigh scattering coefficient r and phase retardance θ can be decoupled by simple filtering, to obtain separate measurements. A linear stretch is applied to the optical fiber under test, to add uniform phase change signals at all positions of the optical fiber under test. As a result, the term containing only Rayleigh scattering coefficient r can be extracted by low-pass filtering. The direct measurement of Rayleigh scattering parameters is of great significance to fundamental and application researches related to Rayleigh scattering of optical fiber.

The present disclosure provides a method and system for estimating the distance between an optical fiber end and a target. Treatments which use laser and optic fiber technology require high amounts of accuracy to ensure that the laser is aimed at the right target (stone, tissue, tumor etc.), to achieve the clinical objective of tissue ablation, coagulation, stone fragmentation, dusting and the like. Accordingly, it is important to know the distance between the target and end of the optical fiber (distal end) where the laser light is emitted, since the laser treatment parameters, such as energy, pulse width, laser power modulation, and/or repetition rate, are often determined based on the distance between the tip of the optical fiber to the target.

A multi-core fiber includes multiple optical cores, and for each different core of a set of different cores of the multiple optical cores, a total change in optical length is detected. The total change in optical length represents an accumulation of all changes in optical length for multiple segments of that different core up to a point on the multi-core fiber. A difference is determined between the total changes in optical length for cores of the set of different cores. A twist parameter and/or a bend angle associated with the multi-core fiber at the point on the multi-core fiber is/are determined based on the difference.

A multi-core fiber includes multiple optical cores, and for each different core of a set of different cores of the multiple optical cores, a total change in optical length is detected. The total change in optical length represents an accumulation of all changes in optical length for multiple segments of that different core up to a point on the multi-core fiber. A difference is determined between the total changes in optical length for cores of the set of different cores. A twist parameter and/or a bend angle associated with the multi-core fiber at the point on the multi-core fiber is/are determined based on the difference.

An improved technique for acoustic sensing involves, in one embodiment, launching into a medium, a plurality of groups of pulse-modulated electromagnetic-waves. The frequency of electromagnetic waves in a pulse within a group differs from the frequency of the electromagnetic waves in another pulse within the group. The energy scattered by the medium is detected and, in one embodiment, the beat signal may be used to determine a characteristic of the environment of the medium. For example, if the medium is a buried optical fiber into which light pulses have been launched in accordance with the invention, the presence of acoustic waves within the region of the buried fiber can be detected.