Abstract: An optical fiber sensing system according to the present disclosure includes: an optical fiber (11) configured to sense water pressure change caused by an event that has occurred in an observation region, the optical fiber being disposed in water; a reception unit (20) configured to receive a light signal from the optical fiber (11); and an identification unit (30) configured to detect distribution of water pressure and time fluctuation of water pressure in the observation region based on a pattern of the light signal, and to identify an event that has occurred in the observation region based on the detection result.

Abstract: A measurement system, a measurement device, and a measurement method being able to measure a flow speed for each position of an optical fiber are provided. According to one example embodiment, a measurement system includes: an object provided in a fluid, and generating a self-excited vibration by the fluid; an optical fiber provided in the fluid, and detecting the vibration; a light source outputting light P to the optical fiber; an acquisition unit acquiring backscattered light generated from the light P in the optical fiber and including a pattern indicating the vibration in a vibration position on the optical fiber to which the vibration of the fluid is transmitted; and a measurement unit measuring, from a pattern included in the backscattered light and indicating the vibration, a flow speed of the fluid in the vibration position.

Abstract: A slight movement of the ground is detected. A cable, which includes an optical fiber, is provided to have friction with the ground in such a way that the optical fiber is expanded and contracted in accordance with the movement of the ground. An optical output unit outputs a monitoring light to the optical fiber. A partial reflection unit is provided on a path of the optical fiber in the cable and partially reflects the monitoring light. An optical reception unit receives a reflection light reflected by the partial reflection unit. A calculation unit measures the length of the optical fiber to the partial reflection unit based on a round-trip propagation time of the reflection light that has been received and monitors its changes over time.

Abstract: An optical fiber cable for sound wave sensing that uses a straight optical fiber and is capable of suppressing directivity is provided. The optical fiber cable for sound wave sensing includes a cover part (10) that is capable of covering a straight cable core (11) and is provided with a sound wave refraction part (12) which refracts sound waves made incident roughly perpendicularly to a longitudinal direction of the cable core (11) and makes the sound waves be incident diagonally to the longitudinal direction of the cable core (11). The cover part (10) includes a gap filling part (23) which covers the sound wave refraction part (12).

Abstract: In order to avoid the phenomenon of communication being impeded and signals transmitted by the plurality of slave devices overlapping, a communication system according to the present invention has the first master device transmits a first pulsed light to the first transmission path and receives a return light of the first pulsed light from the second transmission path; each of the slave devices modulates the first pulsed light, and outputs the modulated first pulsed light as the return light of the first pulsed light; and the width of the first pulsed light is narrower than double the shortest distance from among the transmission distance between the slave device outputting the return light and the transmission distance between the first master device and the slave device outputting the return light.

Abstract: To suppress expansion of damage to a working-state cable due to work being continued without detecting breakage of the working-state cable when the breakage occurs, the working-state cable protection monitoring system is provided with: a working means that moves or installs a wire cable-shaped construction material including an optical fiber having at least one core; an interrogator that acquires environment information about each position of the construction material, sensed by the optical fiber; and an abnormal event detection means that, when the environment information acquired at each position of the construction material satisfies an abnormal pattern, detects an abnormal event at the position, where in the working means stops movement and installment of the wire cable-shaped construction material when the abnormal event has been detected.

Abstract: In order to facilitate fixed-point monitoring over a wide area and for a long time, this water area monitoring device comprises: a detection unit for information, such as water area intrusion, which detects, from sound data that is acquired by means of optical fibers installed in the water or the water bottom and is data pertaining to a sound or a vibration at the respective positions of the optical fibers, at least any one among sounds of water area intrusion or the like that indicate intrusion into a target water area or water area intrusion or the like, which is a prescribed behavior in the target water area, at a time at which sound data is acquired, and changes in sounds or vibrations not caused by the water area intrusion or the like; and an output unit which outputs information indicating the sound such as water area intrusion.

Abstract: In, for example, the overly vast ocean, it would be economically impossible to use common sensors to construct a sensor network for capturing a rare phenomenon. This invention addresses the problem of providing an unconfirmed sound extraction device, and the like, for facilitating the monitoring of sound caused by an infrequently occurring phenomenon. This unconfirmed sound extraction device comprises an unconfirmed sound extraction unit for extracting, from sound data that has been acquired using an optical fiber and is related to sound at various positions on the optical fiber, unconfirmed sound information representing unconfirmed sound data, which is of the sound data and is on a sound having a cause that cannot be estimated, at a sound data acquisition time and location, and an output unit for outputting the unconfirmed sound information.

Abstract: To observe sounds produced by aquatic organisms with less effort, this aquatic organism observation device is made to include an aquatic organism information detection unit for detecting, from sound data that has been acquired using an optical fiber installed in or at the bottom of water and is related to sound at various positions on the optical fiber, a sound emitted by an aquatic organism at a sound data acquisition time and location, and an output unit for outputting aquatic organism information.

Abstract: In order to facilitate the disposition of multiple noise measuring points in a distributed manner, this underwater noise monitoring device is provide with: a processing unit in which, by using data which was acquired using optical fibers installed underwater or on a bottom of water and which indicates noise or vibration at the position of each of the optical fibers, a statistical value of the amount of noise or vibration is derived at the time and the place when/where the data was acquired; and an output unit that outputs the statistical value.

Abstract: In order to provide a mechanism which predicts a risk of future failure occurrence, by using fiber optic sensing, this failure prediction system comprises: a sensing function unit which acquires the environmental information detected by the optical fiber; an event classification function unit which classifies, by type, events occurring at each position of the object indicated by the environmental information, on the basis of event classification conditions; and a failure occurrence risk calculation unit having, in advance, one or more failure models obtained by modeling a physical mechanism that leads to a malfunction in the object, wherein the failure occurrence risk calculation unit calculates a failure occurrence risk in each object by the mechanism, and outputs the accumulated result as a risk or availability.

Abstract: To facilitate the acquisition of environment information for a distant observation point, this environment information acquisition system is made to comprise a Fiber Bragg Grating (FBG) sensor that is placed on an optical path comprising optical fiber and has a grating pitch that changes according to surrounding environment information, a detection unit for detecting the phase variation of probe light that is transmitted via the optical fiber and reflected by the FBG sensor as return light, and an environment information calculation unit for calculating surrounding environment information for the FBG sensor from the phase variation.

Abstract: In order to provide a protection monitoring system that comprises a warning function to which it is not easy to become habituated, and that can call attention at the time when abnormal vibration is sensed even without a cable undergoing failure, the protection monitoring system according to an embodiment of the present invention comprises an optical fiber provided along a long infrastructure element installed in water or on a seabed, an interrogator for acquiring environment information at positions along the long infrastructure element using the optical fiber, an abnormal event detection means for detecting an abnormal event around the positions when the environment information acquired at the positions satisfies an abnormality pattern provided in advance, and a notification means for issuing a notice to a ship positioned in a prescribed range from a position in which the abnormal event is detected.

Abstract: A water pressure fluctuation measuring system detects a water pressure fluctuation. A cable, which includes an optical fiber, is provided on or in the ground of the seabed in such a way that the optical fiber is expanded and contracted according to the water pressure fluctuation. An optical output unit outputs monitoring light to the optical fiber. A partial reflection unit is provided on a path of the optical fiber in the cable and partially reflects the monitoring light. An optical reception unit receives reflection light reflected by the partial reflection unit. A calculation unit measures a length of the optical fiber to the partial reflection unit, based on a round-trip propagation time of the received reflection light, and monitors a change of the length over time.

Abstract: A processing device disposed inside a transmitter/receiver intended for use in optical fiber sensing using an optical fiber in order to enable restricting utilization of a prescribed range of acquired data, the processing device comprising: a mask unit which masks a prescribed range of acquired data, which is the data acquired by the transmitter/receiver through the optical fiber sensing; and an output unit which outputs post-masking data, which is the data that has undergone the aforementioned masking, to the outside of the transmitter/receiver, wherein the acquired data prior having the masking performed thereon for the prescribed range is not outputted to the outside.

Abstract: An optical fiber sensing range limiting device comprises: a blocking unit that, on the basis of a control signal and for a prescribed period, causes probe light that has been sent to an optical fiber used in optical fiber sensing and has returned from the optical fiber to be blocked from being transmitted to a light detection unit, or causes a detection signal that is detected with respect to the return light to be blocked from being transmitted to a downstream processing unit; and a control unit that outputs the control signal to the blocking unit. The prescribed period includes a period corresponding to the positional range for which acquisition of information from the detection signal is prohibited or for which it is undesirable to acquire the information.

Abstract: A measurement system, a measurement device, and a measurement method being able to measure a flow speed for each position of an optical fiber are provided. According to one example embodiment, a measurement system includes: an object provided in a fluid, and generating a self-excited vibration by the fluid; an optical fiber provided in the fluid, and detecting the vibration; a light source outputting light P to the optical fiber; an acquisition unit acquiring backscattered light generated from the light P in the optical fiber and including a pattern indicating the vibration in a vibration position on the optical fiber to which the vibration of the fluid is transmitted; and a measurement unit measuring, from a pattern included in the backscattered light and indicating the vibration, a flow speed of the fluid in the vibration position.

Abstract: According to the present example embodiment, the optical fiber sensing system is an optical fiber sensing system being acquired by adding a function of optical fiber sensing to a cable of an optical communication cable system. The optical communication cable system includes the cable including an optical fiber core wire that propagates an optical signal for communication, and a plurality of devices. A function of the optical fiber sensing is a function of, by an interrogator, sending probe light to an optical fiber core wire, detecting backscattered light of the probe light, and performing sensing on environmental information around the cable. The device includes an optical wiring line through which sensing light passes without passing through an optical amplifier.

Abstract: An acoustic sensor that uses an optical fiber and has a high directivity is provided. An acoustic sensor includes a sensing part and an interrogator. The sensing part has a sensing element composed of an optical fiber. The interrogator is connected to the sensing part, sends a pulse light P to the sensing part, and detects an acoustic wave sensed by the sensing part based on a reflected return light from the sensing part. The sensing element is composed of the optical fiber folded in such a way that it reciprocates a plurality of number of times along a directivity direction in which directional sensitivity is exhibited.

Abstract: To apply an optical amplification repeater device to optical fiber sensing to lengthen a sensing range, as well as to enable compatibility with an optical communication system a cable system that uses a cable for optical fiber communication and optical fiber sensing of an environment surrounding the cable, wherein: the optical fiber communication is bidirectional communication using optical fiber pairs which are pairs of the optical fiber; in an optical fiber, a first wavelength band and a second wavelength band are different from each other; an optical amplification unit included in the optical amplification repeater device includes a first amplifier and a second amplifier that amplify rays of light in mutually opposing directions; and each of the communication optical signal, the probe light, and the backscattering light is amplified by at least either the first amplifier or the second amplifier.