公开(公告)号：JPH11110673A

公开(公告)日：1999-04-23

申请号：JP21462198

申请日：1998-07-29

Applicant: LITTON SYSTEMS INC

Inventor： FREDERICK DONALD A ,  HALL DAVID B

IPC: H04B10/00 ,  G01L11/02 ,  G08C15/00

Abstract: PROBLEM TO BE SOLVED: To provide an optical pressure sensor having high accuracy and not requiring a wide area and also not being influenced by a loss accompanying the transmission of an optical signal, by using a contactless pressure sensor which is not electrical. SOLUTION: Plural optical couplers are connected to an optical transmission cable 16 with intervals placed and a partial signal is taken out form a pulse signal at the connection place. When a pulse optical signal transmits along the cable 16 and enters an array of an optical pressure sensor 22, plural couplers are respectively provided with an optical splitter, the sensor 22 and non pressure sensitive reflector 26, and non overlap signal pairs 30a to 30c are returned to the cable 16. The signal pairs 30a to 30c are inputted to a processor, and an intensity ratio of a pressure presentation signal 24 and a reference signal 28 which are included in the pairs 30a to 30c till here respectively is calculated. With this, because noise and loss can be compensated by using the signal 28, it is possible to acquire accurate pressure measurement value regardless of the position of the pressure sensor.

公开(公告)号：JP2000241239A

公开(公告)日：2000-09-08

申请号：JP21681298

申请日：1998-07-31

Applicant: LITTON SYSTEMS INC

Inventor： FREDERICK DONALD A ,  BELL STEVEN G

IPC: G01B9/00 ,  G01H9/00 ,  H01S3/06 ,  H01S3/07

Abstract: PROBLEM TO BE SOLVED: To provide a fiber sensor system capable of high resolution measurement of frequency change. SOLUTION: An end injection fiber laser outputting a plurality of laser modes is installed. An optical fiber 14 transferring a laser mode is connected with an active fiber sensor 16. The optical fiber 14 transfers a multiple laser mode to an optical amplifier fiber 22, An optical amplifier fiber 22 amplifies a laser mode signal. The amplified laser mode signal is sent to a phase modulator 34 connected with the optical fiber. An output from the phase modulator is sent to receiving interferometer 36, which has a specified pass in balance, and analyzes the respective frequency changes of the laser mode signal. A demodulation part 46 is connected with the interferometer 36, receives the output of the interferometer and demodulates the output.

公开(公告)号：JP2000065633A

公开(公告)日：2000-03-03

申请号：JP24781599

申请日：1999-07-30

Applicant: LITTON SYSTEMS INC

Inventor： HALL DAVID B ,  FREDERICK DONALD A ,  FERSHT SAMUEL N

IPC: G01B9/02 ,  G01H9/00 ,  G01V1/16 ,  G01V1/22

Abstract: PROBLEM TO BE SOLVED: To provide an optical waveguide vibration sensor system with improved maximum frequency displacement when configuring frequency modulation. SOLUTION: An optical waveguide pipe 28 formed in an integrated optical substrate 30 is included in the light path of a light interferometer 51, a light signal source 12 is provided so that it gives a light signal to the light interferometer 51, a channel waveguide phase modulator 38 is formed on the substrate 30, the light signal guided by the optical waveguide pipe 28 can be subjected to phase modulation, a signal from a diophone 50 for generating an electrical signal according to mechanical vibration is inputted to the phase modulator 38, the diophone 50 is connected to the channel waveguide phase modulator 38, the phase of the light signal guided by the optical waveguide pipe 28 is modulated by an electrical signal, an interference pattern that is outputted from the light interferometer 51 indicates the amplitude of mechanical vibration, and at least one optical fiber 24 is included in the light interferometer 51 for giving mismatching between the optical path lengths of the interferometer.

公开(公告)号：JPH1082692A

公开(公告)日：1998-03-31

申请号：JP15338697

申请日：1997-06-11

Applicant: LITTON SYSTEMS INC

Inventor： FREDERICK DONALD A ,  GOLDMAN ROBERT P ,  MAAS STEVEN J ,  MANSELL JOHN E

IPC: G01H9/00

Abstract: PROBLEM TO BE SOLVED: To provide an optical fiber hydrophone capable of averaging effects of a local noise source in a wide region and of being deployed in a portion around a sharp bend section. SOLUTION: An optical hydrophone 30 is constituted as a single interferometer 60 having a plurality of interferometer regions formed of a pair of optical fibers. Inner and outer coils each constituted of the pair of optical fibers are preferably provided as a coaxial pair and form a plurality of sensor regions. A spacer is constituted so as to guide the inner and outer optical fibers between the continuous sensor regions. The change of a physical parameter between sensor regions does not make a phase difference between optical signals guided by both of the fibers. The inner and outer optical coils are preferably exposed to the parameter so that the change of the parameter in each of sensor regions make change of the inverted phase to take place between optical signals in the outer coil and corresponding inner coil.

公开(公告)号：JPH1030955A

公开(公告)日：1998-02-03

申请号：JP4908497

申请日：1997-03-04

Applicant: LITTON SYSTEMS INC

Inventor： FREDERICK DONALD A ,  CAPPI JOHN F

IPC: G01B9/02 ,  G01H9/00 ,  G01V1/18 ,  G02B6/36 ,  H04B13/00 ,  H04R1/44 ,  H04R23/00

Abstract: PROBLEM TO BE SOLVED: To achieve the cost reduction of a hydrophone device, the simplification of part designs and reliability by forming a sensing arm as a coil, and incorporating an optical fiber having a certain length, which is arranged so that the change in optical-path length is experienced when an optical-fiber hydrophone is exposed to a sound field. SOLUTION: A reference arm 26 of an optical-fiber interferometer undergoes direct wet winding on a rod 32 formed of rigid material such as metal. Then, the elastic layer comprising potting material 40 and material such as urethane is formed on the reference arm 26. Then, a sensing arm 24 is wound on the elastic layer and covered with an elastic layer 44. In this way, a mandrel 30, to which the sensing arm 24 and the reference arm 26 are attached, is stable because the length of the reference arm 26 is wound on the rigid rod 32 when the mandrel is immersed in water and affected by a sound field. The change in sound field causes the change in length of the sensing arm 24, changes the optical-path length of the sensing arm 24 and generates the optical signal, which is processed so as to measure the change in intensity of the sound field.

公开(公告)号：WO0210691A3

公开(公告)日：2002-04-11

申请号：PCT/US0117135

申请日：2001-05-24

Applicant: LITTON SYSTEMS INC

Inventor： ARAB-SADEGHABADI AKBAR ,  FREDERICK DONALD A ,  CARLSON KURT R ,  CHERBETTCHIAN AGOP H

IPC: G01D11/24 ,  G02B6/42 ,  G02B6/44

CPC classification number: G01D11/245 ,  G02B6/4248 ,  G02B6/4428

Abstract: A pressure vessel capable of withstanding elevated hydrostatic pressures, and elevated temperature comprises a tubular cylindrical casing capable of withstanding extreme hydrostatic pressures having an internal cavity and a first and second opening at each end permitting access to said internal cavity. The internal cavity is divided into a first and second cylindrical plug region extending inward from the first and second opening and a hollow interior region. An optical component is in the hollow interior having at least a plurality of optical fiber pigtails extending from said optical component. A first and second cylindrical plug is force fit into first and second plug regions. At least one plug has a through-hole for receiving and passing at least some of the optical fiber pigtails to a position outside of the pressure vessel. At least one plug has a ceramic adhesive plug formed in a necked-down through-hole by inserting adhesive into the through-hole and filling substantially all of the void space within the through-hole not occupied by the optical fiber pigtails. The adhesive is allowed to encapsulate the leads or optical fibers passing through the through-hole to seal the opening. The plug has a channel machined into its outer circumference to receive an O-ring, the O-ring providing an additional seal between the plug and the tubular casing. A cap is formed to cover over and beyond the outer surface of the plug using a polymer adhesive.

Abstract translation: 能够承受升高的静水压力和升高的温度的压力容器包括能够耐受具有内部空腔的极端静水压力的管状圆柱形壳体，并且在每个端部处允许进入所述内部空腔的第一和第二开口。 内腔被分为从第一和第二开口向内延伸的第一和第二圆柱塞塞区域和中空的内部区域。 光学部件在中空内部具有至少多个从所述光学部件延伸的光纤尾纤。 第一和第二圆柱塞强制配合到第一和第二插塞区域中。 至少一个插头具有通孔，用于接收并将至少一些光纤尾纤传送到压力容器外部的位置。 至少一个插头具有通过将粘合剂插入通孔中而形成在颈缩通孔中的陶瓷粘合塞，并且基本上填充未被光纤尾纤占据的通孔内的所有空隙空间。 允许粘合剂封装通过通孔的引线或光纤以密封开口。 塞子具有加工成其外圆周的通道以容纳O形环，O形环在塞子和管状壳体之间提供额外的密封。 使用聚合物粘合剂形成盖以覆盖和超出塞子的外表面。

公开(公告)号：EP0814326A2

公开(公告)日：1997-12-29

申请号：EP97303752

申请日：1997-06-03

Applicant: LITTON SYSTEMS INC

Inventor： FREDERICK DONALD A ,  GOLDMAN ROBERT P ,  MAAS STEVEN J ,  MANSELL JOHN E

IPC: G01H9/00

CPC classification number: G01H9/004

Abstract: A fiber optic hydrophone (30) is formed as a single interferometer having widely separated interferometer segments (32-35) formed in each of a pair of optical fibers (56-70). The interferometer segments (32-35) are designed to allow averaging of the effects of local noise sources over a broad area in order to increase the acoustic signal-to-noise ratio. The interferometer segments (32-35) also allow deployment of the hydrophone around sharp bends. A first optical fiber (56) is formed into a plurality of spatially separated outer coils (58,90,94). A second optical fiber (70) is formed into a plurality of inner coils (72,92,96) corresponding to the outer coils. The inner (50) and outer coils (72) are preferably arranged in concentric pairs to form a plurality of sensor segments (32-35). A plurality of spacers (40-42) is arranged such that a spacer is between successive sensor segments. The spacers (40-42) are formed to guide the outer (56) and inner (70) optical fibers between successive sensor segments (32-35) such that changes in the physical parameter between the sensor segments (32-35) produce no phase difference between optical signals guided by the outer (56) and inner (70) fibers. The outer (58) and inner coils (70) are preferably arranged for exposure to the parameter such that changes in the parameter at each sensor segment produce opposite phase changes between the optical signals in the outer coils and the corresponding outer coil.

Abstract translation: 光纤水听器（30）形成为具有在一对光纤（56-70）中的每一个中形成的具有广泛分离的干涉仪段（32-35）的单个干涉仪。 干涉仪段（32-35）被设计成允许对广泛区域的局部噪声源的影响进行平均，以增加声信噪比。 干涉仪段（32-35）还允许在锋利的弯曲处部署水听器。 第一光纤（56）形成为多个空间分离的外部线圈（58,90,94）。 第二光纤（70）形成为对应于外部线圈的多个内部线圈（72,92,96）。 内部（50）和外部线圈（72）优选地以同心对布置以形成多个传感器段（32-35）。 多个间隔件（40-42）被布置成使得间隔件在连续的传感器段之间。 间隔件（40-42）形成为在连续传感器段（32-35）之间引导外（56）和内（70）光纤，使得传感器段（32-35）之间的物理参数的变化不产生 由外（56）和内（70）纤维引导的光信号之间的相位差。 外部（58）和内部线圈（70）优选地布置成暴露于参数，使得每个传感器段处的参数的变化在外部线圈和对应的外部线圈中的光学信号之间产生相反的相位变化。

公开(公告)号：EP0876582A4

公开(公告)日：2001-01-31

申请号：EP97949460

申请日：1997-11-14

Applicant: LITTON SYSTEMS INC

Inventor： FERSHT SAMUEL N ,  FREDERICK DONALD A

IPC: G01L1/24 ,  G01B9/02 ,  G01D5/353 ,  G01J9/02 ,  G01K11/12

CPC classification number: G01D5/35383

Abstract: The invention is a method and apparatus for determining the phase difference of light waves (31) after propagating through each of one or more two-path pairs, a two-path pair being two optical transmission paths connecting a common entry point (25) to a common exit point (29). Coherent light pulses (27) of predetermined duration are fed into the entry point (25) of each two-path pair in a group of two-path pairs at predetermined time intervals, the pulse duration being subdivided into a plurality of predetermined time segments. The phase difference for each two-path pair is determined from amplitude values of the electrical signal.

公开(公告)号：NO322785B1

公开(公告)日：2006-12-11

申请号：NO971036

申请日：1997-03-06

Applicant: LITTON SYSTEMS INC

Inventor： FREDERICK DONALD A ,  CAPPI JOHN F

IPC: G01B9/02 ,  G01H3/00 ,  G01H9/00 ,  G01V1/18 ,  G02B6/36 ,  H04B13/00 ,  H04R1/44 ,  H04R23/00

Abstract: A hydrophone has a fibre optic interferometer with a reference arm (26) formed by a length of optical fibre wound around a rigid mandrel (30) and with constant optical path length, elastic material (42) over the arm, and a concentric sensing arm (24) with a length of optical fibre wound over the material in a coil so that optical path length changes when the hydrophone is exposed to an acoustic field. Optical output signals are passed to a processor to measure acoustic pressure. Preferably, the elastic material is preferably polyurethane, and the sensing arm is encased in further elastic material (44) and spaced from the reference arm. The mandrel is e.g. a solid rod of metal or other rigid material with end flanges, and the reference arm is potted.

公开(公告)号：DE69914981T2

公开(公告)日：2004-12-09

申请号：DE69914981

申请日：1999-07-28

Applicant: LITTON SYSTEMS INC

Inventor： HALL DAVID B ,  FREDERICK DONALD A ,  FERSHT SAMUEL N

IPC: G01B9/02 ,  G01H9/00 ,  G01V1/16 ,  G01V1/22