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1. 发明专利

JPS5651702A LIGHT ATTENUATOR 失效
公开(公告)号：JPS5651702A
公开(公告)日：1981-05-09
申请号：JP12832879
申请日：1979-10-04
申请人： NIPPON TELEGRAPH & TELEPHONE , FUJIKURA LTD
发明人： TOKUDA MASAMITSU , SUGAWARA YASUYUKI
IPC分类号： G02B6/00 , G02B6/02 , G02B6/26 , G02B26/02
摘要： PURPOSE:To prevent the light attenuator from having directivity by axially aligning and joining the two optical fibers of which the distribution curves of the specific refractive index differences of the cores drawn by taking the specific refractive index differences as ordinate and the distance from the center as abscissa are under predetermined conditions. CONSTITUTION:The two optical fibers of which the distribution curves of the specific refractive index differences of the cores drawn with same sctle by taking the specific refractive index differences as of ordinate and the distance from the center as abscissa are in the relation satisfying the following two formulas are axially aligned and joined. The first relation should be such that when the distance (r) from the center is taken as abscissa and the specific refractive index difference DELTAn is expressed as the function of (r) as ordinate, the formula I intersects at least at one or more points within the range of 0

2. 发明专利

JPS59228144A MEASUREMENT OF OPTICAL FIBER 失效
公开(公告)号：JPS59228144A
公开(公告)日：1984-12-21
申请号：JP10322383
申请日：1983-06-09
申请人： FUJIKURA LTD , NIPPON TELEGRAPH & TELEPHONE , FURUKAWA ELECTRIC CO LTD , SUMITOMO ELECTRIC INDUSTRIES
发明人： SUGAWARA YASUYUKI , TOKUDA MASAMITSU , YAMASHITA KATSUYA , HIGASHIMOTO MASAKAZU , SUZUKI SHIYUUZOU
IPC分类号： G01M11/02 , G01M11/00 , G02B6/00 , G02B5/14
摘要： PURPOSE:To make it possible to precisely measure the base band characteristic without any influence caused by disturbance such as a modal noise by employing an optical signal luminance-modulated by a measurement signal capable of frequency sweep and a reference signal of a low frequency signal. CONSTITUTION:A signal of frequency f1 transmitted from an oscillator 11 capable of frequency sweep and a signal of frequency f2 transmitted from an oscillator 12 whose oscillation frequency is fixed are mixed together in a mixer 13. The thus mixed signals are transmitted to a bias circuit 2 where they luminance- modulate an optical signal emitted from a semiconductor laser 3. The optical signal is made incident on one end of an optical fiber 4 to be measured. The optical signal emerging from the other end thereof is converted into an electric signal by means of a light-receiving element 5. This signal is inputted through an amplifier 6 to a branching filter 14 where the components of frequency f1 and frequency f2 are taken out. The components are respectively demodulated by selective level meters 15 and 16. Thereafter, an amplitude ratio of the thus demodulated signal is obtained by virtue of a ratio meter 17 and is then transmitted to an indicator 8. With this process, the disturbant elements are offset, whereby the precise base band characteristic can be measured.

3. 发明专利

JPS55159134A MEASURING METHOD OF CONNECTION LOSS IN OPTICAL FIBER 失效
公开(公告)号：JPS55159134A
公开(公告)日：1980-12-11
申请号：JP6776179
申请日：1979-05-31
申请人： NIPPON TELEGRAPH & TELEPHONE , FUJIKURA LTD
发明人： TOKUDA MASAMITSU , WATANABE ATOU , ARAI TAKATOSHI , OOSATO KAZUKUNI , WATANABE NOBUHIKO
IPC分类号： G01M11/02 , G01M11/00
摘要： PURPOSE:To enable measurement readily and surely by radiating light of a fixed level to the connection point of optical cables, detecting this at the terminal part of the optical cables and detecting the magnitude of the quantity of said light. CONSTITUTION:A light source 14 is driven by a control circuit 18 to radiate its scattered light to the connection point X of optical fibers 8, 9 by way of a diffuser 13. On the other hand, a photodetector 22 such as photoelectric transducer is installed to the output end of the optical fiber 9 and a display device 21 is connected thereto by way of an amplifier 18 or the like. In case the end faces of the respective cores 10, 11 of the optical fibers 8, 9 are perfectly exially aligned and fusion-bonded, the quantity of the scattered light entering the inside of the cores 10, 11 is small but if there is any misalignment or the like, it enters there much and is detected by the photodetector 22. The electric signal level obtained by the photodetector 22 is compared of its maximum value with a reference level signal, is operated and is displayed as a connection loss value in a display device 21. In this way, the measurement may be done readily and surely simple by setting the measuring devices in two places.

4. 发明专利

JPS5569114A DECREASING METHOD FOR CONNECTION LOSS OF OPTICAL FIBER CABLE 失效
公开(公告)号：JPS5569114A
公开(公告)日：1980-05-24
申请号：JP14372378
申请日：1978-11-21
申请人： NIPPON TELEGRAPH & TELEPHONE , FUJIKURA LTD
发明人： TOKUDA MASAMITSU , UCHIDA NAOYA , ISHIHARA HIROSHI , SUGAWARA YASUYUKI , YAMADA TAKESHI , TANAKA MASAO
IPC分类号： G02B6/26 , G02B6/44
摘要： PURPOSE:To reduce the coupling losses owing to construction parameter differences by containing the optical fibers of the same parameter structure within the same groups of optical fiber cables and connecting the optical fibers within the same group with each other at the cable connecting. CONSTITUTION:Optical fibers 10 are divided to regions 11 thru 14 varying with construction parameters such as core diameter, refractive index difference, outside shape, ellipse, eccentricity and refractive index distribution. If the optical fibers of each of the regions 11-14 are trisected to the same groups 21-24 of the optical fiber cables 20A-20C and the optical fibers in the same groups 21-24 are connected with each other at the connecting of the cables 20A-20C, then the optical fibers of the same construction parameters are connected and the coupling looses owing to the differences in the construction parameters decrease.

5. 发明专利

JPS5875110A OPTICAL BRANCHING DEIVCE AND MEASURING METHOD USING SAID OPTICAL BRANCHING DEVICE 失效
公开(公告)号：JPS5875110A
公开(公告)日：1983-05-06
申请号：JP17359881
申请日：1981-10-28
申请人： NIPPON TELEGRAPH & TELEPHONE , FUJIKURA LTD
发明人： TOKUDA MASAMITSU , YAMAUCHI RIYOUZOU , WATANABE KOU , CHIGIRA SADAO
IPC分类号： G01M11/00 , G02B6/28
摘要： PURPOSE:To obtain an optical branching device of a low loss, which is applicable to a loop-like transmission line without a problem, by constituting so that an end face of 2 optical fibers is cut at a prescribed angle against the center axis, and a half-mirror is directly formed on one end face and is junctioned with the other end face. CONSTITUTION:As for optical fibers 51, 52, its end face is cut at an angle of about 45 deg. against the ceter axis, and is polished. Subsequently, on the end face of the optical fiber 51, a half-mirror 53 consisting of a metallic film and a dielectric layer and having optional reflection and transmission characteristics is formed, and the end face of the other optical fibers 52 is butted to this half- mirror 53 so that the optical axes coincide and is stuck by an adhesive. An insertion loss to the optical fiber 52 from the optical fiber 51 becomes the same extent as that which has connected a regular optical fiber, except a loss of a portion which has been made to branch by reflection of the half-mirror 53, and when this optical branching device is applied to a loop-like optical transmission line, a stable system of a low loss can be constituted.

6. 发明专利

JPS56115935A MANUFACTURE OF DUMMY FIBER FOR MEASUREMENT 失效
公开(公告)号：JPS56115935A
公开(公告)日：1981-09-11
申请号：JP1959880
申请日：1980-02-19
申请人： NIPPON TELEGRAPH & TELEPHONE , FUJIKURA LTD
发明人： TOKUDA MASAMITSU , TANAKA MASAO , YANAGI MINORU , ANDOU OSAMU , SUGAWARA YASUYUKI
IPC分类号： G01M11/00 , G01N1/28 , G01N3/00 , G01N3/08 , G02B6/00 , G02B6/02
摘要： PURPOSE:To manufacture the dummy fiber for measurement surely and efficiently by winding the core wire of an optical fiber round a bobbin with appropriate tension. CONSTITUTION:A split groove 12 is proided in the cylindrical bobbin 11 so that the diameter of the bobbin 11 can be extended and contracted. When screws 13 and 14 are revolved to the right, they press the end surface of the split groove 12 to extend the diameter, while when they are revolved to the left the diameter is contracted since the bobbin 11 is to return to its original state with the elasticity thereof. The core wire of the optical fiber is wound round the bobbin 11 with appropriate tension and later the screws 13 and 14 are revolved to the right or left, whereby the diameter is extended or contracted. Thus, the tension of the core wire of the optical fiber is controlled so as for the fiber to have necessary characteristics as the dummy fiber.

7. 发明专利

JPH03233370A METHOD AND DEVICE FOR MEASURING DISTRIBUTION OF DISTURBING ELECTROMAGNETIC WAVE 失效
公开(公告)号：JPH03233370A
公开(公告)日：1991-10-17
申请号：JP2830790
申请日：1990-02-09
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： MURAKAWA KAZUO , KUWABARA NOBUO , AMAMIYA FUJIO , TOKUDA MASAMITSU
IPC分类号： G01R29/08
摘要： PURPOSE:To attain an accurate measurement for distribution of a disturbing electromagnetic wave with reproducibility and less error independent of operator's skillfullness by measuring electromagnetic field components leaking from an object to be measured through the holes bored on a conductive plate, with an electromagnetic field sensor. CONSTITUTION:Current induced on the conductive plate 1 by the disturbing electromagnetic wave from a device 3 to be measured and the current become and equivalent current emitting source to emit the electromagnetic wave. At this time, the electromagnetic field leaked through the holes 2 bored on the conductive plate 1 is proportional to the intensity of incoming electromagnetic field, therefore, the distribution of electromagnetic field can be measured two- dimentionally by means of measuring the intensity with the electromagnetic field sensor 5 and repeating the measurement by moving the electromagnetic field sensor 5 two-dimentionally with a sensor driving system 7. As the result, the distribution of disturbing electromagnetic wave can be obtained. By this procedure, the accurate measurement for distribution of disturbing electromagnetic wave is made possible with reproducibility and less error.

8. 发明专利

JPH034856B2 失效
公开(公告)号：JPH034856B2
公开(公告)日：1991-01-24
申请号：JP16805281
申请日：1981-10-21
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： NAKAZAWA MASATAKA , TOKUDA MASAMITSU
IPC分类号： G01M11/00 , G01M11/02 , G02B6/00

9. 发明专利

JPH02275370A ELECTRIC FIELD ANTENNA USING CRYSTAL HAVING ELECTROOPTIC EFFECT 失效
公开(公告)号：JPH02275370A
公开(公告)日：1990-11-09
申请号：JP9526189
申请日：1989-04-17
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： KUWABARA NOBUO , AMAMIYA FUJIO , TOKUDA MASAMITSU
IPC分类号： G01R29/08
摘要： PURPOSE:To achieve a higher stability in conversion loss of an antenna by a method wherein a photoelectric power emitted from a light modulator is detected and an output level of a photo detector is corrected by a correction means according to a level thereof to eliminate dependence of the conversion loss of the antenna on the level of an outgoing light of a light source. CONSTITUTION:A photoelectric power P1 to be emitted from a light source 1 is set with a directional coupler 15 set on the side of the light source 1 of a system in which an antenna for detecting intensity of an electric field is inserted to measure an intensity of an electric field accurately without disturbing an ambient electromagnetic distribution and a photoelectric power P2 emitted from a receiver 13 having a light modulator is set with a directional coupler 15 set on the side of a photo detector 11. When a signal is small sufficiently with respect to an amplitude of light wave, a ratio P2/P1 of powers P1 and P2 is determined by a specified computation, thereby enabling a measurement compensated for a change in photoelectric power of the light source 1 and a change in intrinsic phase value of a crystal.

10. 发明专利

JPS6238683B2 失效
公开(公告)号：JPS6238683B2
公开(公告)日：1987-08-19
申请号：JP17070782
申请日：1982-09-29
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： YAMASHITA KATSUYA , HATANO YOSHINORI , TOKUDA MASAMITSU
IPC分类号： G01B11/00 , B25B7/00 , G02B6/00 , G02B6/02 , G02B6/28 , G02B6/42 , H04B10/07 , H04B10/079

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