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1. 发明专利

JP2003149478A OPTICAL WAVEGUIDE CIRCUIT, OPTICAL WAVEGUIDE MODULE HAVING THE OPTICAL WAVEGUIDE CIRCUIT AND METHOD FOR MANUFACTURING OPTICAL WAVEGUIDE CIRCUIT 审中-公开
公开(公告)号：JP2003149478A
公开(公告)日：2003-05-21
申请号：JP2002278000
申请日：2002-09-24
申请人： NIPPON TELEGRAPH & TELEPHONE , NTT ELECTRONICS CORP
发明人： INOUE YASUYUKI , KANEKO AKEMASA , TAKAHASHI HIROSHI , HANAWA FUMIAKI , HATTORI KUNINORI , YOKOYAMA KENJI , SUZUKI SENTA , SUMITA MAKOTO , OKAMOTO KATSUNARI , ISHII MOTOCHIKA , YAMADA HIROAKI , YOSHIDA TAKUJI , ARISHIMA KOICHI , EBISAWA FUMIHIRO , NAKAHARA MOTOHIRO
IPC分类号： G02B6/12 , G02B6/13
摘要： PROBLEM TO BE SOLVED: To provide an optical waveguide circuit capable of reducing temperature dependence. SOLUTION: In a light waveguide circuit including a plurality of waveguides having different length, a material (10) having a temperature coefficient of a refractive index including a symbol different from that of a temperature coefficient of an effective refractive index of the waveguide (4) is charged in a groove (12) formed by removing an upper clad and a core from the waveguide (4), or a groove (12) formed by removing the upper clad, the core and a lower clad from the waveguide 4. A difference in length of the removed portions between adjacent waveguides is proportional to a difference in length of the waveguides which were not removed and remained.

2. 发明专利

JPH0961299A LOW COHERENCE REFLECTOMETER 失效
公开(公告)号：JPH0961299A
公开(公告)日：1997-03-07
申请号：JP21563695
申请日：1995-08-24
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： TAKADA KAZUMASA , YAMADA HIROAKI
IPC分类号： G01M11/02 , G01M11/00
摘要： PROBLEM TO BE SOLVED: To allow components caused by residual reflection to be removed and obtain a highly sensitive reflectometer by providing a modulation optic system in an optical delay circuit and also providing a wave detection system corresponding to the modulation in a signal processing system. SOLUTION: A phase modulator 21 whose refractive index periodically varies according to frequency (f) from a transmitter 22 is provided between a lens 13 and a reflecting mirror 15 of an optically variable delay circuit 7. Although a light beam 15 is subjected to phase modulation at a predetermined frequency f1 while it goes to and back from the modulator 21, residual reflection light may not be phase- modulated as it does not pass through the modulator 21. Therefore an interference signal between reference light reflected on the reflecting mirror 15 and back Rayleigh scattered light of a light waveguide 6 which has been phase-modulated at frequency (f) of a transmitter 12 includes a component which varies at frequency of f+f1 , but an interference component of residual reflection light and reflection light varies only at frequency (f). Accordingly, by setting wave detection frequency f+f1 in a signal processing system 11 and adjusting a wave detection band width so that the frequency (f) component may not be mixed, the output caused by residual reflection can be removed.

3. 发明专利

JPH08166511A TWO-INPUT TWO-OUTPUT OPTICAL BAND PASS FILTER AND LOW COHERENT LIGHT SOURCE 失效
公开(公告)号：JPH08166511A
公开(公告)日：1996-06-25
申请号：JP30497994
申请日：1994-12-08
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： TAKADA KAZUMASA , HORIGUCHI MASAHARU , YAMADA HIROAKI
IPC分类号： G02B26/00 , G02B5/28
摘要： PURPOSE: To vary the light quantities of plural inputted light beams while the central wavelengths of transmitting beams are made in coincidence using a single optical band-pass filter by making the beams cross at the same incident point and symmetric about the normal to the filter surface. CONSTITUTION: Light beams 44, 45 made to be parallel by means of collimators 42, 43 are made incident on a point '0' on the cross line between an interference filter 35 and a virtual plane 38 perpendicular to the surface 36 of the interference filter 35 including a rotary axis 37 when the rotation angle is zero. The light beams 44, 45 are included in the virtual plane 38 and, when the central wavelength of transmitting beams is changed by rotating the interference filter 35 about the rotary axis 37 provided in the surface of the interference filter 35, are made incident on a point '0' with the same incident angle ϕ while they are always symmetric about the normal of the front surface of the interference filter 35. Consequently, by using one optical band-pass filter, the two-input two-output optical band pass filter in which the transmitting central wavelengths of the respective light beams are always in coincidence and their light quantities are variable are realized.

4. 发明专利

JPH0618726A PRODUCTION OF CORE EXPANDING OPTICAL FIBER 失效
公开(公告)号：JPH0618726A
公开(公告)日：1994-01-28
申请号：JP17395592
申请日：1992-07-01
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： TAKEUCHI YOSHIAKI , YAMADA HIROAKI , HIRAYAMA MAMORU
IPC分类号： G02B6/02 , G02B6/10 , G02B6/14
摘要： PURPOSE:To provide the process for production of the core expanding optical fiber which is produced by an optical fiber to be used as a light transmission path and is used for connection between different optical fibers, connection between optical parts and the optical fiber, etc. CONSTITUTION:A small-sized electric oven 10 is used as a heating means and the optical fiber is heat treated by setting the max. temp. near the center of the oven 10 of the optical fiber at 1500 to 1700 deg.C and the temp. at both ends of the oven at

5. 发明专利

JPH11109155A TEMPERATURE INDEPENDENT WAVEGUIDE 失效
公开(公告)号：JPH11109155A
公开(公告)日：1999-04-23
申请号：JP27167697
申请日：1997-10-03
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： YOSHIDA TAKUJI , ARISHIMA KOICHI , YAMADA HIROAKI , OKAMOTO KATSUNARI
IPC分类号： G02B6/122 , G02B6/12
摘要： PROBLEM TO BE SOLVED: To realize an easy temperature independent waveguide with a relatively low cost and a safe structure which is independent from the environmental temperature. SOLUTION: Carbon fiber sheets 31, 32 having small thermal expansion coefficients are closely arranged on the surfaces of optical waveguides 13, 14, or the waveguide surfaces and the reverse side of a base 11, or the reverse side of the base, or the base itself is formed of a carbon fiber sheet. Since the contraction of the optical waveguides by a temperature change is minimized, following the carbon fiber sheet free from contraction, the temperature change of optical path length of the optical waveguides can be suppressed.

6. 发明专利

JPH05343786A 失效
公开(公告)号：JPH05343786A
公开(公告)日：1993-12-24
申请号：JP14729892
申请日：1992-06-08
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： KITAGAWA TAKESHI , YAMADA HIROAKI , HATTORI KUNINORI , OGUMA MANABU , SHUDO KEIZO , HORIGUCHI MASAHARU
IPC分类号： H01S3/06 , H01S3/1055 , H01S3/16
摘要： PURPOSE:To lower an oscillation threshold level and to increase a differential efficiency and an efficiency by constructing on a flat substrate a laser resonator which is constituted of an optical waveguide, to at least a part of which rare earth ions are added, and by providing an optical beam induced grating in at least a part of the optical waveguide. CONSTITUTION:Using an Er-doped quartz optical waveguide, an Er-doped optical waveguide-type laser having a grating is manufactured by two-beam interference exposure. In this laser, a quartz glass substrate 6, a lower clad layer formed of quartz glass 7, a rare-earth ion-implanted core 8, an upper clad layer formed of quartz glass 9, and an optical beam induced grating 10 are provided. In (A), the grating 10 is used for one reflecting mirror and a dielectric multilayer film mirror 11 deposited on an end face of an optical guide is used for the other reflecting mirror. In (B), an optical resonator is constructed, using the gratings 10 for reflecting mirrors on both ends. (C) is a distribution feedback- type optical resonator wherein the grating 10 is formed in the entire resonator.

7. 发明专利

JPH04260007A METHOD AND DEVICE FOR INCREASING MODE FIELD DIAMETER OF OPTICAL FIBER 失效
公开(公告)号：JPH04260007A
公开(公告)日：1992-09-16
申请号：JP2216191
申请日：1991-02-15
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： HANABUSA HIROAKI , YAMADA HIROAKI , NODA JUICHI
IPC分类号： G02B6/00 , G02B6/02 , G02B6/10 , G02B6/14 , G02B6/24 , G02B6/26 , G02B6/42
摘要： PURPOSE:To connect a quartz-based optical fiber with low loss or at low cost. CONSTITUTION:The optical fiber 12 constituted by adding a dopant to its core or clad has its jacket removed at the part where the mold field diameter is to be increased and is fixed on fixation bases 13a-13c while impressed with a tensile force and extended straight; and only an extremely short section of the jacket-removed part 12a is heated by a couple of microburners 18A and 18B of the same size without deforming the optical fiber. Consequently, the dopant added to the core or clad is thermally diffused to increase the mode field diameter.

8. 发明专利

JP2001004810A LIGHT ABSORBING FILM FOR OPTICAL COMMUNICATION, AND OPTICAL FIXING ATTENUATOR AND OPTICAL TERMINATOR USING THE SAME 失效
公开(公告)号：JP2001004810A
公开(公告)日：2001-01-12
申请号：JP17050799
申请日：1999-06-17
申请人： NIPPON TELEGRAPH & TELEPHONE , NTT ADVANCED TECH KK
发明人： SAWADA TAKASHI , SASAKI SHIGEKUNI , YAMADA TAKASHI , KATO KUNIHARU , YAMADA HIROAKI , KATADA KUMIKO , YAMAMOTO FUMIO
IPC分类号： G02B6/00 , G02B5/00 , G02B6/02 , G02B6/10 , G02B6/122
摘要： PROBLEM TO BE SOLVED: To economically solve the difference in the transmission loss differing for every waveguide of a waveguide type optical device with a small sized and easy to handle device by using a polymer film having carbon black dispersed therein as an optical communication light absorptive film. SOLUTION: This optical communication light absorptive film has a polymer film having carbon black dispersed therein. Although various carbon blacks are available, the fine particle size of the carbon black is preferably less than 1 μm in order to prevent the abnormal scattering of light and provide a uniform loss in any position of the film surface because a light having a wavelength of about 1 μm is used in the application to a waveguide type optical device. Such a carbon black is uniformly dispersed to a polymer film, for example, polyimide, whereby a loss of several dB to several tens of dB can be controlled with a thickness of several tens μm. The loss can be controlled by changing the blending quantity of carbon black. For example, the loss of a 20 μm-thick light absorptive film with 0.5 wt.% of carbon black dispersed therein is about 2.5 dB.

9. 发明专利

JPH09264809A METHOD AND DEVICE FOR MEASURING REFLECTION 失效
公开(公告)号：JPH09264809A
公开(公告)日：1997-10-07
申请号：JP7753196
申请日：1996-03-29
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： TAKADA KAZUMASA , YAMADA HIROAKI
IPC分类号： G01M11/00 , G01M11/02
摘要： PROBLEM TO BE SOLVED: To shorten calculation time by providing an auxiliary interferometer in a reflectometer body, and performing phase detection with the beat signal generated at the auxiliary interferometer used as a reference signal, so that data is reduced by one order or more. SOLUTION: With interference beat signsal Vr (X) from an auxiliary interferometer as a reference signal, lock-in detection is performed with a signal V(X), and Vcos (X) and Vsin (X) are measured. Then, with (i) as an imaginary number unit, Vcos (X)+Vsin (X) is calculated, and its Fourier conversion H(η) is calculated. With the use of window function W(η) of the real number which is maximum when n=0 and decreases at n>0 and a constant ηn , a real number part G(X) of inverse Fourier conversion of W(η-ηn ) H(η) is obtained. Then, ηn is changed within a range of ηwherein h( η)=g(σ0 +η) takes an finite value, and at the same time, the width of W(η-ηn ) is set significantly narrower than that of g(σ0 +η), so that a mean value of |2Cn G(X)| is obtained. Where, Cn is expressed as an equation.

10. 发明专利

JPH07243939A LOW-COHERENT REFLECTOMETER AND REFLECTION MEASURING METHOD 失效
公开(公告)号：JPH07243939A
公开(公告)日：1995-09-19
申请号：JP3455394
申请日：1994-03-04
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： TAKADA KAZUMASA , HORIGUCHI MASAHARU , YAMADA HIROAKI
IPC分类号： G01M11/00 , G01M11/02
摘要： PURPOSE:To concurrently measure the distribution of multiple reflection by feeding one branch light branched from the outgoing light into light guide paths to be tested, synthesizing the generated reflected light with the other branch light, and detecting the intensity of the synthesized light. CONSTITUTION:A photo-coupler 12 used as an optical means branches the outgoing light of a light source 1, one branch light is fed to light guide paths 26-30 to be tested, and the reflected light generated in the light guide paths 26-30 is synthesized with the other branch light. A light detector 10 used as a light detecting means detects the intensity of the light synthesized by the photo- coupler 12. Multiple light guide paths 26-30 are connected to ports 15-19 respectively. Modulators 21-25 are installed, and the modulators 21-25 are driven at different frequencies. The frequency constituents corresponding to the driving frequencies in the interference constituents are detected. The reflection distribution is obtained based on the constituents. Level meters 31-35 are adjusted to measure the signal levels of various frequencies at the band width of 1Hz.

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