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31. 发明专利

JP2003262841A OPTICAL MODULATOR AND DESIGNING METHOD 审中-公开
公开(公告)号：JP2003262841A
公开(公告)日：2003-09-19
申请号：JP2002062095
申请日：2002-03-07
申请人： FUJITSU LTD
发明人： SUGIYAMA MASAKI , NAKAZAWA TADAO
IPC分类号： G02F1/035 , G02F1/03 , G02F1/225
摘要： PROBLEM TO BE SOLVED: To improve the speed and performance of an optical modulator by securing a modulation band and reducing driving voltage. SOLUTION: The optical modulator comprises: an optical waveguide 11 formed on a crystal substrate having an electro-optic effect; a signal electrode 12 formed in the neighborhood of the optical waveguide 11; and a ground electrode 13 formed on both sides of the signal electrode 12. The range of the characteristic impedance 20 of the signal electrode 12 is fixed so that the reflection of microwaves may be equal to or smaller than a fixed value. When the phases of light and the microwaves match with each other, 40 Gb/s or more optical modulation is performed with a gap of 50 μm or more between the signal electrode 12 and the ground electrode 13 and with 50 mm or more working length L of the signal electrode 12. COPYRIGHT: (C)2003,JPO

32. 发明专利

JP2001228451A MANUFACTURING METHOD OF ACOUSTOOPTICAL TUNABLE FILTER 失效
公开(公告)号：JP2001228451A
公开(公告)日：2001-08-24
申请号：JP2000040792
申请日：2000-02-18
申请人： FUJITSU LTD
发明人： SUGIYAMA MASAKI , NAKAZAWA TADAO , KIYONO MINORU
IPC分类号： G02F1/125 , G02F1/335
摘要： PROBLEM TO BE SOLVED: To obtain an acoustooptical tunable filter(AOTF) of good characteristics easily by the manufacturing method of the AOTF. SOLUTION: The manufacturing method of the AOTF includes a step for forming a waveguide structure 4 of light and a waveguide structure 6 of a surface acoustic wave on a substrate 2, and a step for re-forming the waveguide structure of the surface acoustic wave. The re-formed step includes a step for forming a thin film 24 near the waveguide structure of light and the waveguide structure of the surface acoustic wave, and a step for etching the thin film.

33. 发明专利

JPH03253815A OPTICAL WAVEGUIDE DEVICE 失效
公开(公告)号：JPH03253815A
公开(公告)日：1991-11-12
申请号：JP5202290
申请日：1990-03-02
申请人： FUJITSU LTD
发明人： KIYONO MINORU , MEGATA NAOYUKI , NAKAZAWA TADAO , KUBOTA YOSHINOBU , DOI MASAHARU
IPC分类号： G02B6/12 , G02F1/035 , G02F1/21 , G02F1/225
摘要： PURPOSE:To suppress and compensate a DC drift effectively by varying the distribution of an electric field, applied to and nearby an optical waveguide by a couple of a signal and a grounding driving electrode, greatly by the variation of the frequency of an electric signal. CONSTITUTION:The optical waveguide 2 is formed on the surface of an electrooptic crystal substrate 1 and the couple of driving electrodes 5 and 6 for a signal and for driving are formed on the optical waveguide 2. The distribution of the electric field applied to and nearby the optical waveguide 2 by the electrodes 5 and 6 is varied greatly by the variation of frequency of the electric signal applied to the electrodes 5 and 6. Namely, large variation in the effective shapes of the electrodes 5 and 6 between a high and a low frequency is utilized. Consequently, the DC drift can be suppressed and operation characteristic variation due to the DC drift or stress can be compensated effectively.

34. 发明专利

JP2003195244A OPTICAL WAVELENGTH FILTER 审中-公开
公开(公告)号：JP2003195244A
公开(公告)日：2003-07-09
申请号：JP2001399240
申请日：2001-12-28
申请人： FUJITSU LTD
发明人： NAKAZAWA TADAO , MIYATA HIDEYUKI , DOI MASAHARU
IPC分类号： G02F1/11 , G02F1/125
摘要： PROBLEM TO BE SOLVED: To provide a band rejection type optical wavelength filter capable of reliably and stably blocking passing of light of a required wavelength. SOLUTION: This band rejection type optical wavelength filter 1A is provided with a plurality of optical filter parts 11 and 12 blocking the passing of the light corresponding to selected wavelengths λ1 and λ2 and the optical filter parts 11 and 12 are cascade-connected to form a multi-stage constitution. By shifting the selected wavelength λ1 and λ2 of the optical filter parts 11 and 12 from each other, a blocking band having a wavelength width corresponding to the amount of shift is formed. COPYRIGHT: (C)2003,JPO

35. 发明专利

JP2001194640A DRIVING METHOD OF ACOUSTOOPTICAL FILTER, ACOUSTOOPTICAL FILTER, AND EXTENSION METHOD OF SELECTED WAVELENGTH, OPTICAL BRANCHING AND INSERTION DEVICE, AND OPTICAL COMMUNICATION SYSTEM 失效
公开(公告)号：JP2001194640A
公开(公告)日：2001-07-19
申请号：JP2000007038
申请日：2000-01-14
申请人： FUJITSU LTD
发明人： NAKAZAWA TADAO
IPC分类号： G02F1/11 , H04B10/07 , H04B10/2507 , H04B10/291 , H04B10/40 , H04B10/50 , H04B10/60 , H04J14/02 , H04B10/02 , H04B10/28
摘要： PROBLEM TO BE SOLVED: To provide an acoustooptical filter driving method, an acoustooptical filter, an extension method of a selected wavelength, an optical branching and insertion device, and an optical communication system enabling to miniaturize a driving device which can suppresse a temporal variation of output characteristics in the acoustooptical filter. SOLUTION: When distributing RF signals to the number matched to the number of stages of AOTFs 16 which is cascade connected, while adjusting the phase of RF signal, after collecting RF signals whose phases are adjusted identically to distribute and dividing a plurality of RF signals into groups, RF signals are put in block for every group. The signals in bloc are distributed to the number of stages, adjusting the phases so that phases of beats generated from a plurality of RF signals to one AOTF 16 become different phases between a plurality of AOTF 16.

36. 发明专利

JP2000314862A DRIVING METHOD OF ACOUSTIC OPTICAL FILTER AND ACOUSTIC OPTICAL FILTER DEVICE 失效
公开(公告)号：JP2000314862A
公开(公告)日：2000-11-14
申请号：JP2000101616
申请日：2000-04-03
申请人： FUJITSU LTD
发明人： NAKAZAWA TADAO , ONAKA HIROSHI , KIYONO MINORU
IPC分类号： G02F1/11 , G02F1/125
摘要： PROBLEM TO BE SOLVED: To make reducible variation in the center wavelength for performing a band pass and a band rejection by shifting the phases of beat components generated in plural RF signals to be added to an acoustic optical filter(AOTF). SOLUTION: A 1st AOTF 1 inputs frequencies f1, f3 as RF signals corresponding to a wavelength 1 and a wavelength 3 to a transducer 15-1, and separates light of wavelengths 1-8 as input light 1 by an optical waveguide PBS 16-1, and a TM mode light is made incident on an optical waveguide 11-1 and a TE mode light is made incident on an optical waveguide 12-1. The wavelengths 1, 3 are outputted from the output 2 side, and the wavelengths 2, 4-8 are outputted from the output 1 side. A 2nd AOTF 2 inputs frequencies f2, f4 of the RF signal to a transducer 15-2, separates the wavelengths 2, 4-8 by optical waveguide PBS 16-2, makes TM mode light incident on an optical waveguide 11-2, makes TE mode light incident on an optical waveguide 12-2, and outputs wavelengths 2, 4 from the output 2 side, and the wavelength 4-8 from the output 1 side. In such a manner, it is possible to segment individual wavelengths centering a specific wavelength.

37. 发明专利

JPH1164809A OPTICAL WAVEGUIDE DEVICE AND OPTICAL COMMUNICATION SYSTEM USING OPTICAL WAVEGUIDE DEVICE 失效
公开(公告)号：JPH1164809A
公开(公告)日：1999-03-05
申请号：JP21605097
申请日：1997-08-11
申请人： FUJITSU LTD
发明人： KIYONO MINORU , NAKAZAWA TADAO , TANIGUCHI SHINJI
IPC分类号： G02B6/125 , G02F1/01 , G02F1/125 , G02F1/21
摘要： PROBLEM TO BE SOLVED: To embody an efficient plane surface acoustic wave(SAW) waveguide and to increase the degree of freedom in design for control of filter characteristics by forming a thin film on the surface of a substrate and forming the substrate surface as a ridge structure. SOLUTION: The transparent thin film 18 of SiO2 , etc., is formed in approximately the same direction as the direction of optical waveguides 11, 12 for propagation in an approximately X- or Y-axis direction formed within the surface of the LnNbO3 substrate in such a manner that the substrate surface is formed to the ridge shape. Namely, the optical waveguides 11, 12 extending in the y-axis direction are formed on the x-cut LnNbO3 substrate 10 and a transducer 15 for generating SAW is formed thereon. A SAW absorber consisting of a resist is formed between the light input side of the LnNbO3 substrate 10 and the transducer 15. The thin film 18 for the SAW waveguide consisting of the SiO2 film having the refractive index lower than the refractive index of the LnNbO3 substrate is formed on the waveguide behind the same. The SAW absorber 20 consisting of the resist is formed in front of an electrode and at the final point of the thin film 18 for the SAW waveguide.

38. 发明专利

JPH0990303A WAVELENGTH FILTER 失效
公开(公告)号：JPH0990303A
公开(公告)日：1997-04-04
申请号：JP24617995
申请日：1995-09-25
申请人： FUJITSU LTD
发明人： NAKAZAWA TADAO
IPC分类号： G02F1/125
摘要： PROBLEM TO BE SOLVED: To obtain a wavelength filter capable of simply and easily improving side lobe characteristics by adequately changing the positional relation between an optical waveguide and a surface acoustic waveguide in the longitudinal direction of the optical waveguide. SOLUTION: The waveguide of Y propagation is formed on a substrate constituting this wavelength filter and comb-shaped electrodes of a logarithm 5 for exciting surface acoustic waves are formed of Al on the incident side. An absorber 5 formed of a resin, etc., is arranged on the exit side to absorb the surface acoustic waves. The surface acoustic waveguide 2 has a width uniform to the propagation direction. The intensity of the surface acoustic waves on the optical waveguide 4 formed on a straight line is changed by curving the surface acoustic waveguide 2. When the distance between the optical waveguide 4 and the surface acoustic waveguide 2 is defined as f(x), the function examples thereof are conceivably a function including the trigonometric function, such as f(x)=0.85Wl-cos(πx/L)/2, and a straight line, such as f(x)=0.85(W/L)x. L is the interaction length.

39. 发明专利

JPH08254674A OPTICAL FUNCTION DEVICE 失效
公开(公告)号：JPH08254674A
公开(公告)日：1996-10-01
申请号：JP5838795
申请日：1995-03-17
申请人： FUJITSU LTD
发明人： NAKAZAWA TADAO
IPC分类号： G02B6/12 , G02F1/035
摘要： PURPOSE: To improve the wavelength selectivity of mode conversion by constituting, an optical function device in such a manner that respective electrodes are changed in arranging density along a light propagation direction. CONSTITUTION: A mode converter 1 is composed of a substrate 11 of an electro- optical material, an optical waveguide 1, a pair of comb-shaped electrodes 14, 15 for impressing electric fields to the optical waveguide 12 and a buffer layer 13. The arranging spacings of electrode fingers 14a, 15a are set in compliance with a Hamming function in a mode converter 1 and, therefore, the electric field distribution of the density decreasing gradually from the central part to the end of the light propagation direction is generated in an optical waveguide 12 when bus cylindrical body parts 14b, 15b are connected to a power source for outputting a specified voltage. The light propagating in the optical waveguide 12 is rotated in the polarization direction by the angle meeting the intensity of the electric fields by passing the electric fields. As a result, mode conversion is realized between a TE mode and TM mode for light of the selected wavelength if the impression voltage is set according to the electrode length L of the comb-shaped electrodes 14, 15.

40. 发明专利

JPH06160787A OPTICAL WAVEGUIDE DEVICE 失效
公开(公告)号：JPH06160787A
公开(公告)日：1994-06-07
申请号：JP31068092
申请日：1992-11-20
申请人： FUJITSU LTD
发明人： NAKAZAWA TADAO
IPC分类号： G02B6/12 , G02F1/035 , G02F1/313
摘要： PURPOSE:To eliminate an operating point offset and to improve reliability by providing plural slender gaps at the boundary face of the plural electrodes provided in proximity to the optical waveguide on a transparent substrate consisting of an electrooptical crystal and the optical waveguide. CONSTITUTION:The optical waveguide 2 is formed on the substrate 1 consisting of the Z-cut LiNbO3 crystal and an SiO2 film is formed on the substrate 1 including the optical waveguide 2, by which a buffer layer 6 is formed. After an Au film pattern is formed to a state of arraying 3 pieces of slender vapor deposited films, the Au is grown to form the electrodes 4 at the time of forming the Au film by a vacuum vapor deposition method and forming vapor deposited metallic patterns 11 by a photoetching technique. The spacings 12 of the electrodes 4 formed in such a manner are slender tunnel-like spacings having semicircular sections and the strains generated in the substrate at the time of forming the vapor deposited metallic patterns 11 and the electrodes 4 are absorbed by the spacings 12. Consequently, the stresses generated in the substrate 1 at the time of forming the electrodes 4 is relieved and the operating point offset is eliminated.

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