Source: http://www.google.com/patents/US20040218869?dq=6101531
Timestamp: 2017-07-22 21:32:32
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Matched Legal Cases: ['art 5', 'art 5', 'arts 8', 'arts 8', 'arts 14', 'arts 14', 'art 5', 'art 5', 'arts 8', 'arts 14', 'arts 15', 'art 15']

Patent US20040218869 - Multiple split optical waveguide - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsDisclosed is a multiple split optical waveguide in which a branch waveguide path at an output end of a branch part of a first stage defines an acute angle with respect to an input waveguide path, and a branch waveguide path at an input end of a branch part of an n-th stage is no more inclined toward...http://www.google.com/patents/US20040218869?utm_source=gb-gplus-sharePatent US20040218869 - Multiple split optical waveguideAdvanced Patent SearchTry the new Google Patents, with machine-classified Google Scholar results, and Japanese and South Korean patents.Publication numberUS20040218869 A1Publication typeApplicationApplication numberUS 10/483,507PCT numberPCT/JP2002/003698Publication dateNov 4, 2004Filing dateApr 12, 2002Priority dateJul 13, 2001Also published asCA2451466A1, CA2451466C, DE60227258D1, EP1407300A1, EP1407300B1, US7116867, WO2003009030A1Publication number10483507, 483507, PCT/2002/3698, PCT/JP/2/003698, PCT/JP/2/03698, PCT/JP/2002/003698, PCT/JP/2002/03698, PCT/JP2/003698, PCT/JP2/03698, PCT/JP2002/003698, PCT/JP2002/03698, PCT/JP2002003698, PCT/JP200203698, PCT/JP2003698, PCT/JP203698, US 2004/0218869 A1, US 2004/218869 A1, US 20040218869 A1, US 20040218869A1, US 2004218869 A1, US 2004218869A1, US-A1-20040218869, US-A1-2004218869, US2004/0218869A1, US2004/218869A1, US20040218869 A1, US20040218869A1, US2004218869 A1, US2004218869A1InventorsFumio TakahashiOriginal AssigneeFumio TakahashiExport CitationBiBTeX, EndNote, RefManPatent Citations (2), Referenced by (3), Classifications (8), Legal Events (6) External Links: USPTO, USPTO Assignment, EspacenetMultiple split optical waveguide
US 20040218869 A1Abstract
Disclosed is a multiple split optical waveguide in which a branch waveguide path at an output end of a branch part of a first stage defines an acute angle with respect to an input waveguide path, and a branch waveguide path at an input end of a branch part of an n-th stage is no more inclined toward a central axial line defined by an extension line of the input waveguide path than a branch waveguide path at an input end of a branch part of an (n+1)-th stage, n being an integer equal to or greater than two. Thus, the waveguide paths are prevented from spreading beyond the first branch angle, and it becomes easier to bring the outer waveguide guide paths back toward the center. This prevents an increase in the variations in length between the outer and inner waveguide paths. Images(4) Claims(13)
BRIEF DESCRIPTION OF THE DRAWINGS [0016] Now the present invention is described in the following with reference to the appended drawings, in which: [0017] [0017]FIG. 1 is a plan view of an eight-way branch optical waveguide 1 embodying the present invention; [0018] [0018]FIG. 2 is a fragmentary enlarged view of an essential part of FIG. 1; [0019] [0019]FIG. 3 is a graph showing the relationship between the symmetric range and split ratio in a Y branch part; [0020] [0020]FIG. 4 is a plan view showing a conventional multiple branch optical waveguide; and [0021] [0021]FIG. 5 is a plan view showing a conventional multiple branch optical waveguide.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0022] [0022]FIG. 1 is a plan view of an eight-way branch optical waveguide 1 embodying the present invention. A plurality of waveguide paths are formed in a glass substrate in a per se known manner, and include an input waveguide path 3 extending linearly from an end 2 a of the substrate 2 and reaching a Y branch part 5 of the first stage. Two branch waveguide paths 6 and 7 extend from the Y branch part 5 of the first stage, and somewhat curve away from each other and reach two Y branch parts 8 and 9 of the second stage, respectively. Each of the Y branch parts 8 and 9 of the second stage splits the corresponding waveguide path of the input end into two parts each of which reaches a corresponding one of four Y branch parts 14 to 17 of the third stage. Eight branch waveguide paths 18 to 25 split by the Y branch parts 14 to 17 of the third stage and extending therefrom reach the corresponding exit ports on the other end 2 b of the substrate 2 as output waveguide paths. The eight-way branch waveguide 1 as a whole is symmetric about the axial line of the incident light of the Y branch part 5 of the first stage. [0023] Suppose that the angle formed between the central axial line O of the incident light beam of the Y branch part 5 of the first stage or an extension line of the input waveguide path 3 and the central axial line O2 of the incident light beam of each of the Y branch parts 8 and 9 of the second stage or an extension line of each of the branch waveguide paths 6 and 7 is θ0. Suppose also that the angle formed between the central axial line O of the input waveguide path 3 and the central axial line O3 of the incident light beam of each of the outer most Y branch parts 14 and 17 of the third stage or an extension line of each of the input waveguide paths 10 and 13 is θ. Then, θ0=θ. In other words, the central axial line O2 is in parallel with the central axial line O3. [0024] As shown in FIG. 2 in an enlarged and somewhat exaggerated view, each of the Y branch parts, for instance one of the inner Y branch parts 15 (16) is symmetric with respect to the central axial line over a range of 200 μm extending from the branch point 15 a (16 a), but ceases to be so downstream of that part. This simplifies the adjustment of the length of each waveguide path. It may create a concern that the asymmetric arrangement of the waveguide paths could prevent the even distribution (1 to 1 or 50-50%) of the light between the branch waveguide paths. However, it was found that the distribution ratio is worse than 50.2-49.8% if the symmetric range extends at least 200 μm from the branch point as shown in FIG. 3, and practically no problem arises. [0025] Referring to FIG. 1, each of the inner Y branch parts for instance the Y branch part 15 (16) has a central axial line O315 which inclines toward the central axial line O of the incident light. If desired, the central axial line O315 may extend in parallel with the central axial line O. This even further simplifies the adjustment of the length of each of the waveguide paths. The branch waveguide paths 6, 7, 10 to 13, and 18 to 25 are formed by curves or combinations of straight lines and curves. If the curves consist of arcs (segments of circles), the adjustment of the length of each of the waveguide paths is simplified as compared to the case of using other curves. [0026] The table given below compares the length of the substrate between the multiple branch waveguide 1 of the present invention and the conventional multiple branch waveguide shown in FIG. 4 for a given transmission loss, and the insertion losses for a given length of the substrate. TABLE 2 invention conventional remarks length 16 mm 25 mm same loss (9.9 dB)] insertion loss 9.5 dB 9.9 dB same substrate length (25 mm) [0027] As can be seen from this table, the multiple branch waveguide of the present invention allows the substrate length to be reduced by approximately 36% for a given loss, and the loss to be reduced by approximately 0.4 dB for a given substrate length. [0028] The foregoing description was directed to an eight-way optical waveguide, but the present invention is not limited to this embodiment but is equally applicable to other waveguides such as 16-, 32- and 64-way optical waveguides. In such a case, the central axial line of the incident light of the outer Y branch part of the fourth or more downstream stage may be in parallel with the central axial line of the incident light beam of the Y branch part of the second stage. [0029] The angle formed between the central axial line of the incident light beam of the first stage and the central axial line of the incident light beam of the outer most Y branch part of each stage may also be smaller than the angle formed between the central axial line of the incident light beam of the first stage and the central axial line of the incident light beam of each Y branch part of the second stage. In such a case, the design work may get somewhat complicated, but similar advantages can be gained. [0030] The substrate used in the embodiment described above consisted of glass, but may also consist of quartz, LiNbO3 containing Ti diffused therein, compound semiconductor or plastic material. [0031] As can be appreciated from the foregoing description, according to the preferred embodiment of the present invention, in a multiple split optical waveguide including three or more Y branch parts in a substrate each splitting incident light beam evenly into two parts, a central axial line of an incident light beam of a Y branch part of the second or any subsequent stage is inclined with respect to a central axial line of an incident light beam of a Y branch part of the first stage in such a manner that a certain angle θ0 is formed between the central axial line of the incident light beam of the Y branch part of the first stage and the central axial line of an incident light beam of a Y branch part of the second stage, and a certain angle θ which is equal to or less than the angle θ0 is formed between the central axial line of the incident light beam of the Y branch part of the first stage and a central axial line of an incident light beam of an outer most branch part of the third or any subsequent stage. Therefore, the waveguide paths are prevented from spreading beyond the first branch angle θ0, and it becomes easier to bring the outer waveguide guide paths back toward the center. The reduction in the spread of the outer waveguide paths prevents an increase in the variations in length between the outer and inner waveguide paths. Thus, the distance between the input and output ends can be reduced and the substrate can be made compact without increasing the variations in the losses of the different waveguide paths of the multiple split optical waveguide. In particular, if the angle θ which is formed between the central axial line of the incident light beam of the Y branch part of the first stage and the central axial line of the incident light beam of the outer most branch part of the third or any subsequent stage is equal to or less than the angle θ0, the layout of the downstream parts of the waveguide paths and subsequent branch parts is simplified. If the branch waveguide paths of each Y branch part of the second or any subsequent stage are symmetric to each other about the central axial line of the incident light beam over a length of 200 μm or greater, and asymmetric in a part downstream thereof in such a manner that the losses of the branch waveguide paths are substantially identical to each other, the length of each waveguide path can be adjusted without creating differences in loss between different waveguide paths, and the freedom in the pattern layout of the substrate is improved. If part of or all of the inner Y branch parts of the third or any subsequent stage are inclined toward the central axial line of the incident light beam of the Y branch part of the first stage, variations in length between inner and outer waveguide paths can be reduced even further. [0032] Although the present invention has been described in terms of preferred embodiments thereof, it is obvious to a person skilled in the art that various alterations and modifications are possible without departing from the scope of the present invention which is set forth in the appended claims. Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS4760580 *Mar 31, 1987Jul 26, 1988Stc PlcLaser arrayUS6282343 *Nov 16, 1999Aug 28, 2001Samsung Electronics Co., Ltd.Optical coupler and method of manufacturing the same* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS7391954 *May 30, 2007Jun 24, 2008Corning Cable Systems LlcAttenuated optical splitter moduleUS20110075976 *Sep 30, 2009Mar 31, 2011James Scott SutherlandSubstrates and grippers for optical fiber alignment with optical element(s) and related methodsUS20130058609 *Jul 31, 2012Mar 7, 2013Elli Makrides-SaravanosAttenuated splitter module for low count output channels and related assemblies and methods* Cited by examinerClassifications U.S. Classification385/45International ClassificationG02B6/122, G02B6/28, G02B6/125Cooperative ClassificationG02B6/2804, G02B6/125European ClassificationG02B6/125, G02B6/28BLegal EventsDateCodeEventDescriptionMay 11, 2004ASAssignmentOwner name: NHK SPRING CO., LTD., JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:TAKAHASHI, FUMIO;REEL/FRAME:015319/0850Effective date: 20040324Nov 24, 2006ASAssignmentOwner name: OMRON CORPORATION, JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:NHK SPRING CO., LTD.;REEL/FRAME:018545/0585Effective date: 20061101Mar 18, 2010FPAYFee paymentYear of fee payment: 4May 16, 2014REMIMaintenance fee reminder mailedOct 3, 2014LAPSLapse for failure to pay maintenance feesNov 25, 2014FPExpired due to failure to pay maintenance feeEffective date: 20141003RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services