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WO1998006001A1 - Reseau de bragg a fibre guide d'onde optique - Google Patents

Reseau de bragg a fibre guide d'onde optique Download PDF

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Publication number
WO1998006001A1
WO1998006001A1 PCT/US1997/013442 US9713442W WO9806001A1 WO 1998006001 A1 WO1998006001 A1 WO 1998006001A1 US 9713442 W US9713442 W US 9713442W WO 9806001 A1 WO9806001 A1 WO 9806001A1
Authority
WO
WIPO (PCT)
Prior art keywords
birefringence
waveguide
intrinsic
polarization
waveguide structure
Prior art date
Application number
PCT/US1997/013442
Other languages
English (en)
Inventor
Robert A. Modavis
Original Assignee
Corning Incorporated
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Corning Incorporated filed Critical Corning Incorporated
Priority to CA002225342A priority Critical patent/CA2225342A1/fr
Priority to JP10508051A priority patent/JP2000502469A/ja
Priority to EP97938074A priority patent/EP0864115A4/fr
Priority to AU40487/97A priority patent/AU729859B2/en
Priority to US08/973,835 priority patent/US5881187A/en
Publication of WO1998006001A1 publication Critical patent/WO1998006001A1/fr

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/02—Optical fibres with cladding with or without a coating
    • G02B6/02057—Optical fibres with cladding with or without a coating comprising gratings
    • G02B6/02076—Refractive index modulation gratings, e.g. Bragg gratings
    • G02B6/0208—Refractive index modulation gratings, e.g. Bragg gratings characterised by their structure, wavelength response
    • G02B6/021—Refractive index modulation gratings, e.g. Bragg gratings characterised by their structure, wavelength response characterised by the core or cladding or coating, e.g. materials, radial refractive index profiles, cladding shape
    • G02B6/02109—Refractive index modulation gratings, e.g. Bragg gratings characterised by their structure, wavelength response characterised by the core or cladding or coating, e.g. materials, radial refractive index profiles, cladding shape having polarization sensitive features, e.g. reduced photo-induced birefringence
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C25/00—Surface treatment of fibres or filaments made from glass, minerals or slags
    • C03C25/62—Surface treatment of fibres or filaments made from glass, minerals or slags by application of electric or wave energy; by particle radiation or ion implantation
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C25/00—Surface treatment of fibres or filaments made from glass, minerals or slags
    • C03C25/62—Surface treatment of fibres or filaments made from glass, minerals or slags by application of electric or wave energy; by particle radiation or ion implantation
    • C03C25/6206—Electromagnetic waves
    • C03C25/6208—Laser

Definitions

  • the invention is directed to a method for forming a
  • Bragg grating m an optical waveguide fiber. More particularly, the novel method includes steps which minimize birefringence m the grating.
  • Light-sensitive optical fibers and planar waveguides Kashyap et al . , BT Techno., 1, Vol. 11, No. 2, Apr. 1993.
  • the publication discusses the making of li ⁇ ,ht-induced reflection gratings, page 150, section 2.1, and notes that the amount of refractive index change increases as light wavelength is reduced from 600 nm to 240 n , where the photosensitivity of the waveguide appears to peak.
  • the twice-polarization dependent induced birefringence is a factor m the range of about 4 to 12 smaller than the polarization dependent induced birefringence.
  • this smaller amount of birefringence is undesirable.
  • a more versatile and effective grating would result from a writing method which produces a grating having minimal birefringence.
  • An optical waveguide grating is a periodic variation m refractive index of the waveguide along the long axis of the waveguide.
  • Photo-sensitivity is an interaction between certain glass compositions and selected light wavelengths wherein incident light changes the refractive index or the loss characteristics of the irradiated glass.
  • - Side writing is a technique for forming . grating in an optical waveguide fiber wherein light is caused to form a periodic series of alternating light and dark fringes along the long axis of the waveguide.
  • An example of such a periodic series is an interference pattern formed on the side of a waveguide fiber and along a portion of the long axis of a waveguide fiber.
  • the periodic light intensity pattern, produced by the light interference induces a periodic change in refractive index along a portion of the long axis of the waveguide fiber.
  • a phase mask may be a transmission diffraction grating, a component whose structure and characteristics are known in the art.
  • a phase mask may also be a substrate having a series of periodically spaced openings.
  • the phase mask may be used to side write a grating on a waveguide fiber wherein no optical components are positioned between the waveguide and the phase mask.
  • the novel method for writing a Bragg grating m a waveguide structure meets the need for a method of writing a grating ha ng minimal birefringence, thereby overcoming the deficiency in the prior art .
  • the method comprises the steps: a) finding the orientation of the slow axis m the waveguide and the magnitude of the non-polarization dependent (intrinsic) induced birefringence, where the birefringence magnitude is described by ) n , the difference in refractive index between the fast and slow axis of the intrinsic birefringence; b) finding the magnitude of the total, i.e., polarization dependent and intrinsic induced birefringence, )n ts ; and, c) writing a Bragg grating, using linearly polarized light, wherein the angle included between ne polarization direction and the long axis of the waveguide structure is chosen such that the induced intrinsic birefringence together with the induced polarization dependent birefringence yields minimal birefringence. That is, the relative direction of the intrinsic slow axis compared to the polarization dependent slow axis is chosen such that the refractive index shows minimal anisotropy after the grating
  • the intrinsic slow axis is found by directing light onto the waveguide structure.
  • the light may be randomly polarized, circularly polarized, or linearly polarized, provided, m the latter case, the polarization direction is oriented parallel to the waveguide structure long axis.
  • the magnitude and orientation of the intrinsic induced birefringence is found by conventional means such as those described m the Meltz et al . or Amsterdam et al . publications cited above.
  • the total induced birefringence is found by illuminating the waveguide structure with linearly polarized light having its polarization direction oriented perpendicular to the waveguide structure long axis and parallel to the intrinsic slow axis direction found initially.
  • This orientation is selected b e cause, as noted in Bach et al., this orientation of the polarization yields a maximum polarization dependent birefringence and forms the polarization dependent slow axis along the intrinsic slow axis.
  • the polarized light increases refractive index along the direction of polarization by an amount greater than it does in a direction perpendicular to both the long axis and the polarization direction.
  • the slow axis of the polarization dependent birefringence will be parallel to the polarization direction.
  • a sum of intrinsic and polarization dependent biref ingence is induced in the waveguide structure. Then ) n p3 can be found by taking the difference, ) n t - )n 13 .
  • a Bragg grating is written along a segment of the waveguide structure long axis.
  • the orientation of the linear polarization of the writing light, relative to the slow axis of the intrinsic birefringence, is chosen to minimize birefringence. That is, the writing geometry is chosen such that intrinsic induced birefringence and the polarization induced birefringence serve to substantially cancel one another.
  • the waveguide segment upon which the grating is written is located near the segments used to determine the intrinsic and polarization dependent birefringence properties. Given the high purity and uniformity of waveguide structures, it is reasonable to assume that the glass properties do not change significantly over the waveguide length required to carry out the three step method.
  • the waveguide structure may have many specific forms including that of a waveguide fiber or a planar waveguide, wherein any of these are made by any of the methods known in the art .
  • any of numerous side illumination techniques may be used to write the Bragg grating in the waveguide structure. These include interferometric methods which employ a phase mask, a transmission grating, or a beam splitter. Other side writing methods may use only a phase mask or point illumination along the waveguide structure.
  • the light source for carrying out the method may be any of several types, including lasers, or incandescent, vapor type, or fluorescent lamps.
  • the wavelength range of the source is about 100 nm to 600 nm and the coherence length is in the range of 10 :m to several meters.
  • the grating may be written m a number of waveguide structures including, optical waveguide fiber, a planar optical waveguide, or a planar optical waveguide component such as a coupler or multiplexer.
  • FIG. la is an end view of a waveguide structure showing the orientation of the fast and slow axis of a birefringence.
  • FIG. lb is an end view of a waveguide structure showing the relative refractive index co ⁇ > sponding to the fast and slow axis of birefringence.
  • FIG. 2 is a side view of a waveguide structure showing the long axis of the waveguide, a birefringent axis in the waveguide and an incident polarized light beam.
  • FIG. 3a is a side view of a waveguide structure showing the long axis of the waveguide, a birefringent axis in the waveguide and incident, overlapping light beams .
  • FIG. 3b is a schematic view of FIG. 3a for use in relating the polarization direction to the orientation of the intrinsic slow axis.
  • FIG. 4 is an end view of a waveguide structure showing the angle between the intrinsic slow axis a polarization dependent slow axis .
  • the novel method of forming a minimal birefringence Bragg grating in a waveguide structure relates to the control of two distinct types of glass photosensitivity.
  • a first interaction type results from the interaction of essentially unpolarized light or circularly polarized light or linearly polarized light, having the polarization direction along the long axis of the waveguide, with particular glass compositions.
  • the interaction produces a birefringence in the glasses which is called intrinsic birefringence.
  • Intrinsic birefringence is distinguished from polarization dependent birefringence, wherein the glass is sensitive to the polarization direction of incident light.
  • FIG. la is an end view of a waveguide structure 2 showing the mutually perpendicular birefringence axes 4 and 6.
  • Light having a polarization direction aligned along one axis propagates at a higher speed in comparison to light having its polarization aligned the other axis.
  • the former may be called the fast axis and the latter the slow axis.
  • the relative refractive index along the fast axis compared to the slow axis is illustrated in FIG. lb.
  • the lower refractive index shown as arrow 5 is the fast axis and the higher refractive index shown as arrow 3 is the slow axis.
  • FIG. 2 An experimental configuration for de .rmirung total birefringence is illustrated m FIG. 2.
  • the waveguide structure 2 is shown in side view.
  • Light beam 8 having a polarization direction 10 is incident on waveguide structure 2.
  • the light beam 8 is substantially perpendicular to the long axis 7 of the waveguide structure 2.
  • the slow axis 9 of the intrinsic birefringence is oriented to lie along polp ⁇ zation direction 10. It is known that orienting polarization direction 10 perpendicular to long axis 7 yields a maximum polarization dependent induced birefnnge'i -e and that the slow axis thereof lies along the polarization direction 10 as noted above. Thus, a maximum total birefringence is induced m the configuration wherein intrinsic slow axis 9, which is perpendicular to axis 7, is aligned with polarization direction 10.
  • Coherent beams 12 are incident on waveguide structure 2 and interfere there to produce light and dark fringes on strur ire 2.
  • the intrinsic slow axis 9 is oriented relative to polarization direction 10 to produce a minimum birefringence m the waveguide after the grating is written. The details of how polarization 10 and intrinsic slow axis 9 are to be oriented are now discussed with reference to FIG. 3b.
  • the plane 22 is defined by light beam 12 and its polarization 10. Note that 12 and 10 are perpendicular.
  • the plane 20 is defined by the waveguide centerline 7 and the vertical 26 which is perpendicular to 7. Planes 20 and 22 intersect to form line 24. Beam 12 and intersection 24 form an included angle 14.
  • the projection of polarization 10 onto line 24 is (10) sm 14, where (10) denotes the magnitude of the pr . ⁇ zation vector.
  • the intersection 24 and vertical 26 form an included angle 18.
  • the projection of (10) onto waveguide axis 7 is (10) sm 14 sm 18.
  • the magnitude of (10) which is perpendicular to waveguide axis 7 is, by difference, (10) (1 - s 14 s - 18) J/ - .
  • angle 30 is cos "1 ⁇ sm 14 cos 18/(1 - 5 sm 2 14 sm 18) 17 - ⁇ .
  • An alternative writing method may be used when ) __ is small compared to the minimum value of ) n ps .
  • a grating may be written one fringe at a time.
  • Intrinsic Birefringence The magnitude and slow axis direction of the intrinsic birefringence s found as follows.
  • a germanium doped step index waveguide fiber is illuminated from the side using a linearly polarized excimer laser.
  • the laser operates at a wavelength near 248 nm.
  • the laser operates at a rate of about 10 Hz and the waveguide is illuminated for a time the range of 1 - 10 minutes.
  • the laser beam direction forms a right angle with the long axis of the fiber, the beam having a polarization parallel to the long axis of the fiber, so that essentially no polarization dependent birefringence is induced.
  • the induced birefringence is called intrinsic because the birefringence depends upon the properties of the waveguide glass rather than the polarization direction of the incident light beam.
  • the intrinsic birefringence is measured by finding the orientation of the slow axis and by fi l ling )n lr , the refractive index difference between the fast and slow axes. Conventional measurement means known in the art are used.
  • the total birefringence is induced m a short section of the waveguide fiber, located near the section used in the first step, by orienting and operating the excimer laser as before except that the polarization direction of the incident light is disposed perpendicular to the long axis of the waveguide fiber.
  • the intrinsic slow axis is aligned parallel to the polarization direction.
  • the assumption is made that the direction of the intrinsic slow axis will not change appreciably for short distances, of the order of several tens of centimeters, along the waveguide fiber.
  • the excellent composition and geometry con t rol possible in the manufacture of optical waveguide fibers and other waveguide structures lends credence to the validity of the assumption.
  • the total induced birefringence is measured as before.
  • the slow axis orientation lies along the polarization direction of the fiber.
  • a preferred method includes a phase mask or transmission grating, illuminated by an excimer laser, as the light source for an interferometer.
  • the angle of incidence of the interfering light beams, 14 in FIG. 3a is noted.
  • the condition wherein ) n 15 is most nearly equal to ) n p is achieved by adjusting angles 18 and 14 as described above.
  • the resulting grating has minimum birefringence.

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  • Life Sciences & Earth Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Optics & Photonics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Optical Integrated Circuits (AREA)
  • Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)

Abstract

On décrit un procédé d'écriture latérale sur des réseaux de Bragg possédant une biréfringence minimale, dans une structure de guide d'onde (2). Dans ce procédé, on utilise l'orientation du sens de polarisation (10) du faisceau lumineux d'écriture (8) par rapport à l'axe long (7) de la structure de guide d'onde (2), en même temps que l'orientation de l'axe lent de biréfringence intrinsèque (9), afin de minimiser de manière efficace la biréfringence du réseau en question.
PCT/US1997/013442 1996-08-07 1997-07-29 Reseau de bragg a fibre guide d'onde optique WO1998006001A1 (fr)

Priority Applications (5)

Application Number Priority Date Filing Date Title
CA002225342A CA2225342A1 (fr) 1996-08-07 1997-07-29 Reseau de bragg de guide d'onde optique
JP10508051A JP2000502469A (ja) 1996-08-07 1997-07-29 光導波路ファイバのブラッグ回折格子
EP97938074A EP0864115A4 (fr) 1996-08-07 1997-07-29 Reseau de bragg a fibre guide d'onde optique
AU40487/97A AU729859B2 (en) 1996-08-07 1997-07-29 Optical waveguide fiber bragg grating
US08/973,835 US5881187A (en) 1997-07-29 1997-07-29 Optical waveguide fiber bragg grating

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US2349296P 1996-08-07 1996-08-07
US60/023,492 1996-08-07

Publications (1)

Publication Number Publication Date
WO1998006001A1 true WO1998006001A1 (fr) 1998-02-12

Family

ID=21815414

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1997/013442 WO1998006001A1 (fr) 1996-08-07 1997-07-29 Reseau de bragg a fibre guide d'onde optique

Country Status (5)

Country Link
EP (1) EP0864115A4 (fr)
JP (1) JP2000502469A (fr)
AU (1) AU729859B2 (fr)
CA (1) CA2225342A1 (fr)
WO (1) WO1998006001A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000067054A1 (fr) * 1999-04-30 2000-11-09 The University Of Sydney Procede de creation d'une structure optique a l'interieur d'un materiau photosensible transmettant la lumiere, et d'augmentation de la photosensibilite de ce materiau
EP1154297A1 (fr) * 2000-05-11 2001-11-14 Alcatel Compensation de la dispersion modale de polarisation d'un réseau inscrit dans une fibre optique
WO2003021317A3 (fr) * 2001-08-29 2003-10-16 3M Innovative Properties Co Appareils optiques faisant intervenir des fibres optiques profilees et procedes de fabrication d'appareils optiques comportant des fibres optiques profilees
AU767432B2 (en) * 1999-04-30 2003-11-13 University Of Sydney, The Method for creating an optical structure within a photosensitive light transmissive material and of enhancing the photosensitivity of the photosensitive light transmissive material
CN115857087A (zh) * 2022-11-11 2023-03-28 上海频准激光科技有限公司 交叉对准光纤光栅对的波长自匹配刻写系统及方法

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US5016917A (en) * 1990-01-16 1991-05-21 Dubner Daniel W Regimen calendar
US5341444A (en) * 1993-03-19 1994-08-23 At&T Bell Laboratories Polarization compensated integrated optical filters and multiplexers
US5478371A (en) * 1992-05-05 1995-12-26 At&T Corp. Method for producing photoinduced bragg gratings by irradiating a hydrogenated glass body in a heated state
US5499154A (en) * 1994-12-20 1996-03-12 Stewart Electronics Protective shut-down system for switch-mode power supply

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5104209A (en) * 1991-02-19 1992-04-14 Her Majesty The Queen In Right Of Canada, As Represented By The Minister Of Communications Method of creating an index grating in an optical fiber and a mode converter using the index grating
EP0635736A1 (fr) * 1993-07-19 1995-01-25 AT&T Corp. Procédé pour former, dans des milieux optiques des perturbations d'indice de refraction avec biréfringence reduite
US5559907A (en) * 1994-02-17 1996-09-24 Lucent Technologies Inc. Method of controlling polarization properties of a photo-induced device in an optical waveguide and method of investigating structure of an optical waveguide

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5016917A (en) * 1990-01-16 1991-05-21 Dubner Daniel W Regimen calendar
US5478371A (en) * 1992-05-05 1995-12-26 At&T Corp. Method for producing photoinduced bragg gratings by irradiating a hydrogenated glass body in a heated state
US5341444A (en) * 1993-03-19 1994-08-23 At&T Bell Laboratories Polarization compensated integrated optical filters and multiplexers
US5499154A (en) * 1994-12-20 1996-03-12 Stewart Electronics Protective shut-down system for switch-mode power supply

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP0864115A4 *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000067054A1 (fr) * 1999-04-30 2000-11-09 The University Of Sydney Procede de creation d'une structure optique a l'interieur d'un materiau photosensible transmettant la lumiere, et d'augmentation de la photosensibilite de ce materiau
AU767432B2 (en) * 1999-04-30 2003-11-13 University Of Sydney, The Method for creating an optical structure within a photosensitive light transmissive material and of enhancing the photosensitivity of the photosensitive light transmissive material
US6706455B1 (en) 1999-04-30 2004-03-16 The University Of Sydney Method for creating an optical structure within a photosensitive light transmissive material and of enhancing the photosensitivity of the photosensitive light transmissive material
EP1154297A1 (fr) * 2000-05-11 2001-11-14 Alcatel Compensation de la dispersion modale de polarisation d'un réseau inscrit dans une fibre optique
FR2808887A1 (fr) * 2000-05-11 2001-11-16 Cit Alcatel Compensation de la dispersion modale de polarisation d'un reseau inscrit dans une fibre optique
US6535669B2 (en) 2000-05-11 2003-03-18 Alcatel Compensation of polarization mode dispersion of a grating written in an optical fiber
WO2003021317A3 (fr) * 2001-08-29 2003-10-16 3M Innovative Properties Co Appareils optiques faisant intervenir des fibres optiques profilees et procedes de fabrication d'appareils optiques comportant des fibres optiques profilees
CN115857087A (zh) * 2022-11-11 2023-03-28 上海频准激光科技有限公司 交叉对准光纤光栅对的波长自匹配刻写系统及方法

Also Published As

Publication number Publication date
CA2225342A1 (fr) 1998-02-07
AU729859B2 (en) 2001-02-08
AU4048797A (en) 1998-02-25
EP0864115A1 (fr) 1998-09-16
JP2000502469A (ja) 2000-02-29
EP0864115A4 (fr) 2000-02-02

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