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WO1995002202A1 - Composants a fibre optique - Google Patents

Composants a fibre optique Download PDF

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Publication number
WO1995002202A1
WO1995002202A1 PCT/GB1994/001451 GB9401451W WO9502202A1 WO 1995002202 A1 WO1995002202 A1 WO 1995002202A1 GB 9401451 W GB9401451 W GB 9401451W WO 9502202 A1 WO9502202 A1 WO 9502202A1
Authority
WO
WIPO (PCT)
Prior art keywords
fibre
component
core
overlay waveguide
waveguide
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/GB1994/001451
Other languages
English (en)
Inventor
Walter Johnstone
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
University of Strathclyde
Original Assignee
University of Strathclyde
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 University of Strathclyde filed Critical University of Strathclyde
Publication of WO1995002202A1 publication Critical patent/WO1995002202A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29331—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by evanescent wave coupling
    • G02B6/29332—Wavelength selective couplers, i.e. based on evanescent coupling between light guides, e.g. fused fibre couplers with transverse coupling between fibres having different propagation constant wavelength dependency
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/06—Construction or shape of active medium
    • H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
    • H01S3/067—Fibre lasers

Definitions

  • This invention relates to fibre optic components.
  • a fibre optic component which comprises a single-mode fibre side-polished into the core, the polished portion of the fibre being in optical contact with a comparatively high- index multimode overlay waveguide, the arrangement being such that the depth of polishing into the core is selected to be within a range where the component functions as a periodic pass-band filter to signals propagated along the fibre.
  • the fibre is side polished so that the entirety of its cladding is locally removed from one side and in addition part of the core itself is removed.
  • the extent of core removal is critical to achieve an effective periodic pass-band filter function. Too small an amount of core removal produces a characteristic which is generally periodic but the pass bands are poorly defined i.e. the line width is wide and the extinction (contrast) ratio is poor. Too great an amount of core removal produces a characteristic which is generally periodic with well defined pass-bands and a good extinction ratio but the insertion loss within the pass- bands is poor.
  • the required extent of core removal to achieve an effective filter function lies between these extremes but is dependent upon the quality of the periodic pass-band filter function which is desired as regards pass band line width, extinction ratio between the pass-bands, and insertion loss within the pass-bands.
  • Typical values which can be achieved are a linewidth of about 5nm, an extinction ratio of greater than 16dB and an insertion loss of less than 2dB.
  • the thickness and material index of the overlay waveguide may be selected to determine the position of the transmission channels and the spacing between channels. For a given value of material index the thickness of the overlay waveguide can be tailored to provide desired positioning of transmission channels and also channel spacing. Typically this thickness parameter is of the order of 30 microns or less for material indices in the range 1.47 to 2.3. Relatively thick overlay waveguides produce the narrowest transmission channels.
  • the overlay waveguide may be made of an electro-optic material such as lithium niobate and electrically controlled via a suitable electrode structure (such as indium-tin-oxide electrodes above and below the waveguide, or metal electrodes on the exposed surface of the waveguide) to vary the effective index of the modes supported by the overlay waveguide whereby to vary or tune the position of the transmission channels.
  • the overlay waveguide may carry an electro- optic superstrate which is electrically controllable, for example liquid crystals of refractive index lower than the effective refractive index of the fibre.
  • the component of the present invention may be utilised in a variety of all-fibre signal-handling systems.
  • a doped-fibre amplifier or the wavelength selective part of an all-fibre laser either of the linear type or the ring type.
  • the periodic pass-band filter component 10 illustrated in Fig. 1 comprises a single mode fibre 11 having a core 12 and a cladding 13 is supported by a substrate 14 conveniently made of glass.
  • the fibre 11 is side-polished along the plane A-A such that the cladding 13 is completely removed in the local region concerned and in addition part of core 12 is removed.
  • a comparatively high index multimode planar overlay waveguide material 15 is applied to the plane A-A and is in optical contact with the fibre 11.
  • characteristic 19 consists of a set of spaced pass-bands each of which produces some attentuation (insertion loss) on the signal transmitted along the fibre depending upon wavelength but between pass- bands the signal is almost completely extinguished.
  • the correct depth of polishing into core 12 to achieve characteristic 19 for a particular overlay waveguide 15 can be undertaken on a trial and error basis on one or more samples.
  • the power loss at the output end of the fibre on a test signal (in the required wavelength range of operation) propagated along the fibre with the polished surface exposed to air is in the region of 12 to 20dB, typically about 16dB.
  • the power loss figure need only be in the range of 6 to 30dB.
  • An alternative test procedure is periodically to measure the cut-off wavelength at the output end of the fibre on a test signal having a broad band wavelength spectrum propagated along the fibre with the polished surface exposed to air.
  • the wavelength at which cut-off is achieved reduces as the polishing depth increases.
  • the overlay waveguide 15 may be made of a variety of materials and may be applied to different thicknesses. High index waveguides 15 which are relatively thick, produce the narrowest line widths in the characteristic 19 and the spacing between pass-bands decreases as the overlay material index and thickness is increased. Particular values of these parameters are set forth in Table I for two different thicknesses (12 ⁇ m or 23 ⁇ m) of overlay waveguides with a range of refractive indices where the fibre 11 consists of a standard telecommunications 1300 nm step- index single mode fibre supplied by Optical Fibres Limited.
  • the Table I parameters were determined using as the overlay waveguide Cargille refractive index oils having 5 different n values.
  • the oils were confined in position by Mylar spacers and a polished fused silica superstrate.
  • the characteristic 19 which resulted was essentially insensitive to polarisation.
  • the overlay waveguide may be a thin slice of Z-cut lithium niobate having a refractive index of 2.2.
  • One surface of the slice was polished and bonded to the remainder of the component 10 along the plane A-A using a UV-cured optical glue of refractive index 1.5 and having a thickness of the order of 1-3 ⁇ m.
  • the thin slice was then polished down on its other face to a thickness of 7 ⁇ m.
  • the response from the component 10 was then measured and was found to be similar to characteristic 19 of Fig. 2 for each of the TE and TM polarisations with the pass-bands of the two polarisations interlaced.
  • Fig. 3 illustrates the component 10 forming part of a tunable ring laser 22.
  • the fibre 11 of component 10 is spliced at position 23 to a pump beam coupler 24 and at position 25 to output beam coupler 26.
  • These couplers 24,26 are also spliced at locations 27, 28 to a bobbin of active fibre 29 which forms the gain medium.
  • coupler 24 may be a 980 nm coupler arranged to receive a 980 nm pump beam from a source (not shown) whilst the output coupler 26 may be a 1550 nm coupler and the component 10 is arranged so that it has a pass-band within the range 1520 nm to 1580 nm and can be tuned within that range.
  • the active fibre 29 conveniently is an erbium doped fibre.
  • the ring laser 22 is a wavelength tunable all-fibre laser and, of course, component 10 can additionally be electrically driven to modulate, mode-lock or Q-switch the laser 22.

Landscapes

  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Optical Integrated Circuits (AREA)

Abstract

Un filtre à bande passante périodique est constitué sous forme d'un composant (10) à fibre optique comprenant une fibre monomode (11). La gaine (13) de la fibre (11) est latéralement enlevée par polissage jusqu'à l'âme (12) de la fibre sur une certaine longueur de celle-ci, et la partie polie est mise en contact optique avec un guide d'ondes (15) de recouvrement multimode à indice relativement élevé. Le guide d'ondes (15) peut être électro-optique et pourvu d'électrodes qui rendent actif le composant. L'étendue d'enlèvement d'âme requise est déterminée de manière expérimentale au cours de la production, selon la qualité de la fonction de filtrage du filtre à bande passante périodique, mais des valeurs typiques comprennent une largeur spectrale d'environ 5 nm, un rapport d'extinction supérieur à 16 dB et une perte d'insertion inférieure à 2 dB.
PCT/GB1994/001451 1993-07-06 1994-07-05 Composants a fibre optique Ceased WO1995002202A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9313915.2 1993-07-06
GB939313915A GB9313915D0 (en) 1993-07-06 1993-07-06 Fibre optic components

Publications (1)

Publication Number Publication Date
WO1995002202A1 true WO1995002202A1 (fr) 1995-01-19

Family

ID=10738346

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1994/001451 Ceased WO1995002202A1 (fr) 1993-07-06 1994-07-05 Composants a fibre optique

Country Status (2)

Country Link
GB (1) GB9313915D0 (fr)
WO (1) WO1995002202A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998032048A1 (fr) * 1997-01-21 1998-07-23 Molecular Optoelectronics Corporation Amplificateur de guide d'ondes optique
US6489399B1 (en) 2000-07-31 2002-12-03 Molecular Optoelectronics Corp. Dye-appended polymers for broadband fiber optic devices
KR100782603B1 (ko) 2006-04-13 2007-12-06 김광택 측면 연마된 열확산 코어 광섬유를 이용한 단파장 통과필터
CN100378478C (zh) * 2006-04-28 2008-04-02 中国科学技术大学 多模光纤抛磨选模器

Non-Patent Citations (5)

* Cited by examiner, † Cited by third party
Title
C.A.MILLAR ET AL.: "EXPOSED-CORE SINGLE-MODE-FIBER CHANNEL-DROPPING FILTER USING A HIGH-INDEX OVERLAY WAVEGUIDE", OPTICS LETTERS., vol. 12, no. 4, April 1987 (1987-04-01), NEW YORK US, pages 284 - 286 *
D.G.MOODIE ET AL.: "WAVELENGTH TUNABILITY OF COMPONENTS BASED ON THE EVANESCENT COUPLING FROM A SIDE-POLISHED FIBER TO A HIGH-INDEX-OVERLAY WAVEGUIDE", OPTICS LETTERS., vol. 18, no. 12, 15 June 1993 (1993-06-15), NEW YORK US, pages 1025 - 1027 *
H.OKAMURA ET AL.: "ULTRAHIGH-FINESSE,BIDIRECTIONAL Er-DOPED FIBRE RING RESONATOR", ELECTRONICS LETTERS, vol. 28, no. 3, 30 January 1992 (1992-01-30), ENAGE GB, pages 326 - 327 *
K.MCCALLION ET AL.: "INVESTIGATION OF OPTICAL FIBRE SWITCH USING ELECTRO-OPTIC INTERLAYS", ELECTRONICS LETTERS, vol. 28, no. 4, 13 February 1992 (1992-02-13), ENAGE GB, pages 410 - 411 *
K.MCCALLION ET AL.: "TUNABLE IN-LINE FIBER-OPTIC BANDPASS FILTER", OPTICS LETTERS., vol. 19, no. 8, 15 April 1994 (1994-04-15), NEW YORK US, pages 542 - 544 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998032048A1 (fr) * 1997-01-21 1998-07-23 Molecular Optoelectronics Corporation Amplificateur de guide d'ondes optique
US6489399B1 (en) 2000-07-31 2002-12-03 Molecular Optoelectronics Corp. Dye-appended polymers for broadband fiber optic devices
KR100782603B1 (ko) 2006-04-13 2007-12-06 김광택 측면 연마된 열확산 코어 광섬유를 이용한 단파장 통과필터
CN100378478C (zh) * 2006-04-28 2008-04-02 中国科学技术大学 多模光纤抛磨选模器

Also Published As

Publication number Publication date
GB9313915D0 (en) 1993-08-18

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