WO2005122479A2 - A multiport variable optical attenuator architecture, and parts thereof - Google Patents

A multiport variable optical attenuator architecture, and parts thereof Download PDF

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Publication number
WO2005122479A2
WO2005122479A2 PCT/IB2005/051878 IB2005051878W WO2005122479A2 WO 2005122479 A2 WO2005122479 A2 WO 2005122479A2 IB 2005051878 W IB2005051878 W IB 2005051878W WO 2005122479 A2 WO2005122479 A2 WO 2005122479A2
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WO
WIPO (PCT)
Prior art keywords
optical
manipulated
optical signals
architecture
manipulating means
Prior art date
Application number
PCT/IB2005/051878
Other languages
French (fr)
Other versions
WO2005122479A3 (en
Inventor
Kamal Alameh
Adam Osseiran
Sutherland Ellwood
Original Assignee
Panorama Flat Ltd.
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
Priority to AU2004903110 priority Critical
Priority to AU2004903110A priority patent/AU2004903110A0/en
Application filed by Panorama Flat Ltd. filed Critical Panorama Flat Ltd.
Priority claimed from AU2005253316A external-priority patent/AU2005253316B2/en
Publication of WO2005122479A2 publication Critical patent/WO2005122479A2/en
Publication of WO2005122479A3 publication Critical patent/WO2005122479A3/en

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Classifications

    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B6/00Light guides
    • G02B6/24Coupling light guides
    • G02B6/26Optical coupling means
    • G02B6/264Optical coupling means with optical elements between opposed fibre ends which perform a function other than beam splitting
    • G02B6/266Optical coupling means with optical elements between opposed fibre ends which perform a function other than beam splitting the optical element being an attenuator

Abstract

There is provided a multiport variable optical attenuation architecture (100), including a first optical signal manipulating means (105), to manipulate optical signals input thereto and output first manipulated optical signals; a second optical signal manipulating means (110) arranged to receive the first manipulated optical signals from the first optical manipulating means (105), and to adaptively manipulate the received first manipulated optical signals input thereto so as to output second manipulated optical signals; and a third optical signal manipulating means (120) arranged to receive the second manipulated optical signals, and to a predetermined manipulation of the second manipulated optical signals so as to output an attenuated signal.

Description

Description A MULTIPORT VARIABLE OPTICAL ATTENUATOR ARCHITECTURE, AND PARTS THEREOF BACKGROUND OF THE INVENTION

[1] The present invention relates to optical attenuator architecture for performing high- resolution variable optical attenuation of a wide range of optical wavelengths.

[2] Preferred embodiments of the present invention have particular, although not exclusive, utility in intelligent optical networks, optical measuring instruments, fiber- array-based systems, photonic signal processors, current sensing, dense optical computers, and displays.

[3] Throughout the specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

[4] The following discussion of the background art is intended to facilitate an understanding of the present invention only. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge as at the priority date of the application.

[5] An ability to control attenuations of multiport optical systems is important for next- generation intelligent optical systems. Such optical systems include, but are not restricted to, telecommunications systems, cable television systems, local area networks (LANs), current sensors, and displays. Most existing multiport optical attenuators are limited to a few ports with most of the intelligence performed by discrete electronics on both sides of the optical link. Recently emerged intelligent optical systems have been devised that include, in certain instances, many nodes linked by a number of different optical links. Although this multiple optical linking can significantly increase the capacity and flexibility of these optical systems, a cost-effective, compact-size, reliable, and dense multiport optical attenuator architecture must be found to interface with such systems, which offers the stability requirements for future applications requiring higher channel numbers.

[6] Dynamic optical attenuation is a power management process where the power of an optical signal is arbitrarily attenuated. Precise variable optical attenuation enables dynamic attenuation change, which is crucial for many emerging applications. In an exceptional case, where optical signals propagate through an optical fiber array, it is advantageous to be able to arbitrarily attenuate those signals to generate a particular power profile. BRIEF SUMMARY OF THE INVENTION

[7] It is an object of the present invention to provide for improved optical attenuation of multiport optical links.

[8] In accordance with one aspect of the present invention, there is provided a multiport variable optical attenuation architecture, including a first optical signal manipulating means coupled to the input means, to manipulate optical signals input thereto and output first manipulated optical signals; a second optical signal manipulating means arranged to receive the first manipulated optical signals from the first optical manipulating means, and to adaptively manipulate the received first manipulated optical signals input thereto so as to output second manipulated optical signals; and a third optical signal manipulating means arranged to receive the second manipulated optical signals, and to a predetermined manipulation of the second manipulated optical signals so as to output an attenuated signal.

[9] Preferably, the first optical manipulating means comprises an optical waveguide array and polarizer means to manipulate the optical signals input thereto by filtering and polarising the same.

[10] Preferably, the first optical manipulating means is a photonic crystal fibre array adapted to maintain single mode operation with bandpass optical filtering.

[11] In particular, it may be a 2-D polarization maintaining, tapered photonic crystal fibre array that maintains light polarization, provides single mode operation with bandpass optical filtering, and concentrates the output optical powers into higher density and hence smooth spatial light non-uniformities. In this manner the numerical aperture of the fibres is increased, thus achieving a higher viewing angle in display applications.

[12] Preferably, the third optical signal manipulating means is an analyser film rotated 90 degrees to the polarizer means, so that said predetermined manipulation involves only passing light with a polarization that is perpendicular to the polarization of said first manipulated optical signals.

[13] Alternatively, the first optical signal manipulating means does not have a polarizer means integrated therewith, and instead discrete polarizer means may be arranged between the first and second optical signal manipulating means for polarizing individual signals generated by the first optical signal generating means prior to said second optical signal manipulating means receiving said first manipulated optical signals.

[14] Preferably, the second optical manipulating means includes a magneto-optical film.

[15] Preferably, the magneto-optical film is a Bi-YIG film.

[16] Preferably, the magneto-optical film is driven by an integrated switching circuit integrally formed therewith to adaptively manipulate the received first manipulated optical signals input thereto. [17] Preferably, the integrated switching circuit is etched within the film core or may alternatively be deposited on the film surface, to generate a 2-dimensional magnetic field profile. [18] Preferably, the integrated switching circuit includes a micro-coil array that generates arbitrary magnetic fields along the direction of propagation of the input optical signals to rotate the polarization of the optical signals. [19] Preferably, the architecture includes a permanent magnet disposed between the second and the third optical signal manipulating means that applies an additional permanent magnetic field to the magnetic field generated by the micro coil elements. The permanent magnetic field is parallel to the propagation direction of the input light. [20] Preferably, the first, second and third optical signal manipulating means are integrated to provide an integral structure. [21] In accordance with a second aspect of the present invention, there is provided a method for manipulating input optical signals to produce an attenuated output signal, including: [22] polarizing and filtering the input optical signals to produce a first manipulated optical signal; [23] arbitrarily rotating the polarizations of the first manipulated optical signals to produce a second manipulated optical signal; and [24] passing a variable fraction of the second manipulated optical signals depending upon the degree of rotation to provide the attenuated output signal. [25] Preferably, the method includes controlling currents fed through micro-coils to generate a magnetic field profile on said first manipulated optical signals, said magnetic field profile performing said arbitrary rotating; said rotating adjusting the amount of polarization of individual elements of the first manipulated optical signal to provide said second manipulated optical signals, and analysing the second manipulated optical signals so that a variable optical attenuation is achieved. [26] In this manner a cost-effective, hardware-compressed, basic and versatile variable optical attenuator array can be provided that can be used for dense multiport optical systems. BRIEF DESCRIPTION OF THE DRAWINGS [27] The best mode for carrying out the invention will now be described, by way of example only, with reference to the accompanying drawings, of which: [28] Figure 1 shows the layout of a preferred embodiment for the multiport variable optical attenuator architecture of the present invention; [29] Figure 2 shows a result of a method for depositing micro-coils on the surface of a magneto-optical film; [30] Figure 3 shows a result of a method for etching a 3 D coil structure within the core of a magneto-optical film; and

[31] Figure_4 shows a result of a method for depositing conductive materials into the etched 3 D coil shown in Figure 3 to realize a micro coil. DETAILED DESCRIPTION OF THE INVENTION

[32] The best mode for carrying out the invention is directed towards a dense multiport variable optical attenuator architecture for a photonic system. The attenuator architecture generally employs an optical waveguide array, a polarizer, an integrated polarization rotator array, and an analyser, that can dynamically be configured to perform high-resolution variable optical attenuation of a wide range of optical wavelengths.

[33] As shown in Figure 1 of the drawings, the multiport variable optical attenuator architecture 100 includes a first optical signal manipulating means in the form of a tapered polarization maintaining photonic crystal fibre array (TPMPCFA) 105 including a plurality of photonic crystal fibres 108, a second optical signal manipulating means in the form of a magneto-optical film 110 having a micro-coil array 115 integrally formed therewith, and a third optical signal manipulating means in the form of an analyzer 120.

[34] Input optical signals launched into the multiport variable optical attenuator ports are first polarized and spectrally filtered by the TPMPCFA 105 to produce first manipulated optical signals. The polarized first manipulated optical signals then pass through the magneto-optical film 110 where their polarizations are independently rotated by controlling the amount of electric current fed into the elements of the micro- coil array 115 to produce second manipulated optical signals. These currents generate a variable magnetic field parallel to the propagation direction of the optical signals. When the polarization direction of a polarization rotated optical signal is not aligned with the polarization direction of the analyzer 120, a fraction of the propagating optical signal is blocked by the analyzer 120, thus attenuating that optical signal.

[35] A permanent magnet 125 is provided in the form of a film formed on the surface of the second optical signal manipulating means to apply a constant magnetic field perpendicular to the magneto-optical film 110. The role of the permanent magnet 125 is to convert the magnetic domains inside the magneto-optical film 110 into a single domain, thus reducing the excess optical loss.

[36] The polarization directions of the TPMPCFA 105 and the analyzer 120 are usually perpendicular to each other when no polarization rotation is provided to the micro-coil array 115.

[37] Figure 2 shows a conductive planar micro-coil 205 deposited on the magneto-opti cal film 110. The material of the micro-coil 205 can be any conductive material such as copper or aluminium. [38] A micro-coil array can also be fabricated to have a low resistance and a large number of turns.

[39] This way of forming the micro-coil is generally adopted when the magneto-optical film is too thin for etching.

[40] Figure 3 shows the process for realising a micro-coil within the core of a magneto- optical film.

[41] First, a cylindrical groove 305, of depth equal to the depth of the magneto-optical film 110, is etched within the core of the magneto optical film 110, as shown in Figure 3.

[42] Second, a conductive material is deposited into the cylindrical groove 305 to realise the micro-coil 405, as shown in Figure 4.

[43] It should be noted that the groove can be realised by laser etching. Ultra-short pulsed lasers with pico- and femto-second pulse duration and high peak power can limit the heat affected zone and make the material removal process dominated by ablation thus achieving excellent etching accuracy in magneto-optical films.

[44] Thus, if the magneto-optical film is sufficiently thick, the etching technique described above is the preferred way of forming the micro-coil.

[45] It should be apparent from the above description of the best mode of performing the invention that by using a variable polarization rotator sandwiched between a polarizer and an analyser, a variable attenuation can be achieved. Furthermore, by using a fibre array for the input ports and an integrated variable polarization rotator array, one can realise a cost-effective, static, multi-port variable optical attenuator.

[46] The main advantages of the proposed device are:

[47] (l)it enables adaptive multiport optical attenuation which is vital for many emerging photonics systems,

[48] (2)it is compatible with future multiport parallel photonic signal processing,

[49] (3)it is a static device (no mechanically moving parts), therefore, it has a longer life time in comparison to mechanically tunable attenuators, and

[50] (4)it is cost-effective since all ports share an integrated variable polarization rotator array.

[51] It should be appreciated that the scope of the present invention is not limited by the best mode of the invention specifically described herein. Accordingly, other modes of the invention may be embodied incorporating adaptations and modifications to the specific embodiment described herein with respect to the best mode, without departing from the scope nor the spirit of the invention.

Claims

Claims
[1] A multiport variable optical attenuation architecture, comprising: a first optical signal manipulating means coupled to the input means, to manipulate optical signals input thereto and output first manipulated optical signals; a second optical signal manipulating means arranged to receive the first manipulated optical signals from the first optical manipulating means, and to adaptively manipulate the received first manipulated optical signals input thereto so as to output second manipulated optical signals; and a third optical signal manipulating means arranged to receive said second manipulated optical signals, and to a predetermined manipulation of the second manipulated optical signals so as to output an attenuated signal.
[2] The architecture of claim 1 wherein the first optical manipulating means comprises an optical waveguide array and polarizer means to manipulate the optical signals input thereto by filtering and polarising the same.
[3] The architecture of claim 1 wherein the first optical manipulating means is a photonic crystal fibre array adapted to maintain single mode operation with bandpass optical filtering.
[4] The architecture of claim 3 wherein said array includes a 2-D polarization maintaining, tapered photonic crystal fibre array that maintains light polarization, provides single mode operation with bandpass optical filtering, and concentrates the output optical powers into higher density and hence smooth spatial light non- uniformities wherein a numerical aperture of the fibres is increased.
[5] The architecture of claim 1 wherein the third optical signal manipulating means is an analyser film rotated 90 degrees to the polarizer means, so that said predetermined manipulation involves only passing light with a polarization that is perpendicular to the polarization of said first manipulated optical signals.
[6] Alternatively, the first optical signal manipulating means does not have a polarizer means integrated therewith, and instead discrete polarizer means may be arranged between the first and second optical signal manipulating means for polarizing individual signals generated by the first optical signal generating means prior to said second optical signal manipulating means receiving said first manipulated optical signals.
[7] The architecture of claim 1 wherein the second optical manipulating means includes a magneto-optical film.
[8] The architecture of claim 7 wherein the magneto-optical film is a Bi-YIG film.
[9] The architecture of claim 7 wherein the magneto-optical film is driven by an integrated switching circuit integrally formed therewith to adaptively manipulate the received first manipulated optical signals input thereto.
[10] The architecture of claim 9 wherein the integrated switching circuit is etched within the film core or may alternatively be deposited on the film surface, to generate a 2-dimensional magnetic field profile.
[11] The architecture of claim 9 wherein the integrated switching circuit includes a micro-coil array that generates arbitrary magnetic fields along the direction of propagation of the input optical signals to rotate the polarization of the optical signals.
[12] The architecture of claim 1 further comprising a permanent magnet disposed between the second and the third optical signal manipulating means that applies an additional permanent magnetic field to the magnetic field generated by the micro coil elements; wherein the permanent magnetic field is parallel to the propagation direction of the input light.
[13] The architecture of claim 1 wherein the first, second and third optical signal manipulating means are integrated to provide an integral structure.
[14] A method for manipulating input optical signals to produce an attenuated output signal, including: polarizing and filtering the input optical signals to produce a first manipulated optical signal; arbitrarily rotating the polarizations of the first manipulated optical signals to produce a second manipulated optical signal; and passing a variable fraction of the second manipulated optical signals depending upon the degree of rotation to provide the attenuated output signal.
[15] The method of claim 14 further comprising controlling currents fed through micro-coils to generate a magnetic field profile on said first manipulated optical signals, said magnetic field profile performing said arbitrary rotating; said rotating adjusting the amount of polarization of individual elements of the first manipulated optical signal to provide said second manipulated optical signals, and analysing the second manipulated optical signals so that a variable optical attenuation is achieved.
PCT/IB2005/051878 2004-06-09 2005-06-08 A multiport variable optical attenuator architecture, and parts thereof WO2005122479A2 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
AU2004903110 2004-06-09
AU2004903110A AU2004903110A0 (en) 2004-06-09 Multiport Variable Optical Attenuator Patent

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2007526653A JP4891905B2 (en) 2004-06-09 2005-06-08 Multi-port variable optical attenuator structure and its parts
CN 200580026878 CN101023382B (en) 2004-06-09 2005-06-08 A multiport variable optical attenuator architecture, and parts thereof
AU2005253316A AU2005253316B2 (en) 2004-06-09 2005-06-08 A multiport variable optical attenuator architecture, and parts thereof
EP05744701A EP1766445A4 (en) 2004-06-09 2005-06-08 A multiport variable optical attenuator architecture, and parts thereof

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WO2005122479A2 true WO2005122479A2 (en) 2005-12-22
WO2005122479A3 WO2005122479A3 (en) 2006-07-27

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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5999305A (en) 1997-10-20 1999-12-07 Fujitsu Limited Optical device which makes use of magneto-optical effect

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5521726A (en) 1994-08-26 1996-05-28 Alliedsignal Inc. Polarizer with an array of tapered waveguides
JP3667827B2 (en) * 1995-08-29 2005-07-06 富士通株式会社 Faraday rotator
JP3587302B2 (en) * 2000-06-21 2004-11-10 松下電器産業株式会社 Optical device using the photonic crystal manufacturing method and a photonic crystal
JP4521609B2 (en) * 2000-09-11 2010-08-11 ミネベア株式会社 Magneto-optical body and optical isolator using the magneto-optical body
JP4056726B2 (en) 2000-10-27 2008-03-05 松下電器産業株式会社 Optical signal transmission system and magneto-optic modulator used therefor
US6542647B2 (en) * 2000-10-27 2003-04-01 Matsushita Electric Industrial Co., Ltd. Optical signal transmission system and magneto-optical modulator designed to establish modulation over wide range for use in the same
WO2002083583A1 (en) * 2001-04-12 2002-10-24 Omniguide Communications High index-contrast fiber waveguides and applications
JP4330923B2 (en) * 2002-05-09 2009-09-16 パナソニック株式会社 Optical isolator integrated magneto-optical modulator, method for manufacturing the same, and optical communication system using the optical isolator integrated magneto-optical modulator
JP2004077617A (en) * 2002-08-12 2004-03-11 Tdk Corp Variable light attenuator with optical isolator function
US7133579B2 (en) * 2002-10-18 2006-11-07 The Governors Of The University Of Alberta High-speed magneto-optic modulator
CN2596384Y (en) 2002-12-26 2003-12-31 武汉光迅科技有限责任公司 High reliability liquid crystal array variable attenuator

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5999305A (en) 1997-10-20 1999-12-07 Fujitsu Limited Optical device which makes use of magneto-optical effect

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP1766445A2

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EP1766445A4 (en) 2009-07-29
JP2008502024A (en) 2008-01-24
CN101023382A (en) 2007-08-22
EP1766445A2 (en) 2007-03-28
KR20070054176A (en) 2007-05-28
CN101023382B (en) 2010-05-05
WO2005122479A3 (en) 2006-07-27
JP4891905B2 (en) 2012-03-07

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