EP1546774A2 - Dispositifs de guidage thermo-actif plasmons-polaritons de surface longue portee - Google Patents

Dispositifs de guidage thermo-actif plasmons-polaritons de surface longue portee

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Publication number
EP1546774A2
EP1546774A2 EP03793609A EP03793609A EP1546774A2 EP 1546774 A2 EP1546774 A2 EP 1546774A2 EP 03793609 A EP03793609 A EP 03793609A EP 03793609 A EP03793609 A EP 03793609A EP 1546774 A2 EP1546774 A2 EP 1546774A2
Authority
EP
European Patent Office
Prior art keywords
cladding
core
stripe
waveguide section
core stripe
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.)
Withdrawn
Application number
EP03793609A
Other languages
German (de)
English (en)
Inventor
Sergey Bozhevolnyi
Thomas Nikolajsen
Bonni Kryger
Kristján LE SSON
Ildar Salakhutdinov
Thomas S Ndergaard
Peter M. W. Skovgaard
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.)
Micro Managed Photons AS
Original Assignee
Micro Managed Photons AS
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 Micro Managed Photons AS filed Critical Micro Managed Photons AS
Publication of EP1546774A2 publication Critical patent/EP1546774A2/fr
Withdrawn legal-status Critical Current

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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
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B6/122—Basic optical elements, e.g. light-guiding paths
    • G02B6/1226—Basic optical elements, e.g. light-guiding paths involving surface plasmon interaction
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y20/00—Nanooptics, e.g. quantum optics or photonic crystals
    • 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
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B6/126—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind using polarisation effects
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/011—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  in optical waveguides, not otherwise provided for in this subclass
    • G02F1/0115—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  in optical waveguides, not otherwise provided for in this subclass in optical fibres
    • G02F1/0118—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  in optical waveguides, not otherwise provided for in this subclass in optical fibres by controlling the evanescent coupling of light from a fibre into an active, e.g. electro-optic, overlay
    • 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
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B2006/12133—Functions
    • G02B2006/12142—Modulator
    • 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
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B2006/12133—Functions
    • G02B2006/12147—Coupler
    • 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
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B2006/12133—Functions
    • G02B2006/12159—Interferometer
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/0147—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on thermo-optic effects
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/21—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  by interference
    • G02F1/225—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  by interference in an optical waveguide structure
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/29—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the position or the direction of light beams, i.e. deflection
    • G02F1/31—Digital deflection, i.e. optical switching
    • G02F1/313—Digital deflection, i.e. optical switching in an optical waveguide structure
    • G02F1/3132—Digital deflection, i.e. optical switching in an optical waveguide structure of directional coupler type
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2203/00—Function characteristic
    • G02F2203/10—Function characteristic plasmon

Definitions

  • the present invention relates to guiding devices supporting propagation of long range surface plasmon poiaritons where the complex propagation constant of the guided long- range surface plasmon polariton mode(s) can be dynamically adjusted in at least one section of the device.
  • the guiding devices comprise a core stripe of e.g. metal embedded in a cladding such as a dielectric cladding.
  • the present invention relates to devices where the dynamic adjustment is obtained via dissipation of heat from the core stripe into the surrounding dielectric material.
  • the devices may be used in the construction of dynamic light guiding integrated components for optical telecommunication.
  • a surface plasmon polariton is a coupled state between an electromagnetic field and oscillating free electrons at the surface of a conducting medium.
  • Surface plasmon poiaritons can propagate along interfaces between layers of materials with the real part of the dielectric constant being of opposite sign, such as between a metal and a dielectric material.
  • Surface plasmon poiaritons are confined to the interface in the sense that the electromagnetic field associated with a surface plasmon polariton decays exponentially into both media from its maximum at the interface.
  • TIR total internal reflection
  • the complex propagation constant ⁇ of modes propagating in a long-range surface plasmon polariton channel guide may be changed so as to induce losses in the long-range surface plasmon poiaritons.
  • the phase of the modes may be changed. This may be done by controllably change the complex refractive index of a region of the cladding, e.g. by using an active material in the cladding.
  • thermo active waveguides where the thermo optical effect is achieved by placing a heating electrode adjacent to the channel guide (see WO 01/48521, Figure 47 and corresponding description).
  • the heating is performed by a heating electrode incorporated in the waveguide structure.
  • the heating electrode For the heating electrode to heat up the cladding close to the core, the heating electrode is positioned in the vicinity of the core. It is a disadvantage of these structures that the heating electrode will perturb any propagating long-range surface plasmon polariton mode in the metal core, mostly by causing its scattering and absorption. It is another disadvantage that the heating electrode, being positioned at one side of the metal core, heats the cladding between the heating electrode and the core much more than the cladding on the other side of the core.
  • This invention relates to a way of realising the thermo optical effect in long-range surface plasmon polariton (LR-SPP) waveguides by using the waveguide core itself, namely the metal stripe, as the heating element.
  • LR-SPP surface plasmon polariton
  • waveguide structures are heated from within outwards, whereas in the devices disclosed by the prior art, the structures are heated from the outside in.
  • This configuration has a number of advantages. First, it removes any perturbation of an adjacent heating electrode on the propagating LR-SPP mode in the waveguide core.
  • the SPP field decreases exponentially from the core-cladding interface, it is the refractive index of the cladding material(s) closest to the core that has the major effect on the propagation properties of the waveguide.
  • the maximum temperature increase induced by heating of the core coincides with the maximum of the electromagnetic field of the guided mode, ensuring thereby the maximum effect of the temperature change on the mode propagation constant.
  • the present invention provides a thermo-active waveguide section for guiding and/or modulating long range surface plasmon poiaritons (LR-SPPs), the LR-SPPs having at least a first frequency v 0 and a corresponding first wavelength ⁇ 0 , the device comprising a core stripe having a finite width w m and a thickness t m , the core stripe comprising one or more material(s) having complex dielectric constant(s) k ⁇ with a negative real part, Re(kj) ⁇ 0, in at least a first frequency range comprising the first frequency, - a cladding at least substantially embedding the core stripe, the cladding comprising one or more material(s) having complex dielectric constants k 2 with a positive real part, Re(k 2 ) > 0, in at least a second frequency range comprising the first frequency, the finite width w m , and the thickness t m being selected so that the core stripe defines the waveguide
  • the gist of the invention is that the core stripe, by receiving energy heating it, will heat abutting or adjacent cladding materials.
  • the heating of the core may lead to changes in refractive indexes of the cladding materials, which will in turn modulate the complex propagation constant(s) of the LR-SPP mode(s) guided by the thermo-active LR-SPP waveguide. This may be used to introduce a loss or a change in phase for the propagating LR-SPP mode.
  • thermo-active waveguide section will also be referred to simply as waveguide section or simply waveguide.
  • the core stripe will be referred to as the core, the stripe, metal core or metal stripe (without implying that the material must be a metal).
  • the term section is not meant to imply that a waveguide section must be separated from a neighbouring section, although this will often be the case.
  • the core stripe may be heated in different ways.
  • the cores stripe is heated by a current flowing in the core stripe.
  • the means for receiving energy comprises first and second electrically conducting connectors, each having terminal end parts for being connected to different terminals of a current supply, and - contacting end parts in electrical contact with different parts of the core stripe of the waveguide section so that a current supply connected to the terminal end parts will generate a current through at least part of the core stripe.
  • thermo-active waveguide section is incorporated in a device also comprising a current supply having at least a first and a second in/outputs in electrical connection with different parts of the core stripe of the thermo-active waveguide section.
  • the current supply is electrically connected to the core stripe via the first and second connectors, allowing the current supply to generate a current through at least part of the core stripe.
  • the current heating the core stripe is induced by a varying magnetic field.
  • the means for receiving energy comprises an electrically conducting, closed, induction loop or circuit for receiving magnetic energy.
  • i B k ⁇ d ⁇ B /dt.
  • the core stripe is heated by absorbing electromagnetic (EM) radiation.
  • the means for receiving energy comprise at least a part of the cladding which is at least substantially transparent to EM radiation having a second frequency, so that the core stripe can be irradiated by said EM radiation through the cladding.
  • the thermo-active waveguide section in incorporated in a device also comprising a source of EM radiation for emitting EM radiation of the second frequency.
  • controllable losses for the LR-SSP modes guided in the thermo-active waveguide section may be of interest to introduce controllable losses for the LR-SSP modes guided in the thermo-active waveguide section, e.g. when modulating a signal.
  • Such controllable losses can be introduced by reducing the symmetry in dielectric cladding layers with respect to the core, thereby destroying the symmetric polariton supermode forming the LR-SPP.
  • the LR-SPP propagation constant depends (among other things) on the refractive index of the cladding materials, realising different refractive indices above and below the core stripe will introduce the desired asymmetry. This may e.g. be obtained by choosing the cladding material(s) so that the asymmetry arises (or disappears) when the structure is heated.
  • a first region of the cladding above the core stripe comprises a material having a temperature dependent refractive index n ⁇ (T) and a second region of the cladding below the core stripe comprises a material having a temperature dependent refractive index n 2 (T), the materials being chosen so that nj(T) and n 2 (T) have different thermo-optic coefficients, dn;JdT ⁇ dn 2 /dT.
  • the thermal properties such as heat capacity, thermal conductivity or convection factor of a portion of the waveguide section lying above a first part of the core stripe is different from the thermal properties of a corresponding portion of the waveguide section lying below said first part of the core stripe.
  • the thermal properties may be the thermal properties of the cladding abutting the core stripe or it may be the bulk thermal properties of the waveguide section above/below the core stripe, including layers not in direct contact with the core stripe.
  • thermo-active waveguide section may be used in various components or devices, optical and electrical. Some of these applications will be briefly described in the following sections.
  • thermo-active waveguide section may be incorporated in a device for guiding and/or modulating LR-SPPs further comprising a source of electrical and/or magnetic and/or thermal and/or electromagnetic energy for supplying energy to the receiving means of the thermo-active waveguide section.
  • a source of electrical and/or magnetic and/or thermal and/or electromagnetic energy for supplying energy to the receiving means of the thermo-active waveguide section.
  • the source may e.g. be a source of heat in thermal contact with the core stripe.
  • LR-SPPs may be provided to a thermo-active waveguide section in several ways. Photons may be coupled to SPPs on the core-cladding interfaces by any method described in the prior art, such as grating couplers or simply by end coupling from an optical waveguide such as an optical fibre or a planar waveguide. In a preferred device of the present invention, the LR-SPPs may be provided to the thermo-active waveguide section directly from another LR-SPP waveguide.
  • thermo-active waveguide section according to the first aspect and another LR-SPP waveguide section positioned in continuation of, but electrically insulated from, the thermo-active waveguide section so that an LR-SPP mode can be coupled from the thermo-active waveguide section to the another LR-SPP waveguide section.
  • the another LR-SPP waveguide section may or may not be a thermo-active waveguide section.
  • the term - in continuation of - does not mean that the waveguide sections must lie along the same straight line.
  • the another waveguide section should be positioned so that the LR-SPP mode from the thermo active first waveguide section can couple to LR-SPP modes in the another waveguide section and vice versa.
  • thermo-active waveguide section according to the first aspect may be used as a phase modulating element in one or more arms of a Mach Zehnder interferometer. Also, the thermo-active waveguide section according to the first aspect may be used in digital optical switch or an in-line modulator.
  • the present invention provides a method for adjusting a propagation constant of a LR-SPP mode(s) in a LR-SPP waveguide comprising
  • the core stripe having a finite width w m and a thickness t m , the core stripe comprising one or more material(s) having complex dielectric constant(s) t with a negative real part, Re(kj) ⁇ 0, in at least a first frequency range comprising the first frequency,
  • the cladding comprising one or more material(s) having complex dielectric constants k 2 with a positive real part, Re(k 2 ) > 0, in at least a second frequency range comprising the first frequency, the finite width w m , and the thickness t m being selected so that the core stripe defines a first waveguide section supporting propagation of LR-SPPs in the cladding, the method comprising the step of adjusting a refractive index, n 2 (T), of at least part of the one or more cladding materials by adjusting a temperature of the core stripe.
  • the temperature of the core stripe may be adjusted using different methods, such as:
  • One or more methods may be applied at the same time.
  • the temperature of the core stripe is adjusted by propagating LR-SPPs in the core stripe.
  • Some LR-SPP modes experience significant losses that lead to heating of the core stripe and the surrounding cladding material(s).
  • the waveguide section is heated by a (pre- or pump) pulse preceding or co-propagating the pulse which is to experience the modulation.
  • the pre- or pump pulse may have another frequency, mode profile, power, etc. than the pulse to be modulated, enabling a larger absorption of the pre- or pump pulse in the waveguide.
  • both the thickness and the width of the core stripe may be varying at least along a part of the axis of the waveguide so as to change the modal properties of the waveguide along the axis of the waveguide.
  • the invention provides a waveguide section with electro-optic cladding materials to guide and/or modulate LR-SPPs having at least a first frequency modulate.
  • the waveguide section comprising
  • the core stripe having a finite width w m and a thickness t m , the core stripe comprising one or more material(s) having complex dielectric constant(s) k x with a negative real part, Refkj) ⁇ 0, in at least a first frequency range comprising the first frequency,
  • the present invention provides a waveguide section having cladding materials with intensity dependent refractive index to modulate or amplify LR-SPPs having at least a first frequency v 0 and a corresponding first wavelength ⁇ 0 .
  • the waveguide section comprising a core stripe having a finite width w m and a thickness t m , the core stripe comprising one or more material(s) having complex dielectric constant(s) kj with a negative real part, Re(k ⁇ ) ⁇ 0, in at least a first frequency range comprising the first frequency, - a cladding at least substantially embedding the core stripe, the cladding comprising one or more material(s) having complex dielectric constants k 2 with a positive real part, Re(k 2 ) > 0, in at least a second frequency range comprising the first frequency, the finite width w m , and the thickness t m being selected so that the core stripe defines a first waveguide section supporting propagation of the long range surface plasmon polariton (LR-SPP) in the cladding, wherein at least a first region of the cladding and/or at least a second region of the cladding comprise(s) a material having an intensity dependent refr
  • the intensity dependence of the refractive index may be a third order non-linearity and materials having a strong third order non-linearity are often denoted ⁇ (3) - materials. These materials may be used in much the same way as electro-optic materials applying electromagnetic radiation instead of an electrical field. By pumping the ⁇ (3) - material optically, a change in the refractive index is induced so that the guiding properties of the LR-SPP waveguide are modulated.
  • ⁇ (3) - materials may comprise BaTi03, non-linear polymers, etc.
  • the pump light may be provided to the material having a refractive index n(I) from a top, bottom or side end of the device and/or the pump light may be guided along a LR-SPP waveguide.
  • At least a region of the cladding may comprise an optical non-linear material, so that propagation of LR-SPPs having frequencies ⁇ lr ⁇ 2 , etc. generates LR-SPPs having harmonic frequencies 2 ⁇ lr 2 ⁇ 2 , ⁇ 1 ⁇ ⁇ 2 , etc.
  • the invention provides a waveguide section for guiding and/or amplifying long range surface plasmon poiaritons having at least a first frequency v 0 and a corresponding first wavelength ⁇ 0 , the device comprising
  • the core stripe having a finite width w m and a thickness t m , the core stripe comprising one or more material(s) having complex dielectric constant(s) k x with a negative real part, Re(k ⁇ 0, in at least a first frequency range comprising the first frequency, a cladding at least substantially embedding the core stripe, the cladding comprising one or more material(s) having complex dielectric constants k 2 with a positive real part, Re(k 2 ) > 0, in at least a second frequency range comprising the first frequency, the finite width w m , and the thickness t m being selected so that the core stripe defines a first waveguide section supporting propagation of the long range surface plasmon polariton (LR-SPP) in the cladding, wherein at least a part of the cladding comprises an active material, the active material being adapted to provide stimulated emission when pumped optically and/or electrically.
  • LR-SPP surface plasmon polar
  • the active material may be an active material adapted to provide stimulated emission when pumped either optically or electrically.
  • the active material is characterised as a material where inversion of population of a quantized system can be achieved between an excited state and a lower energy state. Inversion of population may be achieved by optically or electrically pumping. Pumping of the active material optically and/or electrically will induce a change in the complex refractive index of the material and thus also of the propagation constant for an LR-SPP propagating through the part of the guide comprising the active material, so that the LR-SPP is amplified through that region.
  • the active material may comprise a semiconductor material or a combination of semiconductor materials selected from the group consisting of InP, GaAs, Ge, and Si. Also other semiconductor materials being adapted to provide stimulated emission when pumped either optically or electrically, such as GaAs, GaAlAs, GaAIAsP, etc. may be used. Alternatively, materials, such as glasses, polymers, ferroelectric crystals, etc. being doped with Neodymium, Erbium or other Lanthanides,
  • a region of active material may, thus, be provided, positioned in the cladding within the extent of the decaying electro magnetic fields and further at least two feedback elements may be provided around the active region.
  • Spontaneous emission captured by the LR-SPP waveguide may be amplified so as to provide laser action.
  • the region comprising the active material is positioned in proximity to the core stripe, or is positioned in the cladding within the extent of the decaying electromagnetic fields of the LR-SPPs guided by the LR-SPP waveguide. It is, furthermore, preferred to provide symmetrically positioned regions of active material so as to preserve the symmetrical mode profile of the LR-SPPs.
  • LR-SPPs propagating through the part of the guide comprising the active material and thus the population inverted region, induce stimulated emission and are thereby amplified. It is preferred that the frequency of the LR-SPP matches the frequency of a transition between the excited and lower energy state of the quantized system for the stimulated emission to take place.
  • spontaneous emission captured by the LR-SPP waveguide may be amplified so as to provide laser action.
  • the feedback elements may be any reflectors, such as mirrors, reflective coated end-facets, such as thin film coated end-facets, metal coated end-facet, etc., or gratings in the cladding
  • a waveguide laser may be made without the complex processing involved in manufacturing an active TIR waveguiding core.
  • the invention provides a device for guiding long range surface plasmon poiaritons having at least a first frequency v 0 and a corresponding first wavelength ⁇ 0 is provided.
  • the device comprises
  • the core stripe having a finite width w m and a thickness t m , the core stripe comprising one or more material(s) having complex dielectric constant(s) ki with a negative real part, Re(kj) ⁇ 0, in at least a first frequency range comprising the first frequency, the core stripe being at least substantially defined in a first plane,
  • the cladding comprising one or more material(s) having complex dielectric constants k 2 with a positive real part, Re(k 2 ) > 0, in at least a second frequency range comprising the first frequency, the finite width w m , and the thickness t m being selected so that the core stripe defines a first waveguide supporting propagation of the long range surface plasmon polariton (LR- SPP) in the cladding, the device further comprising another type of waveguide being at least substantially defined in a second plane which is displaced and/or rotated in relation to the first plane, the at least two waveguides defining a three dimensional structure, and the at least two waveguides are being adapted to allow for controllable coupling of energy between modes guided by the at least one LR-SPP waveguide and the other type of waveguide along a predetermined length of the LR-SPP waveguide.
  • the first waveguide is formed in a layered structure, the layer holding the core stripe of the first waveguide being the first plane, the layer holding a core of the second waveguide being the second plane.
  • the second waveguide the second waveguide may approach the first waveguide from above or below, making the second plane non-parallel to the layers of the structure.
  • the second waveguide may e.g. comprise a metal core stripe which follows a slope formed by etching until it merges with or gets sufficiently close to the first waveguide.
  • the second plane will not be the plane defined by the width of e.g. a core stripe of the second waveguide. Rather, it will be the plane the core stripe intersects at all times even though it bends up and down.
  • the devices and components presented above may be integrated on a chip, such as a silicon substrate, comprising at least two optical components is provided, wherein the at least two components may be connected via an LR-SPP waveguide.
  • a chip such as a silicon substrate
  • the at least two components may be connected via an LR-SPP waveguide.
  • LR-SPP waveguides that may be bent.
  • at least one of the components on the chip may be any of the above described components.
  • the structures of the present invention may be fabricated according to the following method for manufacturing long range surface plasmon polariton waveguide.
  • the method comprises the steps of providing a substrate - applying at least a first cladding layer comprising one or more material(s) having a complex dielectric constant(s) k 2 with a positive real part, Re(k 2 ) > 0, in at least one frequency range,
  • a core stripe comprising one or more material(s) having complex dielectric constant(s) k x with a negative real part, Re(k ⁇ ) ⁇ 0, in at least one frequency range, the core stripe having a finite width w m and a thickness t m on the at least first cladding layer,
  • At least a second cladding layer comprising one or more material(s) having a complex dielectric constant k 2 with a positive real part, Re(k 2 ) > 0, in at least another frequency range, so that the cladding layers are substantially embedding the core stripe, wherein the at least first and second frequency ranges comprise the first frequency, and wherein the finite width w m , and the thickness t m are selected so that the core stripe defines a waveguide supporting propagation of the long range surface plasmon polariton in the cladding.
  • the core stripe may be deposited by any metallization process, such as by physical vapour deposition, evaporation, sputtering, chemical vapour deposition, etc.
  • the cladding may be a spin-coated polymer, or the cladding may be a glass, such as a glass deposited by chemical vapour deposition.
  • a top cladding may either be grown or spun directly on the top of the first cladding layer or a top cladding may be bonded to the substrate comprising the first cladding and the core stripe.
  • Fig. 1A and B illustrate a thermo active optical waveguide according to the prior art.
  • Fig. 2A and B illustrate a thermo active LR-SPP waveguide according to the prior art.
  • Fig. 3A and B illustrate a thermo active LR-SPP waveguide according to the present invention.
  • Fig. 4A and B illustrate a thermo active LR-SPP waveguide according to the present invention where a current is used to heat the core stripe.
  • Fig. 5A and B show a device with a thermo active LR-SPP waveguide according to the present invention.
  • Fig. 6A and B illustrates different thermo active LR-SPP waveguide sections according to the present invention.
  • Fig. 7A-C show different configurations for crossings of LR-SPP waveguide sections.
  • Fig. 8 illustrates a method for making electrical connections to core stripes in a planar structure.
  • Fig. 9 illustrates a method for making several electrical connections to core stripes in a planar structure.
  • Fig. 10A and B show an inline modulator based on asymmetric thermal properties for thermo active LR-SPP waveguide sections according to the present invention.
  • Fig. 11A and B show different configurations for MZIs based on thermo active LR-SPP waveguide sections according to the present invention.
  • Fig. 12 shows an LR-SPP directional coupler based on thermo active LR-SPP waveguide sections according to the present invention.
  • Fig. 13A and B show different configurations for digital optical switches based on thermo active LR-SPP waveguide sections according to the present invention.
  • Fig. 14 illustrates a thermo active waveguide device where the core guide is modulated in a periodic way to create a reflective diffractive grating.
  • Fig. 15 shows an integrated device comprising components of the previous figures.
  • Fig. 16 illustrates the use of a preceding SPP pump pulse to heat op the core and adjacent cladding layers.
  • Fig. 17A and B show a waveguide section adapted to have a current induced in it by an external varying magnetic field.
  • Fig. 18 shows a thermo active LR-SPP waveguide section according to the present invention comprising a thermo-optic grating.
  • Fig. 19A and B show a MZI based on thermo active LR-SPP waveguide sections according to the present invention, used in experimental verification of the invention.
  • Fig. 20 is a graph showing the extinction ratio of the MZIs of Figure 19.
  • Fig. 21 is a graph showing the transient behaviour of the performance of the MZIs of Figure 19.
  • Fig. 22 is a graph showing the exponential rise/decay for determining the time constant of the transient behaviour illustrated in the graph of Figure 21.
  • Fig. 23 shows a digital optical switch based on thermo active LR-SPP waveguide sections according to the present invention used in experimental verification of the invention.
  • Fig. 24 is a graph showing the development of the intensity of arm I and arm II of the digital optical switch with a 6 mm long heating element of Figure 23.
  • Figure 25 shows the results of transmission through an in-line modulator having a 4 mm long heating element.
  • Fig. 26 shows an LR-SPP device comprising an electro-optic grating.
  • Fig. 27A and B are schematic drawings of LR-SPP devices based on ⁇ (3) materials.
  • Fig. 28 shows an LR-SPP device comprising a Mach-Zehnder modulator, modulation being introduced via by optical pumping.
  • Fig. 29A-C are schematic drawings of LR-SPP devices comprising active materials to achieve amplification and lasing properties.
  • Fig. 30 is a schematic drawing of an LR-SPP device comprising non-linear frequency conversion.
  • Fig. 31A-C are schematic drawings of multi layered waveguide structures incorporating LR- SPP guides.
  • Fig. ⁇ 32A and B show an example of a switching device incorporating optical fibres with LR- SPP waveguides.
  • Figs. 33A and B show dispersion relations for the propagation constant of a LR-SPP waveguide and for a standard single mode fibre and a dispersion compensated fibre, respectively.
  • Figure 1A and B show an example of a prior art thermo active optical waveguide section.
  • a cross section of the device perpendicular to the direction of propagation of the light is shown while on Figure IB the cross section is along the direction of propagation.
  • the device consists of a core of dielectric material 1 embedded into a cladding 2 consisting of another dielectric material with a lower refractive index.
  • a heating element 3 e.g. a metal electrode connected to a current supply.
  • the propagation constant of the modes sustained by the guide mainly depends on the refractive index of the core. When the heating element is heated, the temperature increase changes the effective refractive index of the guide and thus the propagation constant.
  • FIG. 2A and B shows an example of a thermo optic LR-SPP waveguide section.
  • the waveguide consist of a core metal stripe 4 surrounded by a top 5 and a bottom 6 cladding layer of substantially equal refractive index.
  • Such LR-SPP waveguides are described by the inventors in e.g. Applied Physics Letters 82, 668 (2003).
  • the propagation of LR-SPP modes in a LR-SPP waveguide can be characterised using a complex propagation constant ⁇ .
  • the electromagnetic field describing a LR-SPP mode in a given system can be expressed as:
  • E E(x, y) exp i( ⁇ z - ⁇ t) where the mode at frequency ⁇ propagates along the z-axis.
  • E(x,y) describes the amplitude of the field distribution perpendicular to the direction of propagation, while the amplitude evolution along the direction of propagation is described by ⁇ .
  • ⁇ ⁇ r + i ⁇ vine the field can be written as
  • E E(x, y) exp(-/7, z) ex i( ⁇ r z - ⁇ t) .
  • the complex propagation constants ⁇ of modes sustained by such a guide are dependent on the refractive indices of the core and the cladding, approaching, e.g., for the symmetric configuration and an exceedingly thin core the light wave number in the cladding.
  • the refractive index of a material is in general temperature dependent.
  • the propagation constants of the guide can be manipulated by providing thermal energy Q to the structure. In typical waveguide structures this is achieved by placing a heating element 3 on the outer boundary of the cladding where the element itself is not interacting with the electromagnetic field of the optical mode.
  • thermo optic LR-SPP devices In thermo optic LR-SPP devices according to the prior art, a heating element 3, e.g. a metal electrode connected to a current supply, is positioned above the cladding layer.
  • the propagation constant of the modes sustained by the guide mainly depends on the refractive index of the surrounding cladding layer.
  • the heating element When the heating element is heated, the temperature difference between the element 3 and the stripe 4 creates a thermal gradient in the intervening top cladding 5. The heating induces an asymmetry in the structure as the thereby manipulating the propagation constant of the bound LR-SPP modes.
  • the main idea of the present invention is to use the guiding metal core as a heating element, which dissipates heat into the surrounding dielectric material, this is illustrated in Figure 3A and B.
  • Figure 4A and B show a thermo active waveguide in which heating via the core metal stripe is obtained by sending an electrical current through the stripe.
  • A is the cross sectional area of the stripe. This level of resistance is sufficiently large as compared with the resistance of contacting wires, suggesting that that metal stripes with dimensions suitable for propagation of long range surface plasmon poiaritons, are also very suitable for conversion of electrical energy into heat.
  • Figure 5A and B show a sketch of a thermo active waveguide, according to Figure 4, seen from the top.
  • Figure 5A shows the whole structure while
  • Figure 5B shows a magnification of a section where contact is made.
  • Electrical contact to the guiding core stripe device is established via small contact stripes 7. The dimensions of these stripes are chosen in order to minimise the perturbation of the contact stripes 7 on the propagating LR-SPP mode in the core stripe 4.
  • the thickness of the contact stripes 7 is chosen to be the same as that of the core stripe 4 in order to limit the number of steps during processing.
  • the thickness t m of the core stripe is typically selected between 1-50 nm.
  • the contact stripes 7 are connected to wires 8, which are defined as any conductor with low resistance. In the devices manufactured, the wires 8 consist of thick (100 nm -300 nm) and wide (20 ⁇ m - 1 mm) metal stripes deposited in the same layer as the guiding core 4.
  • the current supply 20 for operating the device is connected to the wires 8.
  • the minimum separation, d, between the wire 8 and the guiding core 4, that is the length of contact stripe 7, should on one hand be chosen long enough (> 1 ⁇ m) to minimise the perturbation of the field in the wire 8 on the LR-SPP modes, and on the other hand short enough ( ⁇ lOO ⁇ m) to minimise heating and thereby heat dissipation by the contact stripes 7.
  • the width and thickness of contact stripe 7 should be chosen large enough to not create substantial ohmic heating of contact stripe 7, while small enough to not perturb (by scattering and absorption) the LR-SPP modes.
  • the length, d, of contact stripe 7 is preferably chosen to be longer than 1 ⁇ m, such as longer than 3 ⁇ m, 5 ⁇ m or 7 ⁇ m while shorter than 100 ⁇ m such as shorter than 50 ⁇ m or 20 ⁇ m.
  • the cross sectional dimensions, width and thickness, of contact stripe 7 is preferably the same as for the core stripe.
  • the width of the contact stripe 7 is selected between 1 ⁇ m and 100 ⁇ m, such as between 1 ⁇ m and 20 ⁇ m, such as between 1 ⁇ m and 12 ⁇ m, such as between 3 ⁇ m and 8 ⁇ m, narrower than 20 nm such as narrower than 10 nm, while wider than 3 nm such as wider than 5 nm.
  • the thickness of the contact stripe 7 is selected between 1 nm and 100 nm, such as between 1 nm and 50 nm, preferably between 1 and 15 nm, such as 10-50 nm.
  • the contact stripe 7 can be tapered, narrowing from the wire 8 towards the core stripe 4.
  • Figure 6A shows how to electrically insulate sections of the guiding core from each other to create thermo active waveguide sections 12. By introducing a small gap 9 the currents within each section can be controlled individually.
  • Figure 6B shows a magnification of the gap 9. The size (length) of the gap should be chosen taken the following considerations into account
  • the gap should electrically insulate two core stripe sections, and the precision of the fabrication technique sets a lower limit to how short the gap can be made so as to guarantee electrical insulation every time, also in a large scale production.
  • the lower limit is roughly 0,1 ⁇ m while a length of about 1 ⁇ m would give a safe insulation every time.
  • - Short circuit If the gap is too narrow as compared to the potential over it, the electric field strength in the intermediate dielectrica may become so large as to generate a disruptive discharge.
  • Capacitance If an alternating current is used, the gap may still become conductive in the sense of a capacitor. Hence, the effect capacitance of the gap should be estimated.
  • LR-SPP modes should couple between insulated sections with acceptable losses, such as below 1 dB or 10 dB.
  • Dividing the core stripes into sections by introducing small gaps 9 between them allows one to realise crossings 14, 15 and 22 of the core stripes 4, as shown in Figure 7A-C.
  • This ensures both very low optical cross talk (between modes propagating along crossed stripes) and electrical insulation.
  • an LR-SPP mode propagation along one of the directions will not be perturbed by the crossing guide if the crossing gap is sufficiently large (>5 ⁇ m) so as to eliminate overlap between the LR-SPP mode and the crossing core stripe.
  • the shaping of the core stripes 4 at the crossing can be altered in order to minimise optical cross talk as well as SPP coupling losses.
  • the configurations 14, 15 and 22 of Figures 7A-C are three possible embodiments, but many more can be envisaged.
  • Figure 8 illustrates how the possibility of sectioning the waveguides can be used to cross contact stripes with core guides. This possibility is convenient for the design of complex structures where several waveguides and wires are to be combined in a single plane.
  • Figure 9 illustrates a device for controlling two individual core stripes using only one electrical source. Especially a device like this can be used to design a device where exactly the same change in propagation constant of the two stripes is achieved with the same source. This will be the case if the two paths between the poles of the electrical source are identical.
  • Figure 10A and B shows the principle of an inline modulator 13 by which the loss of a LR- 5 SPP mode propagating through the stripe can be controlled by heating.
  • the principle of operation is, by heating of the core stripe 4, to break the symmetry of the refractive index distribution above and below the guiding stripe thereby inducing additional ohmic loss in the device 13. This can be done placing the top and bottom surface of the cladding layers 5 and 6 in contact with materials 101 and 102, e.g. air and silicon, with different thermal 10 properties such as heat capacitance, thermal conductivity or convection factor.
  • FIG 11A and B shows different configurations of Mach Zehnder Interferometers (MZI) 15 based on thermo active waveguide sections 13.
  • MZI Mach Zehnder Interferometers
  • An incoming electro magnetic wave is split into two branches by a Y-splitter 11.
  • Figure 12 shows an example of how a thermo active waveguide section 13 can be used to realise a directional coupler switch 16 by changing the propagation constant within the region of interaction between the two guides.
  • Figures 13A and B show two examples of digital optical switches 17 and 18 realised using the thermo active waveguide sections 13. Such devices are designed in such a way that light will follow the path of the highest refractive index. Different paths can therefore be configured using the thermo active waveguide sections.
  • Figure 14 illustrates a thermo active waveguide device 19 where the physical dimension of the core guide is modulated in a periodic way to create a reflective diffractive grating 10.
  • the variation of the dimension of the core guide can be either in the width, the thickness or both.
  • the grating is designed to reflect LR-SPP modes with specific propagation constants and allow other LR-SPP modes to pass.
  • the propagation constant of the propagating LR-SPP mode can be tuned in and out of resonance by adjusting the temperature by sending a current through the core guide.
  • the device 11119 can thereby work as an adjustable filter. For a suitable choice of period this can used to switch between conditions where the mode is completely or partially reflected or transmitted.
  • FIG 15 illustrates how most of the principles and component of the previous figures can be combined into an integrated device, which acts as a thermo active tuneable add/drop switch.
  • the first TO section decides if light is to proceed straight through the device or couple to the Mach Zehnder section of the device.
  • the arms of the Mach Zehnder device are configured with identical tunable gratings according to the sketch in Figure 14.
  • any light reflected by the grating will be dropped via the drop waveguide. Light which is not being reflected will continue and couple to output waveguides via the second directional coupler together with light added to the device via the add waveguide and reflected by the grating.
  • Figure 16 illustrates a thermo active guide section where heat dissipation by the core stripe is due to transformation of energy from a preceding LR-SPP mode into heat.
  • ⁇ 2 By propagating a SPP, ⁇ 2 , immediately before or together with the LR-SPP of interest, ⁇ _, will experience a structure heated by the absorption of ⁇ 2 .
  • ⁇ 2 can be chosen so as to have a much higher absorption than ⁇ r .
  • the pump pulse ⁇ 2 can thereby be used to switch the subsequent LR-SPP on or off depending on the initial conditions.
  • Figure 17A and B illustrates a thermo active guide section 23 where the heat dissipation by the core stripe is due to a current i B induced in the core stripe by an external varying magnetic field B.
  • the section 23 includes a closed conducting loop allowing generation of the current i B .
  • the induced current heats the core stripe 4 and the surrounding cladding materials 5 and 6 so as to generate a detectable change in the propagation constant of a bound LR-SPP mode, i.e. to increase or decrease the guided power.
  • the magnetic field B can be varying in space and/or time, whereby such a device can potentially be used as an all-optical magnetic flux sensor.
  • the cladding comprises a first cladding layer 32 having a refractive index n ⁇ T) and a second thermo-optic cladding layer 30 having a refractive index n 2 (T), the interface between the first and the second cladding layers being patterned to form a grating.
  • the grating may be adapted to controllably couple at least a part of the LR-SPP guided by the device out of the waveguide.
  • VOA Variable optical attenuation
  • MZI Mach-Zehnder interferometers
  • DOS Digital optical switches
  • the MZ interferometer is a basic component of integrated optics and in different configurations can be used for modulation, power control and even switching.
  • a MZI based on the splitting of the intensity of a LR-SPP guide into two separate arms has been fabricated to verify the performance of the present invention. As the two arms are again recombined into one, either using a Y-splitter or a directional coupler, the intensity coupled to the guide depends on the relative phase between the LR-SPP modes coming from the two arms. This phase sensitivity makes the device very sensitive to thermo optically induced refractive index changes introduced in one of the arms and thus very suitable for applications, which require low electrical power and fast response.
  • Digital optical switches are included in the verification study to provide a way for switching, which is less sensitive to the precision of the control power and which can act as a broadband device.
  • Digital optical switches in the simplest form consist of a Y-splitter with a shallow angle of separation between the two branches. If a refractive index difference is introduced between the two arms light will propagate along the path of the highest index.
  • in-line modulators are included in the verification study as these structures potentially provide a very simple way of providing a VOA, which is unique for the MMP wave guiding technology.
  • the operational principles of the in-line modulator are based on designing the waveguide in such a way that heating of the core creates a refractive index difference between the top and bottom cladding layers. The consideration prior to the design of the components was done with the aim of showing proof of principle of the device functionality. The designs where based on the following considerations.
  • thermo optical coefficient of the polymer used as cladding material (BenzoCycloButene from Dow Chemicals, BCB) has been reported to be
  • thermo optical coefficient of BCB Given the thermo optical coefficient of BCB an increase in temperature of the order of 3-4 degrees is therefore needed.
  • the aim of the verification study is to investigate the possibility of using metallic core stripes as heating elements.
  • the current needed in order to obtain the % phase shift in the MZI is of the order of 2-3 mA and the voltage for a 5,7 mm long heating element 1,4V.
  • the wires referred to are metal stripes with dimensions of a minimum of 50 nm thickness and 100 ⁇ m width. These stripes have a very low resistance of a few ohms per mm and are used to connect the contact pads (l x l mm 2 and at least 50 nm thick) with the heating elements.
  • the procedure for manufacturing the devices is basically the same as for the manufacturing of stripe waveguides.
  • the following recipe was used.
  • Resist coating AZ5214E 1.5 ⁇ m thickness/ UV exposure with mask 2/ development.
  • - Metal deposition 15 nm Au, deposition rate 2 A/s, followed by lift-off in an acetone bath with ultrasound.
  • Resist coating AZ5214E 2.2 ⁇ m thickness/exposure with mask 3/image reversal/ development.
  • - Metal deposition 3 nm Ti + 200 nm Au, deposition rate 10 A/s, followed by lift-off in an acetone bath (no ultrasound).
  • the contact pads in the intermediate plane was exposed by removing the top BCB layer. This was done primarily using a C0 2 -laser burning system.
  • the configuration of the Mach-Zehnder interferometer investigated in this study is shown in Figure 19A.
  • the length of the thermo active waveguide section 13 in one of the arms is 5,7 mm between the contact stripes 7.
  • Two different configurations of this device was investigated the difference between the two being the size of the gap inserted for electrical insulation of the arm from the rest of the structure, shown in Figure 19B (note that the same gap was introduced in both arms).
  • the distance between the arms was 250 ⁇ m.
  • the resistance of the arm was measured to be 1,6 k ⁇ for both devices.
  • Figure 20 shows a plot of ,a measurement aimed at determining the extinction ratio of the devices of Figure 19.
  • the output from the MZIs was recorded while changing the electrical current through the active arm and, hence, the power dissipated into the thermo active section. This way an extinction ratio better than 35 dB was achieved for the best device while the other device displayed a better than 25 dB extinction ratio.
  • the in-line modulators are added to this study as they potentially provide a conceptually simple way of controlling the loss of light propagating through the guide.
  • the principle of operation is, by heating, to break the symmetry of the refractive index distribution above and below the guiding stripe thereby inducing additional ohmic loss in the device.
  • Figure 25 shows the results of transmission through a waveguide with a thermo active waveguide section of 4mm length.
  • the bottom BCB surface is in contact with the Si wafer while the top surface is in contact with air, which makes the overall structure asymmetric.
  • the device shown in Figure 26 is an electro-optic device, wherein the top cladding comprises a cladding layer 32 having a refractive index n ⁇ which is not dependent upon the electric field E, and a part 30 comprising an electro-optic material having a field-dependent refractive index n 2 (E).
  • the interface between the two cladding materials is shaped to form a grating 31.
  • n 2 (E) ⁇ nj so that the grating 31 is turned on.
  • FIGS 27A and B examples of devices providing optical control of the properties of the LR-SPP waveguides 4 are shown.
  • the cladding material 33 comprises at least a region of materials having intensity dependent refractive indices n(I). These materials having a strong third order non-linearity are often denoted ⁇ (3) - materials.
  • ⁇ (3) - materials By pumping the ⁇ (3) - 5 material optically, a change in the refractive index is induced so that the guiding properties of the LR-SPP waveguides 4 are modulated.
  • an electromagnetic wave source 34 such as a light emitting diode is provided, whereby the intensity dependent refractive index in the part of the cladding 35 being illuminated by the light source 34 is changed so that propagation properties of the LR-SPP waveguide 4 are changed.
  • the pumping light 36 is guided along with a signal 37 in the LR-SPP waveguide, so that the, part of, the cladding layer having a refractive index dependent on the intensity will be changed.
  • a Mach-Zehnder modulator 38 based on a construction comprising ⁇ (3) -
  • the input arm 4 receives a LR-SPP signal 36 which is split into two arms 39 and 42 in splitter 41.
  • a pump beam 37 is provided by a waveguide 40 to the branch 39 in the area where the cladding comprises the ⁇ (3) - material.
  • the phase of the signal 36 in arm 39 are thus modulated by the signal 37 in
  • the waveguide 40 is here an LR-SPP waveguide, but it may be any other type of waveguide capable of coupling light into the Mach-Zehnder component by evanescent wave coupling.
  • the device can be constructed in such a way that the pumping light is totally coupled out of the Mach-Zehnder interferometer at the end of the region of evanescent wave coupling.
  • an active material may be provided in the cladding so as to obtain amplification and lasing by LR-SPP waveguides.
  • the cladding 51 comprises active materials for providing stimulated emission upon either electrical or optical pumping.
  • the stimulated emission in the active region of the cladding layers 51 amplifies an
  • FIG. 10C shows an example of an LR-SPP waveguide laser, wherein two feedback elements 53 and 54 are provided as coated end-facets of a waveguide sample.
  • spontaneous emission captured by the LR-SPP waveguide is amplified so as to provide laser action.
  • a laser beam having an output power P out may be generated.
  • a component comprising a 2.nd order non-linear material in the cladding 55 is shown. By providing electrical or optical pumping, as described above, such components may be used for frequency conversion, such as second harmonic generation or sum frequency generation.
  • Figure 31A, B and C show an example of stacked or layered structures comprising LR-SPP waveguides and/or other types of waveguides. Provided that the cores of the waveguides are in close proximity and provided that the propagation constants of two coupled modes in either waveguide are the same, the modes may couple from one plane to another.
  • a standard TIR waveguide having a core 60 is embedded in a cladding layer 61.
  • a core stripe 4 is deposited and a top cladding 62 is provided.
  • an electrode 63 is provided for electrical control of the coupling by tuning the coupling optimum frequency.
  • two core stripes 4 and 64 are embedded in cladding 62.
  • the distance between the stacked waveguides may be selected so as to allow for coupling between modes propagating in the two LR-SPP waveguides 4 and 64.
  • a LR-SPP waveguide 4 is deposited on top of a fibre 65.
  • a part of the fibre cladding is polished off and a core stripe 4 is deposited on the remaining polished cladding followed by deposition of a LR-SPP cladding 62.
  • the cladding is polished off so that the distance between the fibre core 67 and the core stripe 4 allows for coupling between the modes propagating in the fibre 65 and the LR-SPP waveguide 4.
  • An electrode 63 is provided to electrically control the coupling.
  • such stacked structures may comprise more than two layers, such as 3, 4 and 5 layers and even up to 10 or 15 layers. It is an advantage of such stacked structures that they are easy to manufacture, especially compared to stacked standard TIR waveguides, being a very cumbersome process.
  • an add/drop switch 71 based on a structure comprising stacked wave guides is shown.
  • the add/drop switch 71 is an example of a switching device incorporating optical fibres, such as single mode fibres or dispersion compensated fibres with LR-SPP waveguides. Light is coupled from one fibre to another via the LR-SPP guides. Light couples from the fibre to the LR-SPP guide only when the propagation constants are matched.
  • a number of fibres 71 are provided being embedded in a substrate 72 having a refractive index substantially equal to the refractive index of the fibre cladding. The substrate is prepared so as to remove part of the upper cladding of the fibres 71.
  • a LR-SPP waveguide core 4 is deposited as shown in Figure 31C.
  • the top cladding layer 73 comprises an electro-optic material so that the application of an electric field from electrode 63 can modulate the propagation properties (the propagation constant) of the LR-SPP guide.
  • the design shown comprises a number of LR-SPP to fibre couplers as shown in Figure 31C so as to be able to actively control the exchange of signal between the fibres.
  • the spectral width of the modes coupled from one waveguide to another is related to the difference in slopes of the dispersion curves for each of the waveguide.
  • the dispersion curve 75 for a standard TIR waveguide and the dispersion curve 76 for a LR-SPP waveguide is shown. It is seen that the slopes of the curves 75 and 76 are very similar around the point of intersection 77 where phase matching occurs.
  • the dispersion curve 76 for a LR-SPP is shown together with the dispersion curve 78 for a dispersion compensated fibre. It is seen that the slopes of the curves 76 and 78 are not similar around the point of intersection 79 where phase matching occurs.
  • the coupling between a dispersion compensated fibre and the LR-SPP waveguide may, thus, provide an increased spectral selectivity.

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Abstract

La présente invention concerne des guides d'ondes permettant de guider et de moduler des plasmons polaritons de surface longue portée (LR-SPPs). Les dispositifs de guidage comprennent une bande âme, par exemple, de métal d'une largeur finie enrobée d'un surfaçage tel qu'un placage diélectrique. Particulièrement dans les guides d'ondes selon l'invention, la constante de propagation complexe du/des mode(s) LR-SPP guidé(s) peu(ven)t être dynamiquement ajusté(s) par le chauffage de l'âme métallique, ce qui entraîne la dissipation de la chaleur dans le matériau diélectrique environnant. Ces dispositifs peuvent être utilisés dans la construction de composants intégrés guidant dynamiquement la lumière pour la télécommunicaiton optique.
EP03793609A 2002-09-06 2003-09-05 Dispositifs de guidage thermo-actif plasmons-polaritons de surface longue portee Withdrawn EP1546774A2 (fr)

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Cited By (1)

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Publication number Priority date Publication date Assignee Title
WO2011006250A1 (fr) * 2009-07-15 2011-01-20 James Stewart Aitchison Guide d’onde pour plasmon-polariton d’interface

Families Citing this family (7)

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Publication number Priority date Publication date Assignee Title
US7043134B2 (en) 1999-12-23 2006-05-09 Spectalis Corp. Thermo-optic plasmon-polariton devices
US8139283B2 (en) * 2007-11-09 2012-03-20 Alcatel Lucent Surface plasmon polariton modulation
CN102664350B (zh) * 2012-03-09 2014-06-11 中国科学院苏州纳米技术与纳米仿生研究所 一种等离子激元纳米激光器
CN105388563B (zh) * 2015-12-11 2019-01-25 江南大学 基于单层石墨烯片和环形谐振腔的表面等离子体马赫曾德尔干涉仪
US10996379B2 (en) 2017-04-07 2021-05-04 The Research Foundation for the State University New York Plasmonic phase modulator and method of modulating an SPP wave
JP2019191474A (ja) * 2018-04-27 2019-10-31 日本電気株式会社 接続構造及び波長可変レーザ
WO2020043299A1 (fr) * 2018-08-30 2020-03-05 Telefonaktiebolaget Lm Ericsson (Publ) Guide d'onde à cristal photonique

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6034809A (en) * 1998-03-26 2000-03-07 Verifier Technologies, Inc. Optical plasmon-wave structures
WO2001048521A1 (fr) * 1999-12-23 2001-07-05 University Of Ottawa Structures de guide d'ondes optique

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2004023177A2 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011006250A1 (fr) * 2009-07-15 2011-01-20 James Stewart Aitchison Guide d’onde pour plasmon-polariton d’interface

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