EP0256075A1 - Demultiplexeur optique - Google Patents

Demultiplexeur optique

Info

Publication number
EP0256075A1
EP0256075A1 EP87901072A EP87901072A EP0256075A1 EP 0256075 A1 EP0256075 A1 EP 0256075A1 EP 87901072 A EP87901072 A EP 87901072A EP 87901072 A EP87901072 A EP 87901072A EP 0256075 A1 EP0256075 A1 EP 0256075A1
Authority
EP
European Patent Office
Prior art keywords
detector
light
detectors
schottky barrier
reflected
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Withdrawn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
EP87901072A
Other languages
German (de)
English (en)
Inventor
Craig Sawyers
Allen William Mabbitt
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.)
PA Consulting Services Ltd
Original Assignee
PA Consulting Services 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 claimed from GB868602309A external-priority patent/GB8602309D0/en
Application filed by PA Consulting Services Ltd filed Critical PA Consulting Services Ltd
Publication of EP0256075A1 publication Critical patent/EP0256075A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/0248—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies
    • H01L31/0352—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their shape or by the shapes, relative sizes or disposition of the semiconductor regions
    • H01L31/035272—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their shape or by the shapes, relative sizes or disposition of the semiconductor regions characterised by at least one potential jump barrier or surface barrier
    • H01L31/03529—Shape of the potential jump barrier or surface barrier
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0236—Special surface textures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0236—Special surface textures
    • H01L31/02363—Special surface textures of the semiconductor body itself, e.g. textured active layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/08—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors
    • H01L31/10—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors characterised by potential barriers, e.g. phototransistors
    • H01L31/101—Devices sensitive to infrared, visible or ultraviolet radiation
    • H01L31/102—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier
    • H01L31/108—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier the potential barrier being of the Schottky type

Definitions

  • This invention concerns optical demultiplexers by which light of one wavelength can be separated from light of another wavelength.
  • optical fibre communication systems In optical fibre communication systems, higher data transmission rates can be achieved by transmitting light signals at two differing wavelengths along the same optical path. Two preferred wavelengths for fibre optic transmission paths are 1.3 um and 1.55 um.
  • a detector which is capable of demultiplexing n light signals each having a different wavelength L1, L2 ?? Ln comprises a first
  • Schottky barrier detector the light receptive surface of which is profiled with a plurality of parallel grooves or ridges so that surface plasmon reson.ance will occur if light is incident therein and (n-1) further Schottky barrier detectors each having a light receptive surface wtiich is profiled in a similar manner to the first; projection means for projecting light containing all n signals onto the light receptive surface of a first of the detectors at an angle of incidence A1, such that surface plasmon resonance, and therefore absorption, will occur in respect of any component having a wavelength L1, all other components being reflected by the surface, and wherein a second one of the detectors is arranged to receive any light reflected by the first detector surface at an angle of incidence A2 such that surface plasmon resonance (and therfore absorption) will occur at the second detector in respect of any component having a wavelength L2, all other components being reflected by the surface, and each of the (n-2) remaining detectors is arranged to receive light
  • the condition for establishing surface plasmon resonance is related to the groove pitch A g , the light wavelength A j and the angle of incidence ⁇ by the equation (to first order) :- T
  • Em is the (complex) dielectric constant of the metal.
  • Em is nearly real, negative, and has modules much larger than unity (eg. silver, Em ⁇ 40 in the visible range).
  • the quantity (Em/Em+1)1/2 is very close to unity. Generally, therefore:-
  • two detectors are provided, one receptive of the light signal at an angle of incidence A1 such that any L1 component sets up surface plasmon resonance in the first detector surface and is therefore absorbed and detected, whilst all other wavelengths (including L2) are reflected, and a second detector positioned relative to the first so as to receive any light reflected from the first detector at an angle of incidence A2, such that any component of wavelength L2 is absorbed (and therefore detected) by the second detector.
  • Figure 1 is an enlarged cross section through a Schottky barrier detector having a profiled surface as required by the invention
  • Figure 2 illustrates graphically the variation of reflected energy with wavelength, for a given angle of incidence
  • Figure 3 illustrates diagramatically how two detectors can be arranged to provide for demultiplexing two signals L1 and L2.
  • a Schottky barrier detector is shown in part as being formed from n-type silicon (layer 10), and a thin metal layer 12, forming a receiving and reflecting surface 14.
  • the silicon is profiled so as to define a plurality of parallel grooves 16, 18 etc. separated by ridges 20, 22 etc..
  • a light beam 24 is shown incident on the surface 24 at an angle A. If the wavelength of the light in the beam 24 is varied in the range of wavelengths LA to LB then for a given spacing and depth of the grooves 16, 18 etc, a response curve of reflected energy against wavelength will be obtained as is shown in Figure 2. Here reflected power R is plotted against wavelength and it will be seen that at one particular wavelength, LF, the reflected energy is substantially zero. It is at this wavelength that surface plasmon resonance occurs, resulting in virtually 100% absorption of the light of that wavelength.
  • a similar response curve is obtained if, instead of varying wavelength, light of constant wavelength is projected onto a profiled surface at differing angles of incidence.
  • this fact is utilised to advantage in that the angle of incidence A1 is selected so that resonance (and therefore absorption) occurs at wavelength L1 at detector 26 leaving predominately L2 components to pass to detector 28. This is angled relative to 26 so that the angle of incidence A2 is such that resonance and absorption occur at wavelength L2 at the second detector.
  • the electrical output from detector 36 will thus be proportional to the L1 wavelength component and that from 28 will be proportional to the L2 wavelength component, in the input light beam 30.

Landscapes

  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

Détecteur, permettant de démultiplexer des signaux lumineux contenant des composantes (L1, L2) de longueurs d'ondes différentes, dans lequel plusieurs détecteurs de barrière Schottky (26, 28) ayant des surfaces à rainures parallèles reçoivent la lumière avec des angles d'incidence (A1, A2) tels que les composantes (L1) sont absorbées par une résonance de plasmon au niveau du détecteur de barrière Schottky (26) et les composantes (L2) sont absorbées de la même manière au niveau du détecteur de barrière Schottky (28).
EP87901072A 1986-01-30 1987-01-29 Demultiplexeur optique Withdrawn EP0256075A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB868602309A GB8602309D0 (en) 1986-01-30 1986-01-30 Optical memultiplexer
GB8602309 1986-01-30
GB8700322 1987-01-08
GB08700322A GB2186144A (en) 1986-01-30 1987-01-08 Optical demultiplexer

Publications (1)

Publication Number Publication Date
EP0256075A1 true EP0256075A1 (fr) 1988-02-24

Family

ID=26290297

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87901072A Withdrawn EP0256075A1 (fr) 1986-01-30 1987-01-29 Demultiplexeur optique

Country Status (2)

Country Link
EP (1) EP0256075A1 (fr)
WO (1) WO1987004862A1 (fr)

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1089932A (fr) * 1977-12-05 1980-11-18 Norman Toms Multiplexeur par repartition de longueurs d'ondes/demultiplexeur dans des systemes de communication par fibres optiques
FR2536911B1 (fr) * 1982-11-30 1987-09-18 Western Electric Co Photodetecteur

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8704862A1 *

Also Published As

Publication number Publication date
WO1987004862A1 (fr) 1987-08-13

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Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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17P Request for examination filed

Effective date: 19870923

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB NL

ITCL It: translation for ep claims filed

Representative=s name: RICCARDI SERGIO & CO.

STAA Information on the status of an ep patent application or granted ep patent

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18W Application withdrawn

Withdrawal date: 19900323

R18W Application withdrawn (corrected)

Effective date: 19900323

RIN1 Information on inventor provided before grant (corrected)

Inventor name: SAWYERS, CRAIG

Inventor name: MABBITT, ALLEN, WILLIAM