WO1998039676A1 - Polymeric phased array - Google Patents

Polymeric phased array Download PDF

Info

Publication number
WO1998039676A1
WO1998039676A1 PCT/EP1998/000544 EP9800544W WO9839676A1 WO 1998039676 A1 WO1998039676 A1 WO 1998039676A1 EP 9800544 W EP9800544 W EP 9800544W WO 9839676 A1 WO9839676 A1 WO 9839676A1
Authority
WO
WIPO (PCT)
Prior art keywords
waveguides
phased array
polymeric
coupler
optical
Prior art date
Application number
PCT/EP1998/000544
Other languages
French (fr)
Inventor
Tsjerk Hans Hoekstra
Original Assignee
Akzo Nobel N.V.
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 Akzo Nobel N.V. filed Critical Akzo Nobel N.V.
Priority to CA002289500A priority Critical patent/CA2289500A1/en
Priority to DE69804955T priority patent/DE69804955D1/en
Priority to EP98905385A priority patent/EP0975998B1/en
Priority to AU60988/98A priority patent/AU6098898A/en
Publication of WO1998039676A1 publication Critical patent/WO1998039676A1/en
Priority to US09/402,753 priority patent/US6377722B1/en

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—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
    • G02B6/12007—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 forming wavelength selective elements, e.g. multiplexer, demultiplexer
    • G02B6/12009—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 forming wavelength selective elements, e.g. multiplexer, demultiplexer comprising arrayed waveguide grating [AWG] devices, i.e. with a phased array of waveguides
    • G02B6/12011—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 forming wavelength selective elements, e.g. multiplexer, demultiplexer comprising arrayed waveguide grating [AWG] devices, i.e. with a phased array of waveguides characterised by the arrayed waveguides, e.g. comprising a filled groove in the array section
    • 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
    • G02B2006/12035—Materials
    • G02B2006/12069—Organic material

Definitions

  • the invention pertains to a polymeric phased array comprising an input coupler with N inputs and an output coupler with M outputs, N and M being natural numbers greater than or equal to 1 , wherein the couplers are optically connected by means of an optical array comprising a series of optical waveguides, each of which differs from a neighbour in optical path length by a predetermined fixed amount.
  • Phased arrays also denoted as, e.g, "Phasars,” “Array waveguide multiplexers,” or “Arrayed Waveguide Gratings,” manufactured of a polymeric material are known from, for instance, M.B.J. Diemeer et al., "Polymeric phased array wavelength multiplexer operating around 1550 nm,” Electronic Letters, 6th June 1996, Vol. 32, No. 12.
  • phased arrays i.e., phased arrays comprising a polymer core and at least one polymer (top) cladding
  • the polymeric phased arrays can be integrated with other (polymeric) optical components, such as switches, which allows the manufacture of add/drop multiplexers capable of individual routing of the different wavelength channels.
  • an interferometric device like the polymeric phasar is very sensitive to changes in temperature and physical ageing of the polymer of which it is manufactured.
  • the invention has for its object to reduce or even obviate the said sensitivity. This is achieved by a polymeric phased array as described in the first paragraph wherein the physical length of all the waveguides (in the array) is substantially equal.
  • the maximum deviation from the average (arithmetical mean) of the physical length of the waveguides is smaller than 5 percent, preferably smaller than 1 percent or even smaller than 0.5 percent, of the said average, because with such a small deviation the central wavelength is sufficiently fixed for practical use.
  • the waveguides run straight. Additional advantages of a phasar comprising straight and parallel waveguides are that such a phasar is compact, has a relatively low insertion loss due to the absence of bends in the waveguides, allows economic use of wafers, and allows a larger integration density. Also, the production of phasars is simplified because the phasars, which are densely packed on a single wafer, can be separated by means of a single and straight cut (as opposed to a complicated cut which manoeuvres between curved phasars) .
  • the straight phasar according to the present invention is even more compact when the input coupler and the output coupler are combined and the waveguides are provided with a mirror or a facet or endface that functions as a mirror.
  • This kind of waveguide can be manufactured, for instance, by simply dividing a straight phasar up into two equal parts (by means of a cut perpendicular to the waveguides of the array) and depositing a reflective coating or mounting a mirror on the obtained endfaces.
  • Phasars comprising combined couplers and a mirror surface are known in themselves, e.g., from H. Okayama et al., "Reflective Waveguide Array Demultiplexer in LiNn0 3 ,” Journal of lightwave technology, June 1996, Vol. 14, No. 6, pp. 985-990. From this publication it can be seen that prior art "half phasars require, besides the usual curved section, additional straight sections normal to the mirror surface in order to allow a mode confined in the waveguides to settle and avoid losses during reflection. Consequently, the half phasar of the prior art requires its own “custom made” manufacturing process, whereas the half phasars of the invention can, as mentioned above, be manufactured by dividing up an existing specimen.
  • the polymeric phased array is a so-called planar structure.
  • Free-space couplers are considered the most suitable couplers because of their wavelength independence.
  • Other preferred couplers are, e.g., Multi Mode Interferometers, also denoted as MMI couplers.
  • the optical path length of the waveguides is determined by the refractive indices and the lengths of the serial zones.
  • the waveguides may consist of, successively, a zone having a refractive index n*,, a zone having a refractive index n 2 , and a zone having, again, a refractive index n*,, with n 2 > n
  • the optical path length of each of the waveguides can be adjusted by varying the lengths of the different zones so as to form the required grating.
  • Waveguides comprising serial zones and one particular way of manufacturing them are described in more detail in T. Watanabe et al., "Novel 'serially grafted' connection between functional and passive polymer waveguides," Appl. Phys. Lett. 65 (10), 5 September 1995. Other ways of making waveguides with the said serial zones of course are not excluded.
  • At least one of the waveguides comprises a polymer which allows actively induced variation of the refractive index, for instance using the thermo-optical or electro-optical principle which is well-known to the skilled person.
  • the central wavelength and/or the wavelength peaks in the image plane in the output free-space coupler van be adjusted during operation by powering a heating element positioned near the waveguide.
  • a heating element it is preferred that at least some of the heating elements can be individually controlled.
  • EP 717 295 discloses a MxO multiplex/demultiplex device comprising optical fibres or silica waveguides which function as a grating.
  • waveguides of equal length are mentioned, it is apparent from the example illustrated by Figure 3 that equal is not to be taken literally, because evanescent coupling regions require the optical fibres to be in close contact, whereas in the grating area the optical fibres should be sufficiently far apart to avoid any interaction.
  • the physical lengths of the waveguides will vary considerably and are substantially unequal.
  • polymer waveguides are not mentioned and the underlying problems (sensitivity to both ageing and temperature variations) are not an issue in the devices according to EP 717 295, which document, consequently, has no bearing on the present invention.

Abstract

The invention pertains to a polymeric phased array comprising an input coupler with N inputs and an output coupler with M outputs, N and M being natural numbers greater than or equal to 1, wherein the couplers are optically connected by means of an optical array comprising a series of optical waveguides, each of which differs from its nearest neighbour in optical path length by a predetermined fixed amount, wherein the physical length of all the waveguides is substantially equal. The said phased arrays are less sensitive to changes in temperature and physical ageing.

Description

Polymeric phased array
The invention pertains to a polymeric phased array comprising an input coupler with N inputs and an output coupler with M outputs, N and M being natural numbers greater than or equal to 1 , wherein the couplers are optically connected by means of an optical array comprising a series of optical waveguides, each of which differs from a neighbour in optical path length by a predetermined fixed amount.
Phased arrays, also denoted as, e.g, "Phasars," "Array waveguide multiplexers," or "Arrayed Waveguide Gratings," manufactured of a polymeric material are known from, for instance, M.B.J. Diemeer et al., "Polymeric phased array wavelength multiplexer operating around 1550 nm," Electronic Letters, 6th June 1996, Vol. 32, No. 12.
This publication concerns phasars comprising curved waveguides of mutually differing physical lengths and mentions that polymeric phased arrays (i.e., phased arrays comprising a polymer core and at least one polymer (top) cladding) advantageously offer optical fibre compatibility combined with low cost and the possibility of using large substrates for the fabrication. Owing to the use of large substrates, the polymeric phased arrays can be integrated with other (polymeric) optical components, such as switches, which allows the manufacture of add/drop multiplexers capable of individual routing of the different wavelength channels.
However, an interferometric device like the polymeric phasar is very sensitive to changes in temperature and physical ageing of the polymer of which it is manufactured. The invention has for its object to reduce or even obviate the said sensitivity. This is achieved by a polymeric phased array as described in the first paragraph wherein the physical length of all the waveguides (in the array) is substantially equal.
It was found that, as a result of the substantially equal lengths of the waveguides, the phenomena discussed above influence the optical path lengths of all the waveguides to (substantially) the same extent. Consequently, the differences in optical path lengths of the waveguides, on which differences the operational principle of a phased array is based, remain virtually constant, and the functioning of the phased array is effectively unaffected.
It is preferred that the maximum deviation from the average (arithmetical mean) of the physical length of the waveguides is smaller than 5 percent, preferably smaller than 1 percent or even smaller than 0.5 percent, of the said average, because with such a small deviation the central wavelength is sufficiently fixed for practical use.
In a preferred embodiment of the polymeric phased array according to the present invention the waveguides run straight. Additional advantages of a phasar comprising straight and parallel waveguides are that such a phasar is compact, has a relatively low insertion loss due to the absence of bends in the waveguides, allows economic use of wafers, and allows a larger integration density. Also, the production of phasars is simplified because the phasars, which are densely packed on a single wafer, can be separated by means of a single and straight cut (as opposed to a complicated cut which manoeuvres between curved phasars) . The straight phasar according to the present invention is even more compact when the input coupler and the output coupler are combined and the waveguides are provided with a mirror or a facet or endface that functions as a mirror. This kind of waveguide can be manufactured, for instance, by simply dividing a straight phasar up into two equal parts (by means of a cut perpendicular to the waveguides of the array) and depositing a reflective coating or mounting a mirror on the obtained endfaces.
Phasars comprising combined couplers and a mirror surface are known in themselves, e.g., from H. Okayama et al., "Reflective Waveguide Array Demultiplexer in LiNn03," Journal of lightwave technology, June 1996, Vol. 14, No. 6, pp. 985-990. From this publication it can be seen that prior art "half phasars require, besides the usual curved section, additional straight sections normal to the mirror surface in order to allow a mode confined in the waveguides to settle and avoid losses during reflection. Consequently, the half phasar of the prior art requires its own "custom made" manufacturing process, whereas the half phasars of the invention can, as mentioned above, be manufactured by dividing up an existing specimen.
It is preferred that the polymeric phased array is a so-called planar structure. Free-space couplers are considered the most suitable couplers because of their wavelength independence. Other preferred couplers are, e.g., Multi Mode Interferometers, also denoted as MMI couplers.
One possible way of varying the optical path length of the waveguides whilst keeping their physical length constant consists in using different polymers having a refractive index which differs (by a predetermined fixed amount) for each of the waveguides in the array. Since this requires a large number of different (blends of) polymers and process steps, it is preferred that the waveguides comprise serial zones of different refractive indices. Thus, the optical path length of each of the waveguides is determined by the refractive indices and the lengths of the serial zones.
If a certain phasar comprises, for example, fifty waveguides of equal physical length but with the optical path length of each waveguide differing from that of its nearest neighbour(s) by a predetermined fixed amount, the waveguides may consist of, successively, a zone having a refractive index n*,, a zone having a refractive index n2, and a zone having, again, a refractive index n*,, with n2 > n By increasing the length of the zone having a refractive index n2, the optical path length is increased. Thus, the optical path length of each of the waveguides can be adjusted by varying the lengths of the different zones so as to form the required grating.
Waveguides comprising serial zones and one particular way of manufacturing them are described in more detail in T. Watanabe et al., "Novel 'serially grafted' connection between functional and passive polymer waveguides," Appl. Phys. Lett. 65 (10), 5 September 1995. Other ways of making waveguides with the said serial zones of course are not excluded.
In another embodiment according to the present invention at least one of the waveguides comprises a polymer which allows actively induced variation of the refractive index, for instance using the thermo-optical or electro-optical principle which is well-known to the skilled person.
By using such a polymer (either over the entire length of the waveguide or in one or more zones) the central wavelength and/or the wavelength peaks in the image plane in the output free-space coupler van be adjusted during operation by powering a heating element positioned near the waveguide. In the latter instance, it is preferred that at least some of the heating elements can be individually controlled.
It is noted that EP 717 295 discloses a MxO multiplex/demultiplex device comprising optical fibres or silica waveguides which function as a grating. Although waveguides of equal length are mentioned, it is apparent from the example illustrated by Figure 3 that equal is not to be taken literally, because evanescent coupling regions require the optical fibres to be in close contact, whereas in the grating area the optical fibres should be sufficiently far apart to avoid any interaction. To meet both these requirements, the physical lengths of the waveguides will vary considerably and are substantially unequal. At any rate, polymer waveguides are not mentioned and the underlying problems (sensitivity to both ageing and temperature variations) are not an issue in the devices according to EP 717 295, which document, consequently, has no bearing on the present invention.

Claims

Claims
1. Polymeric phased array comprising an input coupler with N inputs and an output coupler with M outputs, N and M being natural numbers greater than or equal to 1 , wherein the couplers are optically connected by means of an optical array comprising a series of optical waveguides, each of which differs from a neighbour in optical path length, characterised in that the physical length of all the waveguides in the array is substantially equal.
2. Polymeric phased array according to claim 1 , characterised in that the maximum deviation from the average physical length of the waveguides is smaller than 5 percent of the said average.
3. Polymeric phased array according to claim 1 or 2, characterised in that the waveguides run straight.
4. Polymeric phased array according to claim 3, characterised in that the input coupler and the output coupler are combined and at least one of the waveguides is provided with a mirror or a facet or endface that functions as a mirror.
5. Polymeric phased array according to any one of the preceding claims, characterised in that at least one coupler is a free-space coupler.
6. Polymeric phased array according to any one of the preceding claims, characterised in that at least one of the waveguides comprises at least two serial zones of different refractive indices. Polymeric phased array according to anyone of the preceding claims, characterised in that at least one of waveguides comprises a polymer which allows actively induced variation of the refractive index.
PCT/EP1998/000544 1997-03-03 1998-01-29 Polymeric phased array WO1998039676A1 (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
CA002289500A CA2289500A1 (en) 1997-03-03 1998-01-29 Polymeric phased array
DE69804955T DE69804955D1 (en) 1997-03-03 1998-01-29 Phasenarray aus polymer
EP98905385A EP0975998B1 (en) 1997-03-03 1998-01-29 Polymeric phased array
AU60988/98A AU6098898A (en) 1997-03-24 1998-01-29 Polymeric phased array
US09/402,753 US6377722B1 (en) 1997-03-03 1999-09-17 Polymeric phased array

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
EP97200614.2 1997-03-03
US4234597P 1997-03-24 1997-03-24
US60/042,345 1997-03-24

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US09/402,753 Continuation-In-Part US6377722B1 (en) 1997-03-03 1999-09-17 Polymeric phased array

Publications (1)

Publication Number Publication Date
WO1998039676A1 true WO1998039676A1 (en) 1998-09-11

Family

ID=21921375

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1998/000544 WO1998039676A1 (en) 1997-03-03 1998-01-29 Polymeric phased array

Country Status (2)

Country Link
AU (1) AU6098898A (en)
WO (1) WO1998039676A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2370128A (en) * 2000-12-12 2002-06-19 Kymata Ltd Arrayed waveguide grating with optical delay regions

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5212758A (en) * 1992-04-10 1993-05-18 At&T Bell Laboratories Planar lens and low order array multiplexer
EP0568236A2 (en) * 1992-04-29 1993-11-03 AT&T Corp. Efficient reflective optical multiplexers and demultiplexers
US5519796A (en) * 1995-03-06 1996-05-21 International Business Machines Corporation Gain equalization using monolithic planar waveguide grating multiplexer and demultiplexer
EP0717295A2 (en) * 1994-12-12 1996-06-19 Corning Incorporated MxO multiplex demultiplex component

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5212758A (en) * 1992-04-10 1993-05-18 At&T Bell Laboratories Planar lens and low order array multiplexer
EP0568236A2 (en) * 1992-04-29 1993-11-03 AT&T Corp. Efficient reflective optical multiplexers and demultiplexers
EP0717295A2 (en) * 1994-12-12 1996-06-19 Corning Incorporated MxO multiplex demultiplex component
US5519796A (en) * 1995-03-06 1996-05-21 International Business Machines Corporation Gain equalization using monolithic planar waveguide grating multiplexer and demultiplexer

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
BIERLEIN J D ET AL: "BALANCED PHASE MATCHING IN SEGMENTED KTIOPO4 WAVEGUIDES", APPLIED PHYSICS LETTERS, vol. 56, no. 18, 30 April 1990 (1990-04-30), pages 1725 - 1727, XP000209296 *
DIEMEER M B J ET AL: "POLYMERIC PHASED ARRAY WAVELENGTH MULTIPLEXER OPERATING AROUND 1550NM", ELECTRONICS LETTERS, vol. 32, no. 12, 6 June 1996 (1996-06-06), pages 1132/1133, XP000620719 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2370128A (en) * 2000-12-12 2002-06-19 Kymata Ltd Arrayed waveguide grating with optical delay regions

Also Published As

Publication number Publication date
AU6098898A (en) 1998-09-22

Similar Documents

Publication Publication Date Title
US6351581B1 (en) Optical add-drop multiplexer having an interferometer structure
EP1089098B1 (en) Athermal arrayed waveguide grating (AWG) multiplexer with polymer segment, and corresponding method of manufacturing
US5812709A (en) Optical device having switching function
US5745618A (en) Optical device having low insertion loss
US6256428B1 (en) Cascading of tunable optical filter elements
US6853769B2 (en) Arrayed waveguide grating with waveguides of unequal widths
EP2378330A1 (en) An optical filter or multiplexer/demultiplexer
Uetsuka AWG technologies for dense WDM applications
US6377722B1 (en) Polymeric phased array
EP1055143B1 (en) Cascading of tunable optical filter elements
US6587609B2 (en) Optical switching device and wavelength multiplexing device having planar waveguide-type structure
US7006729B2 (en) Optical components having reduced insertion loss
Smit Progress in AWG design and technology
Kaneko et al. Recent progress on arrayed waveguide gratings for DWDM applications
EP0975998B1 (en) Polymeric phased array
Clemens et al. Wavelength-adaptable optical phased array in SiO 2-Si
Koerkamp et al. Design and fabrication of a pigtailed thermo-optic 1× 2 switch
WO1998039676A1 (en) Polymeric phased array
US20060002653A1 (en) Apparatus for an optical circuit having a flat wavelength response
WO1999021038A1 (en) Phased array wavelength multiplexer
JPH11160555A (en) Optical wavelength multiplexer/demultiplexer
US20030198438A1 (en) Tunable add/drop multiplexer
Kokubun Waveguide filters and related technologies: issues and solutions for practical use in transmission systems
US11372157B2 (en) Integrated optical multiplexer / demultiplexer with thermal compensation
JPH05157920A (en) Waveguide diffraction grating

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AL AM AT AU AZ BA BB BG BR BY CA CH CN CU CZ DE DK EE ES FI GB GE GH GM GW HU ID IL IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT UA UG US UZ VN YU ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW SD SZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH DE DK ES FI FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA GN ML MR NE SN TD TG

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
WWE Wipo information: entry into national phase

Ref document number: 1998905385

Country of ref document: EP

ENP Entry into the national phase

Ref document number: 2289500

Country of ref document: CA

Ref country code: CA

Ref document number: 2289500

Kind code of ref document: A

Format of ref document f/p: F

REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

WWP Wipo information: published in national office

Ref document number: 1998905385

Country of ref document: EP

NENP Non-entry into the national phase

Ref country code: JP

Ref document number: 1998538091

Format of ref document f/p: F

WWG Wipo information: grant in national office

Ref document number: 1998905385

Country of ref document: EP