CA2349029A1 - Integrated optical add-drop multiplexer (oadm) using optical waveguide mirrors and multiplexer/demultiplexer - Google Patents
Integrated optical add-drop multiplexer (oadm) using optical waveguide mirrors and multiplexer/demultiplexer Download PDFInfo
- Publication number
- CA2349029A1 CA2349029A1 CA002349029A CA2349029A CA2349029A1 CA 2349029 A1 CA2349029 A1 CA 2349029A1 CA 002349029 A CA002349029 A CA 002349029A CA 2349029 A CA2349029 A CA 2349029A CA 2349029 A1 CA2349029 A1 CA 2349029A1
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- Prior art keywords
- oadm
- multiplexer
- drop
- add
- demultiplexer
- 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.)
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- 230000003287 optical effect Effects 0.000 title claims abstract description 17
- 239000000835 fiber Substances 0.000 description 8
- 230000005693 optoelectronics Effects 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000004806 packaging method and process Methods 0.000 description 2
- 238000002310 reflectometry Methods 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- 235000012431 wafers Nutrition 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
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
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
- H04J14/0201—Add-and-drop multiplexing
- H04J14/0202—Arrangements therefor
- H04J14/021—Reconfigurable arrangements, e.g. reconfigurable optical add/drop multiplexers [ROADM] or tunable optical add/drop multiplexers [TOADM]
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
- H04J14/0201—Add-and-drop multiplexing
- H04J14/0202—Arrangements therefor
- H04J14/0213—Groups of channels or wave bands arrangements
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
- H04J14/0201—Add-and-drop multiplexing
- H04J14/0215—Architecture aspects
- H04J14/0217—Multi-degree architectures, e.g. having a connection degree greater than two
-
- 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
- G02B2006/12083—Constructional arrangements
- G02B2006/12104—Mirror; Reflectors or the like
-
- 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
- G02B2006/12145—Switch
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- Microelectronics & Electronic Packaging (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Integrated Circuits (AREA)
- Optical Communication System (AREA)
Abstract
An integrated optical arrangement including planar waveguide demultiplexers and waveguide mirrors on a single chip is used to fabricate an optical add-drop multiplexer.
Description
Integrated optical add-drop multiplexes (OADM) using optical waveguide mirrors and multiplexer/demultiplexer Background of the Invention Field of the Invention This invention relates to the field of photonics, and in particular to an integrated optical add-drop multiplexes (OADM) using optical waveguide mirrors and multiplexer/demultiplexer.
2. Description of Related Art Dropping and adding selected wavelength channels is an important routing function at a node in an optical telecommunications network based on wavelength division multiplexing (WDM). This capability is necessary for directing incoming signals to the correct downstream node or to users, and for adding signals coming upstream (e.g. from users) onto the network. Although adding and dropping signals on a single fixed wavelength channel is relatively simple, there is no simple manufacturable solution :Eor adding and dropping a number of different arbitrarily chosen channels using a single device.
Adding and dropping wavelength channels can always be carried on electronically by optoelectronic (OE) conversion of all signals to electrical form, sorting the signals electronically, and then retransrr~itting onto the next fibre span. The add-drop function can be done optically 1=or a single channel using a narrow band filter with a transmission notch at the drop wavelength, combined with two circulators arranged as in Figure 1. The incoming data stream passes through the first circulator and through the filter. the wavelength channel corresponding to the filter transmission resonance is transmitted through to the second circulator and directed to the drop port. The add signal is fed into the add port of this circulator and is directed back through i:he filter to be recombined with the remaining channels at the first circulator. 'the filter used in this configuration can be a multilayer dielectric or fibre Bragg grating (FBG) filter.Other schemes for adding and dropping channels using discrete demultiplexers, multiplexers and switching networks (for wavelength selectable OADM's) have been proposed. Such schemes, if irr~plemented, require a great deal of packaging of discrete components and connecting fibre.
Adding and dropping signals electronically by OE conversion is expensive, due to the large number of active components required (i.e. ITU grid high speed lasers, high speed photodetectors) as well as the electronic processing involved.
Therefore an all-optical solution which can be transparent to bit rate and data format is very attractive. The scheme shown in Figure 1 is practical only when the appropriate filter is available for the required add / drop channels. As network wavelength channel separation decreases to 50 GHz, it becomes more difficult to obtain filters with the required performance. If more than one channel is to be dropped, and the dropped channels are selected arbitrarily from the spectrum, unique custom notch or band filters are required for every configuration. In addition, the configuration in Figure 1 cannot be easily extended to a wavelength selectable OADM device,, except in the simplest case of shifting a single drop channel by temperature tuning the filter or FBG.
Finally schemes requiring the combination of large numbers of separate components connected by fibre jumpers involve enormous packaging and assembly costs.
Summary of the Invention This invention consists of a method for integrating optical planar waveguide demultiplexers and waveguide mirrors on a single chip to fabricate an optical add-drop multiplexes. The chip requires only one input/output fibre connection, and one add/drop fibre connection, independent o:E the number or arrangement of add/drop wavelength channels. The OADM can be implemented as a fixed channel passive device, or as an active programmable OADM if switchable mirrors (e.g. based on MEMS or other switching technology) are used.
In the invention a waveguide demultiplexer and multiplexes are connected by simple waveguide on a single chip. Each connecting waveguide incorporates a simple processing element that determines the wavelengths to be dropped and added.
Brief Description of the Drawings T'he invention will now be described in more detail, by way of example, only with reference to the accompanying drawings; in which:-Figure 1 shows a conventional filter based optical add/drop multiplexer; and Figure 2 shows an integrated add/drop multiplexer in accordance with the invenion.
Detailed Description of the Invention Figure 2 shows a schematic diagram of a device in accordance with the invention.
An optical signal consisting of many different wavelength channels is directed to the chip by an optical circulator A. The light is coupled from the fibre to the input guide B. The wavelength channels are separa~:ed out and directed into corresponding connecting waveguides D by an echelle grating C. In the fixed wavelength passive OADM case, the processing element can be a simple mirror E
that reflects the wavelength channels not dropped back to the input guide, and downstream through circulator A. The dropped wavelength channels pass through their respective connecting waveguides and are recombined onto the output waveguide G by the final echelle grating F. The output circulator directs the dropped channels to their destination, and at the same time directs the added channels into the device. Since the path of the add channels is exactly the reverse of the dropped channels, the add channels will pass through the chip unhindered and join the channels directed downstream by circulator A. In an active wavelength selectable OADM, the mirror E would be replaced by an switchable mirror which can either reflect the given wavelength channel back upstream, or allow it to pass unhindered into the drop stream. Such switching could be achieved using MEMs based mirrors or a cantilevered waveguides, or by any 1X2 switch where one arm terminates in a mirror while the other provides a through path to the drop output.
Adding and dropping wavelength channels can always be carried on electronically by optoelectronic (OE) conversion of all signals to electrical form, sorting the signals electronically, and then retransrr~itting onto the next fibre span. The add-drop function can be done optically 1=or a single channel using a narrow band filter with a transmission notch at the drop wavelength, combined with two circulators arranged as in Figure 1. The incoming data stream passes through the first circulator and through the filter. the wavelength channel corresponding to the filter transmission resonance is transmitted through to the second circulator and directed to the drop port. The add signal is fed into the add port of this circulator and is directed back through i:he filter to be recombined with the remaining channels at the first circulator. 'the filter used in this configuration can be a multilayer dielectric or fibre Bragg grating (FBG) filter.Other schemes for adding and dropping channels using discrete demultiplexers, multiplexers and switching networks (for wavelength selectable OADM's) have been proposed. Such schemes, if irr~plemented, require a great deal of packaging of discrete components and connecting fibre.
Adding and dropping signals electronically by OE conversion is expensive, due to the large number of active components required (i.e. ITU grid high speed lasers, high speed photodetectors) as well as the electronic processing involved.
Therefore an all-optical solution which can be transparent to bit rate and data format is very attractive. The scheme shown in Figure 1 is practical only when the appropriate filter is available for the required add / drop channels. As network wavelength channel separation decreases to 50 GHz, it becomes more difficult to obtain filters with the required performance. If more than one channel is to be dropped, and the dropped channels are selected arbitrarily from the spectrum, unique custom notch or band filters are required for every configuration. In addition, the configuration in Figure 1 cannot be easily extended to a wavelength selectable OADM device,, except in the simplest case of shifting a single drop channel by temperature tuning the filter or FBG.
Finally schemes requiring the combination of large numbers of separate components connected by fibre jumpers involve enormous packaging and assembly costs.
Summary of the Invention This invention consists of a method for integrating optical planar waveguide demultiplexers and waveguide mirrors on a single chip to fabricate an optical add-drop multiplexes. The chip requires only one input/output fibre connection, and one add/drop fibre connection, independent o:E the number or arrangement of add/drop wavelength channels. The OADM can be implemented as a fixed channel passive device, or as an active programmable OADM if switchable mirrors (e.g. based on MEMS or other switching technology) are used.
In the invention a waveguide demultiplexer and multiplexes are connected by simple waveguide on a single chip. Each connecting waveguide incorporates a simple processing element that determines the wavelengths to be dropped and added.
Brief Description of the Drawings T'he invention will now be described in more detail, by way of example, only with reference to the accompanying drawings; in which:-Figure 1 shows a conventional filter based optical add/drop multiplexer; and Figure 2 shows an integrated add/drop multiplexer in accordance with the invenion.
Detailed Description of the Invention Figure 2 shows a schematic diagram of a device in accordance with the invention.
An optical signal consisting of many different wavelength channels is directed to the chip by an optical circulator A. The light is coupled from the fibre to the input guide B. The wavelength channels are separa~:ed out and directed into corresponding connecting waveguides D by an echelle grating C. In the fixed wavelength passive OADM case, the processing element can be a simple mirror E
that reflects the wavelength channels not dropped back to the input guide, and downstream through circulator A. The dropped wavelength channels pass through their respective connecting waveguides and are recombined onto the output waveguide G by the final echelle grating F. The output circulator directs the dropped channels to their destination, and at the same time directs the added channels into the device. Since the path of the add channels is exactly the reverse of the dropped channels, the add channels will pass through the chip unhindered and join the channels directed downstream by circulator A. In an active wavelength selectable OADM, the mirror E would be replaced by an switchable mirror which can either reflect the given wavelength channel back upstream, or allow it to pass unhindered into the drop stream. Such switching could be achieved using MEMs based mirrors or a cantilevered waveguides, or by any 1X2 switch where one arm terminates in a mirror while the other provides a through path to the drop output.
The advantages of this OADM configuration are the reduction of required assembly. There are only two fibre to waveguide junctions required, for any number of add/drop channels. This will lead to an enormous reduction in assembled device cost. Separate optical circulators are required to separate the up and downstream paths, but connectorized circulators are readily available with very good performance at a small relative cost.
One overall layout would be the basis for an OADM for any number and arrangement of add drop wavelengths. For a passive waveguide OADM, the insertion of reflecting elements into the connecting waveguides could be done as a final customisable manufacturing step (this could be presented as a separate IP
under a different cover). This would allow rapid cu tomisation of OADM
components to customer requirements, while only maintaining an inventory of standardized OADM wafers.
.The channel spacing and density of this OADM configuration are set only by the demultiplexer. Given the present echelle grating technology, it should be scalable to 50 GHz, 80 channel systems and upwards. Any number and combination of wavelength channels can be programmed in as the add-drop channels.
Either an echelle grating based device, or an arrayed waveguide grating (AWG) device can be used as a waveguide based demultiplexer. The echelle demultiplexer is preferred since the demultiplexer footprint is much smaller than that for an AWG.
The passive OADM waveguide mirrors will requires vertical etches (to within one degree or less) in the material system used. High rejflectivity can be achieved using metal or multilayer dielectric coatings. In the case of high refractive index waveguides such as SOI, silicon oxynitride or InGaAsP, high reflectivity can be achieved by terminating the waveguides with right angle corner reflectors.
Total internal reflection at the waveguide/air interface should in theory give 100%
reflectivity. To achieve customisable OADM manufacturing, a mirror design should be used that can be implemented as a last step on pre-existing wafers.
One overall layout would be the basis for an OADM for any number and arrangement of add drop wavelengths. For a passive waveguide OADM, the insertion of reflecting elements into the connecting waveguides could be done as a final customisable manufacturing step (this could be presented as a separate IP
under a different cover). This would allow rapid cu tomisation of OADM
components to customer requirements, while only maintaining an inventory of standardized OADM wafers.
.The channel spacing and density of this OADM configuration are set only by the demultiplexer. Given the present echelle grating technology, it should be scalable to 50 GHz, 80 channel systems and upwards. Any number and combination of wavelength channels can be programmed in as the add-drop channels.
Either an echelle grating based device, or an arrayed waveguide grating (AWG) device can be used as a waveguide based demultiplexer. The echelle demultiplexer is preferred since the demultiplexer footprint is much smaller than that for an AWG.
The passive OADM waveguide mirrors will requires vertical etches (to within one degree or less) in the material system used. High rejflectivity can be achieved using metal or multilayer dielectric coatings. In the case of high refractive index waveguides such as SOI, silicon oxynitride or InGaAsP, high reflectivity can be achieved by terminating the waveguides with right angle corner reflectors.
Total internal reflection at the waveguide/air interface should in theory give 100%
reflectivity. To achieve customisable OADM manufacturing, a mirror design should be used that can be implemented as a last step on pre-existing wafers.
An active OADM will require switchable mirrors. This could be based on MEMS
technology, or any other 1x2 optical waveguide switch where one arm is terminated by a passive mirror and the other arm is a through connection.
This configuration of an integrated OADM is novel and brings with it important advantages noted above.
technology, or any other 1x2 optical waveguide switch where one arm is terminated by a passive mirror and the other arm is a through connection.
This configuration of an integrated OADM is novel and brings with it important advantages noted above.
Claims
1. An optical add-drop multiplexer comprising a planar waveguide demultiplexer and waveguide mirror integrated on a single chip.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002349029A CA2349029A1 (en) | 2001-05-28 | 2001-05-28 | Integrated optical add-drop multiplexer (oadm) using optical waveguide mirrors and multiplexer/demultiplexer |
| PCT/CA2002/000781 WO2002098038A1 (en) | 2001-05-28 | 2002-05-28 | Integrated optical add-drop multiplexer (oadm) using optical waveguide mirrors and multiplexer/demultiplexer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002349029A CA2349029A1 (en) | 2001-05-28 | 2001-05-28 | Integrated optical add-drop multiplexer (oadm) using optical waveguide mirrors and multiplexer/demultiplexer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2349029A1 true CA2349029A1 (en) | 2002-11-28 |
Family
ID=4169124
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002349029A Abandoned CA2349029A1 (en) | 2001-05-28 | 2001-05-28 | Integrated optical add-drop multiplexer (oadm) using optical waveguide mirrors and multiplexer/demultiplexer |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA2349029A1 (en) |
| WO (1) | WO2002098038A1 (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10173598A (en) * | 1996-12-09 | 1998-06-26 | Fujitsu Ltd | Optical multiplexing and demultiplexing device and optical transmission system using the device |
| US5959749A (en) * | 1998-05-20 | 1999-09-28 | Nortel Networks Corporation | Optical add/drop multiplexer/demultiplexer |
-
2001
- 2001-05-28 CA CA002349029A patent/CA2349029A1/en not_active Abandoned
-
2002
- 2002-05-28 WO PCT/CA2002/000781 patent/WO2002098038A1/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| WO2002098038A1 (en) | 2002-12-05 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |