GB2395078A - Loss of light (LOL) indicator - Google Patents
Loss of light (LOL) indicator Download PDFInfo
- Publication number
- GB2395078A GB2395078A GB0225059A GB0225059A GB2395078A GB 2395078 A GB2395078 A GB 2395078A GB 0225059 A GB0225059 A GB 0225059A GB 0225059 A GB0225059 A GB 0225059A GB 2395078 A GB2395078 A GB 2395078A
- Authority
- GB
- United Kingdom
- Prior art keywords
- light
- optical
- loss
- switch
- optical switch
- 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- Withdrawn
Links
- 230000003287 optical effect Effects 0.000 claims abstract description 41
- 230000002238 attenuated effect Effects 0.000 claims abstract description 16
- 239000006185 dispersion Substances 0.000 claims abstract description 6
- 238000000034 method Methods 0.000 description 6
- 239000000835 fiber Substances 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000013307 optical fiber Substances 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000000758 substrate Substances 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
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/35—Optical coupling means having switching means
- G02B6/3586—Control or adjustment details, e.g. calibrating
- G02B6/3588—Control or adjustment details, e.g. calibrating of the processed beams, i.e. controlling during switching of orientation, alignment, or beam propagation properties such as intensity, size or shape
-
- 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
- G02B6/24—Coupling light guides
- G02B6/36—Mechanical coupling means
- G02B6/3628—Mechanical coupling means for mounting fibres to supporting carriers
- G02B6/3632—Mechanical coupling means for mounting fibres to supporting carriers characterised by the cross-sectional shape of the mechanical coupling means
- G02B6/3636—Mechanical coupling means for mounting fibres to supporting carriers characterised by the cross-sectional shape of the mechanical coupling means the mechanical coupling means being grooves
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
-
- 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
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/35—Optical coupling means having switching means
- G02B6/351—Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements
- G02B6/3512—Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements the optical element being reflective, e.g. mirror
-
- 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
- G02B6/24—Coupling light guides
- G02B6/36—Mechanical coupling means
- G02B6/3628—Mechanical coupling means for mounting fibres to supporting carriers
- G02B6/3648—Supporting carriers of a microbench type, i.e. with micromachined additional mechanical structures
- G02B6/3652—Supporting carriers of a microbench type, i.e. with micromachined additional mechanical structures the additional structures being prepositioning mounting areas, allowing only movement in one dimension, e.g. grooves, trenches or vias in the microbench surface, i.e. self aligning supporting carriers
-
- 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
- G02B6/24—Coupling light guides
- G02B6/36—Mechanical coupling means
- G02B6/3628—Mechanical coupling means for mounting fibres to supporting carriers
- G02B6/3684—Mechanical coupling means for mounting fibres to supporting carriers characterised by the manufacturing process of surface profiling of the supporting carrier
- G02B6/3692—Mechanical coupling means for mounting fibres to supporting carriers characterised by the manufacturing process of surface profiling of the supporting carrier with surface micromachining involving etching, e.g. wet or dry etching steps
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Micromachines (AREA)
Abstract
A loss of light (LOL) indicator for an optical network comprises a micro-electro-mechanical systems (MEMS) optical switch and a light detector. A light signal transmitted along a light path into the optical switch suffers attenuation in passing through the switch, e.g. through dispersion. The light detector is positioned such that the attenuated light is detected in order that a loss of light signal is generated if no light is detected, but with substantially no increase in the overall attenuation of the optical switch. In one embodiment incoming light is switched to output ports 10 using a mirror array and detector diodes 9 are distributed around the output ports to detect dispersed light. In an alternative embodiment diodes 12 are placed behind the mirror array 5 to detect light which has not been reflected by the mirror.
Description
1 2395078
LOSS OF LIGHT INDICATOR
This invention relates to a loss of light indicator for an optical network.
Some current optical transport systems make use of optical switches, such as Micro 5 Electro-Mechanical Systems (MEMS) technology, to switch light from one optical light path to another light path using micro mirrors. Due to light dispersion inside the optical switch these devices attenuate the optical signal passing through the switch. Conventionally, fault detection in optical fibres made use of the requirement to convert from an optical to an electrical signal at various points in the network. If the electrical conversion device received no signal, a loss-of 10 light state could he assumed and this could also be used to detect the position of a broken fibre.
However, transparent optical switches cannot detect certain faults, and in particular loss-of-light (LOL), without increasing the attenuation of the optical switch. Since there is no electrical conversion of the optical signal, it is not possible to detect loss-of-light without redirecting some of the light to a light detector. These light detectors can then be used to signal a LOL signal when 15 no light is present, however this technique increases the signal attenuation of the switch. The minimum attenuation introduced would be 0.2dB. Therefore the component cost for the optical switch would also be increased, due to the optical coupling device required to split the light path.
Some networks have electrical repeaters which could use the conventional techniques, but these are generally only every few hundred kilometres, so it is not possible to obtain an accurate 20 measure of where a break in the fibre has occurred.
In accordance with the present invention, a loss of light indicator for an optical network comprises an optical switch and light detecting means, wherein a light signal is transmitted along a light path in a network into the optical switch; wherein the light is attenuated in passing through the switch; wherein the light detecting means are 25 positioned such that the attenuated light is detected by the light detecting means; whereby a loss of light signal is generated if no light is detected, with substantially no increase in the attenuation of the optical switch.
The present invention can be used to detect light (or the lack of it) from inside an all optical switch in such a way as to leave the attenuation of the switch unchanged. It does this by 30 making use of the attenuated light trom within the switch. Light detectors are placed at appropriate points inside the optical switch to detect the attenuated light. These can then be used to generate a LuL Slllai WilCll Ilk' i;ght in bcills did.
:: The invention is applicable to any optical switch, but preferably, the optical switch is a micro electro mechanical systems (MEMS) optical switch.
Preferably, the light detecting means comprise photon defector diodes.
The photon detector diodes generate an electrical signal as photons impact on 5 them.
Generally, the attenuated light which is detected is light that has been attenuated by dispersion.
AIternatively, the light is attenuated by not being reflected by a mirror; and the light detecting means are positioned such that the attenuated light is detected after 10 passing through the mirror.
An example of a loss of light indicator according to the present invention will now be described with reference to the accompanying drawings in which: Figure I illustrates a MEMS optical switch with which a loss of light indicator according to the present invention can be used; 15 Figure 2 illustrates one example of a loss of light indicator according to the present invention for use in the switch of Fig. 1; Figure 3 illustrates a second example of a loss of light indicator according to the present invention for use in the switch of Fig. 1; and, Figure 4 shows in more detail an alternative construction for the indicator of Fig. 20 2. Fig. I a shows a diagram of a MEMS optical switch to which the present invention is particularly applicable. The switch I comprises a pair of optical fibre guides 2, 3 in which optical fibres 4, 6 are held. l,ight input to the switch through the optical fibres 4 is directed to a MEMS 25 mirror array 5. The incoming light is.switehed to an output port 10 by the mirror array 5 reflecting the light 8 into optical fibres 6 in the second optical fibre guide 3. Fig. Ib shows how some of the light is attenuated by dispersion 11 and falls outside a lens 7 which focuses the switched light into the output optical fibre 6.
In Fig. 2, an example of the present invention is illustrated in which photon detector 30 diodes 9 have been distributed around the output ports 10 in such a way as to make it possible to detect the dispersed light 11, and hence generate a loss of light (LOL) signal. Fig. 3 shows how the light input tron1 an optleal rlbre Is rellecicu try Tic IBM 5 gild lLc d;. )id light I 1;.-
deteeted in detectors 9 positioned outside the lens 7. MEMS devices used to create optical
( switches using mirrors attenuate the optical signal passing through the switch because of light dispersion inside the device. By using the light which is "lost" inside the switch, i.e. the dispersed light and adding photon detectors in the appropriate phaces in the switch, it is possible to detect and generate a Icss-of-light (LOL) alarm signal without increasing the all optical 5 switch's signal attenuation. There is only the attenuation which would normally occur due to the switching process. This is a significant improvement on prior art systems.
There rue other methods of detecting the attenuated light which could be used and these need not necessarily be placed around the output ports. One example is to detect light which has not been reflected by the mirror 5 (in the case that the mirror is not 100% reflective) by placing 10 detectors 12 behind the mirror. Similarly, the invention applies to other devices, such as a 3D MEMS device.
Fig. 4 shows an example of a technique of manufacturing the photon detectors 9 whereby a comb-like structure 13 is created which is placed next to the fibre guide 3. The comb-like structure would contain the photon detectors and the leaves of the comb would interleave with 15 the output ports 10. Another technique (not shown) would be to manufacture the photon detectors straight into the fibre guide material, although this may involve changing the current techniques for manufacturing the fibre guide. Generally, MEMS devices are made of silicon or other semiconductor material, so the guide can be manufactured as an etchable substrate and the detectors created by doping of some or all of the guide material, according to how limited an area 20 it was desired to measure the presence of light over.
Claims (6)
1. A loss of light indicator for an optical network, the indicator comprising an optical switch and light detecting means, wherein a light signal is transmitted along a 5 light path in a network into the optical switch; wherein the light is attenuated in passing through the switch; wherein the light detecting means are positioned such that the attenuated light is detected by the light detecting means; whereby a loss of light signal is generated if no light is detected, with substantially no increase in the attenuation of the optical switch
2. An indicator according to claim 1, wherein the optical switch is a micro electro mechanical systems (MEMS) optical switch.
3. An indicator according to claim I or claim 2, wherein the light detecting means 15 comprise photon detector diodes.
4. An indicator according to any preceding claim, wherein the detected light is light that has been attenuated by dispersion.
20
5. An indicator according to any of claims I to 3, wherein the light is attenuated by not being reflected by a mirror; and wherein the light detecting means are positioned such that the attenuated light is detected after passing through the mirror.
6. A loss of light indicator for an optical network as hereinbefore described with 25 reference to figures 2 to 4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0225059A GB2395078A (en) | 2002-10-29 | 2002-10-29 | Loss of light (LOL) indicator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0225059A GB2395078A (en) | 2002-10-29 | 2002-10-29 | Loss of light (LOL) indicator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB0225059D0 GB0225059D0 (en) | 2002-12-04 |
| GB2395078A true GB2395078A (en) | 2004-05-12 |
Family
ID=9946720
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0225059A Withdrawn GB2395078A (en) | 2002-10-29 | 2002-10-29 | Loss of light (LOL) indicator |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2395078A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114124212A (en) * | 2020-08-26 | 2022-03-01 | 华为技术有限公司 | Light splitting detector and optical fiber communication system |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6243511B1 (en) * | 1999-02-04 | 2001-06-05 | Optical Switch Corporation | System and method for determining the condition of an optical signal |
| US6243507B1 (en) * | 1999-06-07 | 2001-06-05 | At&T Corp. | Connection-verification in optical MEMS crossconnects via mirror-dither |
| US20020118909A1 (en) * | 2001-02-26 | 2002-08-29 | Alcatel | Signal monitoring in an optical cross-connect |
| US6493475B1 (en) * | 2000-10-19 | 2002-12-10 | Tellium, Inc. | Monolithic integration of signal-monitoring scheme in an optical switch |
-
2002
- 2002-10-29 GB GB0225059A patent/GB2395078A/en not_active Withdrawn
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6243511B1 (en) * | 1999-02-04 | 2001-06-05 | Optical Switch Corporation | System and method for determining the condition of an optical signal |
| US6243507B1 (en) * | 1999-06-07 | 2001-06-05 | At&T Corp. | Connection-verification in optical MEMS crossconnects via mirror-dither |
| US6493475B1 (en) * | 2000-10-19 | 2002-12-10 | Tellium, Inc. | Monolithic integration of signal-monitoring scheme in an optical switch |
| US20020118909A1 (en) * | 2001-02-26 | 2002-08-29 | Alcatel | Signal monitoring in an optical cross-connect |
Non-Patent Citations (1)
| Title |
|---|
| IEEE Photonics Technology Letters, Vol. 12, No. 7, July 2000, pages 885-887. * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114124212A (en) * | 2020-08-26 | 2022-03-01 | 华为技术有限公司 | Light splitting detector and optical fiber communication system |
| KR20230054718A (en) * | 2020-08-26 | 2023-04-25 | 후아웨이 테크놀러지 컴퍼니 리미티드 | Tap PD and fiber optic communication system |
| EP4195534A4 (en) * | 2020-08-26 | 2024-01-31 | Huawei Technologies Co., Ltd. | TAP-PD AND OPTICAL FIBER COMMUNICATION SYSTEM |
| KR102731988B1 (en) * | 2020-08-26 | 2024-11-20 | 후아웨이 테크놀러지 컴퍼니 리미티드 | Tap PD and optical fiber communication system |
| US12379554B2 (en) * | 2020-08-26 | 2025-08-05 | Huawei Technologies Co., Ltd. | Tap photodetector and optical fiber communication system |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0225059D0 (en) | 2002-12-04 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |