The invention relates to an optical network and to an optical network element.
The amount of data that has to be transported over long distances is continuously increasing. In the past, wavelength-division multiplexing, modulation formats providing increased spectral density and polarization-diversity have been successfully introduced in order to cope with this demand. Nowadays, enhancing the capacity of optical fibers by making use of mode multiplexing is under discussion.
Using different modes of an optical fiber for data communication leads in particular to the following problems:
As an alternative, the capacity may be increased by using several fibers within the same cable. This option makes use of the fact that modern cables contain up to around 1000 fibers and offers the advantage that these cables have already been deployed.
Hence,
The solution presented herein provides an alternative approach for efficiently conveying information via existing cables comprising several transmission fibers.
This problem is solved according to the features of the independent claims. Further embodiments result from the depending claims.
In order to overcome this problem, an optical network is provided comprising
Hence, the solution allows using legacy single mode fibers in combination with a multimode amplifier. This saves a significant amount of costs as a huge amount of single mode amplifiers are no longer required. The multimode amplifier may be an erbium-doped fiber amplifier.
In an embodiment, the first set of optical fibers and the second set of optical fibers comprise an identical number of optical fibers.
In another embodiment intended in particular for networks with optical switching functionality, the first set of optical fibers and the second set of optical fibers comprise different numbers of optical fibers.
In another embodiment, the first set of optical fibers and the second set of optical fibers each comprise singlemode optical fibers.
In a further embodiment, a singlemode optical amplifier is deployed between the first set of optical fibers and the multimode multiplexer and/or between the multimode demultiplexer and the second set of optical fibers.
Such additional singlemode amplifier preferably provides a limited (minor) gain and avoids or reduces noise.
In a next embodiment, the optical amplifier comprises at least one pump (in particular a laser source providing the required energy) comprising, e.g., a laser source (e.g., diode), that is coupled to at least one respective optical fiber of the first set of optical fibers or to at least one of the second set of optical fibers.
According to an embodiment, several singlemode optical amplifiers are deployed between the first set of optical fibers and the multimode multiplexer and/or between the multimode demultiplexer and the second set of optical fibers.
Pursuant to an embodiment, the several singlemode optical amplifiers work separately from each other and use separate pumps.
According to yet an embodiment, the several optical amplifiers, in particular a group of optical amplifiers, share(s) a common pump that is used to provide the required power to the different singlemode fibers.
It is in particular a solution that a group of amplifiers share a common pump and another group (at least one amplifier) is supplied by a different pump.
It is also an embodiment that the pump comprises a laser diode that emits light at a wavelength amounting substantially to 980 nm or to 1480 nm.
Pursuant to another embodiment, the pump is coupled to the respective optical fiber via a WDM coupler.
According to an embodiment, the pump is connected to a splitter, which is coupled to each of the optical fibers of the first set of optical fibers or to the second set of optical fibers.
According to another embodiment, an erbium doped fiber is deployed between the first set of optical fibers and the multimode multiplexer and/or between the multimode demultiplexer and the second set of optical fibers.
According to an embodiment, the singlemode optical amplifier comprises means to enable scattering effects, in particular stimulated Raman scattering or stimulated Brillouin scattering.
Hence, the amplification in the singlemode branches can be achieved by scattering effects such as stimulated Raman scattering or stimulated Brillouin scattering.
In a next embodiment, the singlemode optical amplifier provides parametric amplification.
In a further embodiment, the singlemode optical amplifier comprises a fiber doped with a rare earth element, in particular erbium.
Hence, a part of the singlemode branch is doped with a rare earth element, such as erbium, in order to provide amplification.
In yet another embodiment, the singlemode optical amplifier is implemented in the multimode multiplexer and/or in the multimode demultiplexer.
The problem stated above is also solved by an optical network element comprising
The embodiments described above with regard to the network apply to the network element accordingly.
Embodiments of the invention are shown and illustrated in the following figures:
It is assumed that a multimode amplifier exists that allows for simultaneous amplification of several modes (see, e.g., Y. Yung, et al.: First demonstration of multimode amplifier for spatial division multiplexed transmission systems, ECOC 2011, 978-1-55752-932-9/11).
Advantageously, this approach allows using existing fibers and combines them with a (preferably low cost) multimode amplifier.
As an alternative, amplifiers could be integrated into the multiplexing and demultiplexing units.
Number | Date | Country | Kind |
---|---|---|---|
12178480 | Jul 2012 | EP | regional |
The present application is a continuation application of U.S. patent application Ser. No. 14/401,622, filed Nov. 17, 2014. The invention described and claimed herein is also described in PCT/EP2013/064135, filed on Jul. 4, 2013, and EP 12178480.5, filed on Jul. 30, 2012. This European Patent Application, whose subject matter is incorporated here by reference, provides a basis for a claim of priority under 35 U.S.C. 119(a)-(d).
Number | Name | Date | Kind |
---|---|---|---|
5187759 | DiGiovanni | Feb 1993 | A |
5651080 | Chu | Jul 1997 | A |
5798853 | Watanabe | Aug 1998 | A |
9621297 | Cavaliere | Apr 2017 | B2 |
20020044324 | Hoshida | Apr 2002 | A1 |
20020048062 | Sakamoto | Apr 2002 | A1 |
20030072343 | Murray | Apr 2003 | A1 |
20030118299 | Seddon | Jun 2003 | A1 |
20030161030 | Oh | Aug 2003 | A1 |
20050105854 | Dong | May 2005 | A1 |
20060061855 | Sugaya | Mar 2006 | A1 |
20080138011 | Ramachandran | Jun 2008 | A1 |
20080170289 | Rice | Jul 2008 | A1 |
20080219299 | Lewis | Sep 2008 | A1 |
20090304322 | Davies | Dec 2009 | A1 |
20100111525 | Ford | May 2010 | A1 |
20100329671 | Essiambre | Dec 2010 | A1 |
20100329693 | Chen | Dec 2010 | A1 |
20120207470 | Djordjevic et al. | Aug 2012 | A1 |
20120219026 | Saracco | Aug 2012 | A1 |
20120224861 | Winzer | Sep 2012 | A1 |
20120262780 | Bai | Oct 2012 | A1 |
20140055843 | Roland | Feb 2014 | A1 |
20140286648 | Buelow | Sep 2014 | A1 |
20150171964 | Rapp | Jun 2015 | A1 |
20150188659 | Lipson | Jul 2015 | A1 |
Number | Date | Country |
---|---|---|
2333990 | Jun 2011 | EP |
2333990 | Jun 2011 | EP |
2365654 | Sep 2011 | EP |
2014019797 | Feb 2014 | WO |
Entry |
---|
Krummrich [“Spatial Multiplexing for High Capacity Transport” Optical Fiber Technology, 2011]. |
Bai, Neng et al., “Experimental Study on Multimode Fiber Amplifier Using Modal Reconfigurable Pump,” OFC/NFOEC Technical Digest, 3 pages (2012). |
Giles, C.R. et al., “Characterization of Erbium-Doped Fibers and Application to Modeling 980-nm and 1480-nm Pumped Amplifiers,” IEEE Photonics Technology Letters, vol. 3(4):363-365 (1991). |
International Search Report and Written Opinion for Application No. PCT/EP2013/064135, 12 pages, dated Oct. 22, 2013. |
Krummrich, Peter M., “Spatial multiplexing for high capacity transport,” Optical Fiber Technology, vol. 17:480-489 (2011). |
Nykolak, G. et al., “An Erbium-Doped Multimode Optical Fiber Amplifier,” IEEE Transactions Photonics Technology Letters, vol. 3(12):1079-1081 (1991). |
Riesen, Nicolas et al., “Few-Mode Elliptical-Core Fiber Data Transmission,” IEEE Photonics Technology Letters, vol. 24(5):344-346 (2012). |
Number | Date | Country | |
---|---|---|---|
20170331555 A1 | Nov 2017 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 14401622 | US | |
Child | 15606492 | US |