WO2002042801A9 - Systeme et procede permettant de transferer une quantite d'informations beaucoup plus importante dans des cables a fibres optiques en augmentant sensiblement le nombre de fibres par cable - Google Patents

Systeme et procede permettant de transferer une quantite d'informations beaucoup plus importante dans des cables a fibres optiques en augmentant sensiblement le nombre de fibres par cable

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Publication number
WO2002042801A9
WO2002042801A9 PCT/IL2001/001075 IL0101075W WO0242801A9 WO 2002042801 A9 WO2002042801 A9 WO 2002042801A9 IL 0101075 W IL0101075 W IL 0101075W WO 0242801 A9 WO0242801 A9 WO 0242801A9
Authority
WO
WIPO (PCT)
Prior art keywords
fibers
pipe
fiber
flat
cable
Prior art date
Application number
PCT/IL2001/001075
Other languages
English (en)
Other versions
WO2002042801A2 (fr
WO2002042801A3 (fr
Inventor
Yaron Mayer
Al J C Baur
Boris Dechovich
Original Assignee
Yaron Mayer
Al J C Baur
Boris Dechovich
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 IL13981000A external-priority patent/IL139810A0/xx
Application filed by Yaron Mayer, Al J C Baur, Boris Dechovich filed Critical Yaron Mayer
Priority to CA002428128A priority Critical patent/CA2428128A1/fr
Priority to GB0301155A priority patent/GB2379519B/en
Priority to AU2002220998A priority patent/AU2002220998A1/en
Publication of WO2002042801A2 publication Critical patent/WO2002042801A2/fr
Publication of WO2002042801A3 publication Critical patent/WO2002042801A3/fr
Priority to US10/307,422 priority patent/US20030174977A1/en
Publication of WO2002042801A9 publication Critical patent/WO2002042801A9/fr
Priority to US11/162,105 priority patent/US20070047885A1/en
Priority to US12/039,867 priority patent/US7899290B2/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
    • G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
    • G02B6/4401—Optical cables
    • G02B6/441—Optical cables built up from sub-bundles
    • G02B6/4411—Matrix structure
    • 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
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4204—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms
    • 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
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/2804—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers
    • G02B6/2852—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers using tapping light guides arranged sidewardly, e.g. in a non-parallel relationship with respect to the bus light guides (light extraction or launching through cladding, with or without surface discontinuities, bent structures)
    • 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
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4204—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms
    • G02B6/421—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms the intermediate optical component consisting of a short length of fibre, e.g. fibre stub
    • 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
    • G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
    • G02B6/4401—Optical cables
    • G02B6/4415—Cables for special applications
    • G02B6/4427—Pressure resistant cables, e.g. undersea cables
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/06—Construction or shape of active medium
    • H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
    • H01S3/067—Fibre lasers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/09—Processes or apparatus for excitation, e.g. pumping
    • H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
    • H01S3/094—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
    • H01S3/094003—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light the pumped medium being a fibre
    • H01S3/094019—Side pumped fibre, whereby pump light is coupled laterally into the fibre via an optical component like a prism, or a grating, or via V-groove coupling
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/23—Arrangements of two or more lasers not provided for in groups H01S3/02 - H01S3/22, e.g. tandem arrangements of separate active media
    • H01S3/2383—Parallel arrangements

Definitions

  • the present invention relates to broadband information transfer through optic fibers, and more specifically to a System and method for transferring much more information in optic fiber cables by significantly increasing the number of fibers per cable.
  • submarine cables each contain only 4-8 actual optic fiber pairs, or at most 16 pairs (in each pair one fiber typically transfers information in one direction and the other fiber in the other direction). This is a very small number and demonstrates some kind of myopia or fallacy in the "current wisdom" in this area.
  • the current wisdom seems to be laying each time a cable with just a few optic fiber pairs, and then laying a new cable each time it is used-up.
  • the present invention tries to achieve a large leap in thinking in this area by trying to explore dimensions that haven't been explored sufficiently by the "present wisdom".
  • the main embodiment of this concept discussed in this patent request is trying to transfer much more information in these cables by putting much more fibers per cable, such as for example even 1,000 or 10,000 times more than what is being done today.
  • One of the elements that seem to be most in need of improvement, is the number of fibers in each cable.
  • the materials themselves are not the only cost in laying such a cable. For example, the work involved typically costs at least about 15% of the entire operation. So putting much more fibers in each cable is actually even more cost-effective.
  • the substance the optic fiber itself is made of- silicon - is actually one of the cheapest and most available substances on earth, so as more and more such fibers are mass produced, their price will probably keep dropping even further.
  • the system includes also mechanisms for detecting malfunctions as soon as they occur and automatically assigning other fibers instead of the malfunctioning fibers.
  • Another solution is to hook up all of the fibers to an array of numbered sensors connected to a computer at each end of the cable and then let the two computers communicate and start testing automatically serially each fiber by sending a signal through it from one computer and registering on which sensor it came out at the other end.
  • the two computers can very quickly create a translation table that documents which element on each side corresponds to which element on the other side, but this is much less efficient.
  • a much better solution is to use multi-fiber flat jackets, as explained below (it is also possible to mark for example by separate colors or lines subsections on the jacket). Of course, various combinations of these solutions are also possible.
  • Another possible variation is to use at sea preferably an automatic fiber- welding machine that can weld two fibers as if they were made in one piece in the factory, although this is more expensive and will slow down the laying process by the time needed to "stitch" so many fibers, so for example if it takes the machine a whole month to weld 20,000 fibers, and 4 such breaks are needed, then it slows down the laying of the cable by 4 months. Also, such stitching might for example degrade a little the performance of some of the fibers, so this solution is less desirable (however, usually it is not more than 1 dB degradation).
  • Another solution is to use for example a water-proof protective shield of smaller external diameter so that much more cable can fit on each wheel, and then preferably add dynamically an external stronger shield which comes open and can be externally added to the cable from around it and be sealed automatically during the process of laying the cable.
  • Another solution is to use multi-fiber flat jackets with delta-type connectors that connect by pressure or by welding, as explained below. Of course, various combinations of these solutions are also possible.
  • Another problem is that if there are much more fibers within the pipe, there is more danger that they will be damaged by friction or stress or movement against each other for example when laying the cable.
  • each fiber is coated by a very thin layer of low friction plastic that preferably does not add more than 1 micron or at most a few microns to the fiber's size.
  • This coating is preferably with the same thermal expansion coefficient as glass, and can also be in different colors for groups of fibers, which is also good for the problem of identifying the fibers at both ends, but is preferably opaque and dark at least on the inside, to absorb escaping photons.
  • an anti-friction material is added into the pipe between the fibers, such as for example Talc powder or anti-friction gel.
  • Another possible variation is to put the fibers in larger groups into protective jackets, so that for example we can have about a 100 plastic jackets, each containing for example about 100-200 fibers.
  • Another possible variation is suspending the fibers within the pipe in a fluid with specific weight close to that of glass, so that they float freely in the fluid and have less friction.
  • this fluid is also dark and opaque to light, to avoid possible cross-talk between closely touching fibers.
  • Another possible variation is to give the fibers an electrostatic charge so that they repel each other and thus have less friction, however it may be difficult to create and maintain this charge. (It could be done for example by applying a high voltage to the fibers at certain intervals and also to an electrically insulating inner coating of the pipe, so that the fibers stay away from each other and from the inner border of the pipe, and also the fibers should be loose enough so as to move relatively freely in response to stress caused by bending of the pipe.
  • the electrostatic charge generated can be carried on to long distances and uses-up only a few watts.
  • the fibers can stay relatively close to each other, but avoid contact, since the closer they get, their repulsion increases).
  • thinner fibers so that for example, if we use 1 micron fibers instead of 10 micron fibers, they will have more room to move around the inner space of the pipe (however, this would require, of course, using shorter wavelengths for the signals, as explained below).
  • a flat cable so that for example we have a cable 20 centimeters or even 1 meters wide and for example 2 millimeters high (internally), and the fibers are lying relatively flat or completely flat across the width of the cable. Of course, many sizes are possible.
  • a multi- fiber flat, preferably flexible, jacket for the fibers (each containing for example 1000-2000 fibers), so that for example a number of such jackets can be stacked upon each other in the pipe and the pipe has one cell or a number of cells side by side, and preferably the fibers can move freely up and down within the flat jacket to compensate for stress caused by the bending of the pipe, and preferably also the flat jackets themselves can move similarly up and down within the pipe.
  • the flat jackets preferably have the same thermal expansion coefficient as glass.
  • Another variation is a preferably flexible, multi-layer, structure that fits preferably in a somewhat flattened pipe, and also allows each fiber to move freely up and down within its "mini-cell.”
  • Another variation is using for example one wide flat jacket for all the fibers and rolling it up within the pipe.
  • These various exemplary configurations are described in more detail in Figs. 12a-d.
  • These flat jackets or multi-layer jackets are preferably made of for example a plastic low friction material.
  • These flat jacket solutions and multi-layer solutions also make it much more convenient to identify the fibers at the two ends of the cable, and can also make it easier to create preferably modular group-connectors at the two ends of the cable.
  • this can also make it easy to create modular interfaces at the amplifiers, which can be used with the various solutions described for the amplifiers.
  • This can also help for example to keep the fibers away from each other at the amplifier in the solution of Fig. 10, by creating a small gap of fibers stripped from the jackets and putting the jackets at even distances from each other, so that the jackets on the two sides of the gap of bare fibers keep them in position, and the laser pump beam can hit all of them at the same time).
  • Another variation of the pipe that can be used with these flat jackets is for example a double pipe made of two (or more) hexagon-shaped pipes with a shared plane between them, or two (or more) round pipes welded together side by side.
  • each of the two (or more) cells should still be preferably wider than high, so that the width of the flat jacket is greater than the height of the cell, in order to make sure that the flat jackets always keep their correct orientation in relation to the pipe.
  • the pipes are still somewhat flattened, or they are round externally but somewhat flattened in their internal space. If the shapes of the 2 or more pipes remain round and not flattened internally, then one way of keeping the flat jackets in the correct orientation is for example to add an elongated square cell in the middle in which the flat jackets reside, and then the top and bottom remaining empty spaces can be used for example for electrical wires.
  • Fig. 14 This configuration is shown in Fig. 14.
  • Other variations in the shape of the pipe are also possible.
  • Another variation is to put one or more small dense bundle of fibers, each bundle preferably in one jacket, in the pipe, so that the bundles can move freely.
  • a bundle of a little more than 1mm in diameter can contain about 10,000 densely packed 10-micron fibers.
  • packing fibers together at distances of a few wavelengths of the light can cause cross-talk between the fibers.
  • another variation is to combine this with a very thin coating of flexible preferably opaque material (such as for example plastic, or nylon, or other polymer, or paint, or anodization of metals, etc.), over each fiber, which is preferably black or dark at least on the inside in order to absorb escaped photons and is preferably with the same thermal expansion coefficient as glass, or immersion in an opaque dark liquid or powder (such as for example fine carbon powder).
  • a coating is used, another variation is preferably to add also slight gaps in the coating or more than one coating material intermittently, preferably with slight gaps, to compensate for thermal expansion problems if the thermal coefficient is not close enough to that of glass.
  • This coating can be also on the outside at least partially marked with a different color for each sub-group of fibers.
  • sub-groups of fibers can be grouped for example into preferably very thin group-jackets within the larger jacket - for further strengthening and easier identification. This is less efficient than the flat jacket solution since there is no directional optimization, but it still might allow to use quite a large number of fibers. Of course, like with the flat jackets, this will work even better with thinner fibers, such a for example a few microns or 1 micron.
  • multi-fiber flat, preferably flexible, jackets are very different from the "current wisdom" types of optic-fiber jackets, and so are the multi-layer structures that are suggested, and also the for example the flattened metal pipe (with or without a division to inner cells) and the structure of 2 or more welded pipes, and the combination of flat jackets moving freely up and down only in the desired directions in the special pipes, which can bend only in the desired directions, are very different from the round pipes used by the "current wisdom".
  • various combinations of these solutions can also be used.
  • Raman Amplifier which works similarly to the Erbium amplifier, except that no Erbium impurity is needed in the fiber, so that it can work with ordinary optic fiber. It also uses a similar laser pump to boost the signal energy, but has the advantage that instead of a 100 nanometers range where Erbium is most sensitive (roughly between 1500 and 1600 nanometers), the Raman amplifier can work with a 200 nanometers range, and also unlike Erbium, which has this 100 nanometers band at a fixed position, the Raman amplifier can shift the 200 nanometers band to any position, so that a number of amplifiers can be used each with a 200 nanometers shift compared to the previous one, so altogether a much larger range can be used and therefore a larger number of lambdas can be used (since there is a minimum separation needed between each too adjacent wavelengths).
  • a combination of two or more lasers for example, since there are for example powerful Nd:YAG lasers available at 1064 nano and at also at 532 nano and 355 nano (by frequency multiplication), combining the light from both types and preferably filtering out the noises created by the combination, can create a laser of 1596 nano or 1419 respectively, or mixing it with other lasers of the visible spectrum (such as for example Helium-Cadmium lasers, which are typically available at 325-442 nano, Xenon-Fluoride lasers, which are typically available at 353-459 nano, or Argon lasers, which are typically available at 457-528 nano) can achieve other desired frequencies (however this has also a price of some reduction in the pump power).
  • grouped diode lasers some are available for example with powers of 50 up to 2000 watt, or quantum-cascade lasers, which can give high- efficiency in almost any desired frequency in the near infra-red range (750- 2600 nano) and mid infra-red.
  • quantum-cascade lasers Use for example interferometric wavelength converters, or a series of Raman amplifiers to shift the laser frequency higher in one or more steps by strongly amplifying each time a signal of longer wavelength with the laser pump, and then using the amplified signal as the new amplification pump.
  • the amplifier areas contain also appropriate transducers for converting the electrical power to the correct voltage needed for empowering the laser pump or pumps.
  • the metal shielded pipe of the cable is itself a bulky element, we can take advantage of it and make this problem part of the solution by using more than one layer of metal for this shield with good electrical isolation between them, so that part (or parts) of the metal pipe itself is used as both a strengthening shield and as electrical power lines.
  • the shield itself is made mostly of material with the same thermal expansion coefficient as glass, but since such alloys might not be the best electrical conductors, we might need to use for the electrical conducting layer materials with a different thermal expansion coefficient. Therefore, preferably these conducting layers are surrounded with flexible electrical isolators, such as for example sponge, so there is enough space to accommodate the different thermal behavior of these layers and for the fact that they can warm up more because of the electrical current.
  • these layers can also be made for example somewhat wavy or mesh-like (but still with a big mass) in order to compensate even better for this different thermal behavior. This can be done both in a round cable and in a flat cable.
  • the electrical wiring can also be inserted for example as an isolated layer within the support wall or walls that are between cells.
  • Corvis Corp. for example has accomplished this by using a combination of Distributed Raman amplifiers (which use the fiber itself as the gain medium, so the signal weakens much less over long distance) together with Soliton technology that gives the pulses a special shape that causes their shape to regenerate itself periodically automatically after certain distances.
  • Qtera (bought by Nortel), also uses a similar Soliton technology, together with Erbium amplifiers.
  • Xtera will use a combination of distributed and discrete Raman amplifiers. Marconi (bought by Cisco) has accomplished this, again, by Soliton technology.
  • Optimight is doing it by adding Code Division Multiplexing and using higher power lasers.
  • other solutions are improving Error corrections by better redundancy FEC (Forward Error-Correction) Codes, such as Ciena is doing.
  • Another solution is for example correcting the Polarity Mode Dispersion by DSP-controlled compensation upon entering the receiving end, as offered for example by Yafo and by Vitesse.
  • Another solution is fibers with better chromatic dispersion compensation (for example by dispersion slope matching) and/or using more precise lasers (for example by better filtering of each lambda).
  • Another solution can be optical filtering combined with the optical amplifiers, so that weakened distortions can be deleted. Of course, various combinations of these solutions will probably work even better.
  • Another solution is using for example ZBLAN fibers, which have much lower attenuation, as mentioned above, when they become cheaper.
  • Another solution shown by Alcatel is that if and when repeaters are eventually needed, the regeneration can be done optically for example by using SOA (Semiconductor Optical Amplifiers), such as a Mach-Zehnder interferometer for 2R regeneration (Reshaping) (because of its non-linear response) and two of these in a cascade for 3R regeneration (Reshaping & Retiming).
  • SOA semiconductor Optical Amplifiers
  • 2R regeneration Mach-Zehnder interferometer for 2R regeneration
  • 3R regeneration Reshaping & Retiming
  • One possible solution that might help lower the price of DWDM lasers and/or increase their accuracy is to use for example an optically diffractive prism, preferably with alternating opaque and transparent stripes, for optically splitting each laser to discrete sub-frequencies, and then preferably amplify each sub- frequency and modulate it on/off separately for example by using an integrated electro-absorptive modulator or Mach-Zehnder Modulator, or an external lithium niobate modulator.
  • This can convert each single less precise laser into a group of more precise lasers (in other words each laser can be used for creating a number of lambdas simultaneously), as shown in Fig. 15.
  • groups of fibers are coupled to multi-laser chips by using flat mutli-fiber jackets and connectors, as described in Figs. 12, 12a-b & 13a-c.
  • larger nanofibers for example those a few hundreds of nanometers thick
  • smaller ones especially nanofibers with the size of just a few nanometers
  • nanotechnology methods which means “from the bottom up” by adding molecules, instead of starting with larger structures and using relatively crude methods to press or corrode them into the required form.
  • These nanotechnologies will preferably also enable us to create small nano-lasers for creating the lambdas and for the pumps to power the amplifiers or at least make the interface for reaching each individual fiber at the two ends of the cable and at the amplifiers.
  • Another mid- way variation is to use for example fibers the size of 1-5 micron, and then we can have many more fibers in the same space than for example 10 micron fibers.
  • the system uses for example visible light at the range of 500 nanometers and below, or even UV, and Raman amplifiers are used instead of Erbium.
  • Another possible variation is to use (preferably together with DWDM), instead of many small fibers, a large number of thin optical wave-guides within a medium that supports them.
  • a medium that supports them.
  • submicron to nanometer range microstructures of waveguides can be created in Lithium Niobate (LiNb03) or other polymers, so instead of a large number of thin fibers, we can use a medium like this, which prevents the huge number of signals from mixing up by confining each channel to its own wave-guide. So this technology, which is currently used in optical switches, might be used also for broadband communications.
  • Another variation is using a large number of miniature long holograms that create a large number of small separate channels.
  • Another variation is to use some material, preferably a flexible light-reflective polymer, with a very large number of minute micro-tubes or nano-tubes of air or vacuum, so that each creates a separate channel for signals to travel through.
  • Some material preferably a flexible light-reflective polymer
  • a very large number of minute micro-tubes or nano-tubes of air or vacuum so that each creates a separate channel for signals to travel through.
  • multi- polarizations multiplexing which means using different polarizations for the channels so that more channels can exist in parallel.
  • the 80 or 100 lambdas are multiplied at least a number of times, so that within each group all the lambdas have the same polarization, and between the groups a different polarization is used for each group.
  • this solution requires polarization-retaining fibers, which are more expensive, and might suffer more from dispersion so it can be used either for much smaller distances or with some means of correcting the dispersion.
  • Fig. 1 is a schematic illustration of typical elements in a standard state of the art longdistance submarine or overland optic fiber cable.
  • Fig. 4 is a schematic illustration of an example of using multi-polarization multiplexing in each fiber (preferably in addition to DWDM).
  • Fig. 5 is a schematic illustration of an example of using an extremely large number of optic fibers in each cable (sub-marine or overland).
  • Fig. 6 is an illustration of a preferable way of using many small laser pumps for amplifying small groups of fibers or individual fibers.
  • Fig. 7 is an illustration of a preferable way of using a one-to-many optical splitter in the amplifier for conveying the energy from the laser pump to the individual fibers.
  • Fig. 8 is an illustration of a preferable way of using optical splitter(s) in the amplifier for conveying the energy from the laser pump to individual fibers spread flatly side by side.
  • Figs. 8a and 8b are 3-dimensional illustrative drawings of two preferable ways in which the splitter of figure 8 interfaces with the individual fibers.
  • Fig. 9 is an illustration of a preferable way of using optical means in the amplifier for conveying the energy from the laser pump to individual fibers spread side by side on the internal surface of the pipe.
  • Fig. 10 is an illustration of a preferable way of using optical means in the amplifier for conveying the energy from the laser pump to individual fibers spread more or less evenly in a transparent solid or liquid in the middle of the pipe in the area of the amplifiers.
  • Figs. 11a - l id show (through cross-sections) a few examples of some possible structures of a flat cable.
  • Fig. 12 which shows a 3-dimensional illustration of a preferable multi-fiber flat jacket.
  • Figs. 12a-c show a few examples of preferable configurations of the pipes that can be conveniently used with multi-fiber flat jackets.
  • Fig. 12d shows a preferable configuration of a multi-layer, preferably flexible, jacket within a preferably somewhat flattened pipe:
  • Figures 13a-b show an illustration of a few preferable types of connectors that can be conveniently used with the multi-fiber flat jacket, apart from the simple connector that is shown in Fig. 12.
  • Fig. 13c shows an example of two such connectors in the process of being coupled to each other.
  • Fig. 14 is an illustration of a preferable example of limiting the orientation of the flat jackets within a set of 2 (or more) welded together round pipes.
  • Fig. 15 is an illustration of a preferable example of lowering the price of DWDM lasers and/or increasing their accuracy by optically splitting each laser to discrete sub- frequencies, and then modulating each of them on/off separately.
  • electrical power line means either line or lines. Eventhough the invetion usually refers to the cable as a metal pipe, this is just an example and the pipe can be made also of other materials, such as for example strong plastic, carbon tubes, or various alloys.
  • the cable (1) is typically composed of a strong metal shield with a typical external diameter of 2.5-5 centimeters for submarine cables and much thinner for overland, and contains a small number of very thin fiber pairs (typically around 8-12 micron each, marked 2-5), and an electrical cable or cables (7) for powering the amplifiers (6) along the way.
  • the amplifiers (6) are typically about 10 meters long, and at their position the pipe is typically thicker than normal in order to accommodate the laser pumps and their interface, and they are typically at a distance of about 80-120 Kilometers between each other.
  • FIG. 4 we show an example of using 4 different polarizations in a single fiber (41), as viewed in a cross-section looking straight into the fiber.
  • Each straight line represents a plane in which the light waves of that polarization can travel.
  • using multiple polarizations at the same time allows the beam to take advantage of much more space in the fiber, compared to using just one polarization.
  • Each of the 4 exemplary polarized beams can contain multiple lambdas. Of course, a much lager number of polarizations can be used.
  • FIG. 5 we show a system similar to the system shown in Fig.l, with the optic fibers (52) and the electrical power line (57), except that much more fibers (52) are now being used in the cable (51) and the amplifiers (53) have to deal with a much larger number of fibers (52) simultaneously.
  • Fig. 6 we show an illustration of a preferable way of using many small laser pumps (for the sake of clarity, we show just 3 such laser pumps, marked 63-65) for amplifying small groups of fibers (62) within the cable (61), so that each pump for example handles just 3 fibers preferably through appropriate splitter interface.
  • the laser pumps are powered by the electrical power line (or lines) (67). These electrical power lines can also be actually inner isolated layers in the pipe itself.
  • the cable contains of course much more fibers than the example shows. Eventhough the illustration does not show it, preferably the pipe is actually much larger at the area of the amplifier, in order to accommodate the laser pumps and their interfaces.
  • these small laser pumps are typically semiconductor laser diodes, they can also be used one per each fiber. Another possible variation is to put for example thousands of such diodes within one or more chips, and have a very large number of fibers go through each chip so that preferably each fiber is interfaced with one mini laser pump.
  • the fibers are coupled to the chip by using flat mutli- fiber jackets and connectors, as described in Figs. 12a-b & 13a-c. It is also possible to use these small laser pumps with the fibers for example lying side by side (like in Fig. 8 below).
  • FIG. 7 we show an illustration of a preferable way of using one-to-many optical splitters in the amplifier for conveying the energy from one or more powerful laser pumps (71) to the individual fibers (74) that run through the cable (75).
  • one or more powerful laser pumps (71) is interfaced to the fibers that it empowers preferably by means of secondary fibers (73), each coupled at one end to one or more of the fibers that are (74) empowered by said laser pump and coupled at the other end preferably to the surface of a magnifying optical device (72) that widens the powerful laser beam (71) from the laser pump to the size of the surface needed for connecting all said secondary fibers (73) to the magnifying device surface (72).
  • This magnification makes the laser light spread to a larger area, while still maintaining its coherent properties.
  • some filters are also added in order to prevent possible reflections and therefore some cross-talk of signal echoes between the individual fibers (74).
  • the pipe is actually much larger at the area of the amplifier, in order to accommodate the laser pump (or pumps) and its interface. If more than one powerful laser pump is used, then preferably each pump handles a large sub-group of the fibers.
  • the coupling between each of the secondary fibers (73) to its appropriate data carrying fiber (74) is preferably done by a wavelength-selective optical coupler or by merging with the fiber at an appropriate angle.
  • the electrical power lines for the laser pump (77) are either electrical wires, or an inner isolated layer or layers in the pipe itself.
  • the cable's pipe (83) preferably extends to contain at least one wide flat surface (85), and the fibers (84) at the area of the amplifier are spread on this flat surface (85) side by side and coupled for example to a long optical splitter (82).
  • this splitter is made: For example, preferably a long semi-transparent strip of glass for example at a 45 degree angle is used, through which all the fibers pass, and the laser beam enters the glass from above, for example at a 90 degree angle to the fibers, and is projected from this glass directly into the length of the fibers. A large range of other angles could also be used.
  • Another variation is that the fibers themselves in this area have a slight curve at their top forming the shape of the required angle.
  • the fibers in this section are coupled to an elongated strip of glass that covers them at the top, so that the top of the glass has a flat surface that faces the laser beam, and the bottom of the glass has a wavy surface that complements exactly the upper curves of the fibers, in order to make the absorption of the beam from the laser light more efficient.
  • this glass piece is separate per each fiber, so that it's actually more like each fiber is covered with one glass tooth with a flat top and a concave bottom, and the flat tops of these teeth touch each other side by side.
  • the "teeth" are glued to each other in order to make the entire structure more stable.
  • the laser beam does not hit the glass from straight up but at a certain angle, so that the light does not bounce back from the fibers.
  • This variation is shown in more detail in Fig. 8a. These "teeth" can be made at a large range of heights, and in the extreme case can even touch the magnifying optical device through which the laser beam (81) passes, so as to conduct the beam directly from the laser even without any air gap on the way.
  • Another variation of the last variation is a top glass that has the same flat surface above facing the laser beam, but its bottom is shaped like small upside-down triangle-shaped teeth so that each triangle creates a smaller beam that hits one fiber at a small point.
  • the "teeth" are glued together to a covering glass plate, in order to make the structure more stable.
  • This variation is shown in more detail in Fig. 8b.
  • Another variation is that at the area of the amplifier the fibers themselves are shaped a little differently - for example instead of round wires they are taller and thinner and have a flat top.
  • the laser beam (81) from the powerful laser pump or pumps enters the splitter (82) after passing through an optical device, such as preferably a strip of magnifying glass, for making the powerful beam (81) elongated enough sideways in order to cover the entire width of the group of fibers (74) that are lying side by side.
  • this magnification makes the laser light spread to a larger area, while still maintaining its coherent properties.
  • some filters are also added in order to prevent possible reflections and therefore some cross-talk of signal echoes between the individual fibers (84).
  • the pipe is actually much larger at the area of the amplifier, in order to accommodate the laser pump (or pumps) and its interface.
  • the illustration shows fewer fibers at the flat area compared to the rest of the pipe, the actual number is of course the same.
  • the splitter is preferably made of glass, it might also be made of other materials and not necessarily glass. Other configurations than a flat surface are also possible, so that the fibers in the area of the amplifier can be arranged for example also side-by-side in a semi-circle or other shapes.
  • this solution is most natural in case of using multi-fiber flat jackets, for example by spreading them side by side at the amplification station or by using a separate pump for each jacket.
  • the laser light is directed (by its positioning and/or by additional prisms) to enter the fibers at acceptable angles that do not cause it to escape through the cladding.
  • FIG. 8a we show a 3-dimensional illustrative drawing of a preferable way in which the small glass "teeth" (811) are coupled to the fibers (812) and face the laser pump beam (813) in the configuration that was described in Fig. 8.
  • FIG. 8b we show a 3-dimensional illustrative drawing of another preferable way in which the small glass "teeth" (821) are coupled to the fibers (822) and face the laser pump beam (823) in the configuration that was described in Fig. 8.
  • Fig. 9 we show an illustration of a preferable way of using optical means in the amplifier for conveying the energy from one or more powerful laser pumps (93) to individual fibers (92) spread side by side on the internal surface of the cable's pipe (91).
  • the pipe (91) is preferably enlarged, and the fibers (92) are spread side by side on the internal surface by either coupling them to the internal surface of the pipe, or coupling them to the external surface of an internal transparent medium (94), such as for example the same refractive glass from which the exterior of each fiber is made (as compared to its core).
  • an internal transparent medium such as for example the same refractive glass from which the exterior of each fiber is made (as compared to its core).
  • the beam from the powerful laser (93) comes from the center of the pipe after passing through an optical device (such as for example a conical prism) that makes the beam spread all around the inner circle and illuminate the fibers (92) at the same time.
  • the fibers are covered with an inner transparent ring between them and the laser beam, similar to the way that the glass "teeth" work in solution number 8.
  • This ring can be made at a large range of sizes, and in the extreme case can even touch the magnifying optical device through which the laser beam (93) passes, so as to conduct the beam directly from the laser even without any air gap on the way.
  • this magnification makes the laser light spread to a larger area, while still maintaining its coherent properties.
  • some filters are also added in order to prevent possible reflections and therefore some cross-talk of signal echoes between the individual fibers (92).
  • more than one powerful laser pump is used, then preferably they are all illuminating approximately the same area, or they are positioned at short intervals with similar interfaces within the area of the amplifier so that their effect is incremental, or all the laser pumps are at the same intersection point with the fibers, but each laser pump is illuminating only a part of the 360 angle, so that they complement each other.
  • Eventough the splitter is preferably made of glass, it might also be made of other materials and not necessarily glass.
  • the laser light is directed (by its positioning and/or by additional prisms) to enter the fibers at acceptable angles that do not cause it to escape through the cladding.
  • FIG. 10 we show a schematic illustration of a preferable way of using optical means in the amplifier for conveying the energy from one or more laser pumps (103) to individual fibers (102), spread preferably more or less evenly in a transparent solid (104) in the middle of the pipe, preferably made of the same refractive glass from which the exterior of each fiber is made (as compared to its core), or for example in a transparent fluid (104) preferably with a specific weight close to that of glass and a refractive index close to that of glass, so that the fibers can freely float there. (Another possible variation is to add electrostatic charge to the fibers in this area so that they spread away from each other).
  • the beam from the powerful laser (103) preferably passes through an optical device (such as for example a conical prism) that makes the beam spread all around the inner space of the cable in a small section of the area of the amplifier and illuminate all the fibers at the same time.
  • an optical device such as for example a conical prism
  • the inner surface of the pipe in the area of the amplifier is itself a mirror, so that it helps reflect back more light from the laser pump towards the fibers.
  • some filters are also added in order to prevent possible reflections and therefore some cross-talk of signal echoes between the individual fibers (102).
  • the fibers at the area of the amplifier are shaped a little differently, so that instead of the round glass cladding they have flat planes, for example hexagonal, octagonal, or other numbers of planes, so that the laser beam hitting them from various angles can still enter them more easily.
  • the inner core of the fiber can either remain round or also be made with flat planes fitting the glass cladding, however that would be more difficult to accomplish).
  • mirrors are used on the inner side of the pipe in this area, then preferably they are a little tilted preferably in the length direction in order to increase the chance of the reflection of the laser pump beam hitting the fibers at angles other than 90 degrees.
  • Another variation is that on each of these planes there is also some additional tilted glass surface, so, for example, even light coming at 90 degrees to the fiber will still hit the plane at an angle different from 90 degrees.
  • these planes are also covered with a thin layer of semi-transparent one- directional glass, so that it allows only the laser light to go in but no light signals can be reflected back out of the fibers.
  • the laser light is directed (by its positioning and/or by additional prisms) to enter the fibers at acceptable angles that do not cause it to escape through the cladding.
  • FIGs. 11 a- l id we show (through cross-sections) a few examples of some possible preferable structures of a flat cable (110).
  • the "walls" (111) support the flat structure against being squashed for example by the strong pressures in submarine cables, and the fibers (112) reside in the cells, in a relatively flat layout.
  • Many sizes of the cells and many different quantities of fibers per cell can be used.
  • the fibers can be in a single layer, or more than one layer at the bottom of the cell. This way the fibers can easily move up and down in their cells in response to different stresses for example when the cable is curved around the ship's wheel compared to when it's flat at the bottom.
  • miniatures cells might be used so each cell contains only one fiber, however, such a structure might be difficult to construct and not efficient.
  • the jacket is preferably made of some strong, thin, flexible, low friction plastic or nylon or other polymer.
  • the jacket can either allow free movement of the fibers in their "mini-cells" in all directions, or only in 1 direction (preferably the direction of the thickness of the jacket), or almost no movement at all (in which case the jacket is preferably just a little thicker than the fibers themselves), and can contain either just 1 fiber per cell or more than 1 fiber per cell.
  • the jacket has modular connectors or at least some other convenient modular pre-connector interface.
  • the jacket can contain just one layer of fibers, or more than 1 layer.
  • a 15 micron thick and 1.5 centimeters wide flat jacket can contain 1,000 10-micron optical fibers. Eventhough this jacket is planned mainly for long-distance applications, it can also be useful for all other distances, including very short distances.
  • Fig. 12a-b we show a number of examples of some preferable configurations in which a number of flat multi-fiber, preferably flexible, jackets (122) can be stacked upon each other within a preferably somewhat flattened pipe (121). This makes sure that the pipe will only bend in the desired direction so that the movement of the fibers up and down within the flat jackets and/or the movement of the jackets themselves up and down will compensate for the stress causes by the bending of the pipe.
  • each fiber is 10 micron and we put for example a spacing of 5 micron between them, we can build for example a flexible flat plastic jacket (122) that has a width of 1.5 centimeters and a thickness of for example 0.1 millimeters (100 micron) and contains 1,000 fibers, or for example a similar flat plastic jacket that contains 2,000 fibers and has a width of 3 centimeters.
  • each individual fiber can preferably move freely within its 100 micron space up and down to compensate for stress caused by bends in the metal pipe.
  • the metal pipe in this example is either a partially flat pipe with an inner width of at a little more than 1.5 centimeters and we put the exemplary 20 flat jackets in a stack on top of each other, or the metal pipe is even flatter and has for example two cells with a strengthening wall between them, and we put for example 10 jackets on top of each other in each of the two cells.
  • the inner height of the cable is 0.7 cm and the thickness of each flat jacket is 0.1 mm, it is still 70 times larger than the flat jacket, and the jackets can freely move up and down to compensate for stress caused by bends in the metal pipe.
  • the free movement of the fibers within the flat jacket is enough for compensating for bends in the pipe, we don't need the additional free movement of the jackets up and down and so can stack more such jackets together - for example 70 times more jackets and therefore 70 times more fibers.
  • the jacket is preferably opaque to light and preferably black or at least with dark color (including between the cells), in order to further decrease the chance of cross-talk between close fibers.
  • each fiber can move only 0.1 mm up or down in our example in response to stress caused by bending of the pipe, and in this extreme for example a 100 flat jackets, with a thickness of for example 15 micron each, occupy together about 1.5 mm and therefore can still move freely up or down almost 85% of a centimeter in a pipe of 1 cm internal height. Therefore, another preferable variation of this is to use a multi-layer flat jacket that has for example a 100 layers (and is preferably a little thicker at the two most external layers for better protection) or simply, for easier construction, for example a 100 flat jackets of the type described above are stacked together and wrapped by some slightly thicker additional protective material.
  • the fibers are each covered by a very thin layer of opaque, preferably dark, coating or color, with preferably the same thermal expansion coefficient as glass, to avoid cross-talk between the fibers, or immersed in on opaque dark liquid or powder (such as fine carbon dust).
  • Another possible variation is using the multi-layer hybrid variation suggested above, so that for example we stack 100 ultra- thin flat jackets of 1-micron fiber together on top of each other and then add a somewhat thicker external envelope to make is stronger, and then altogether it still has a thickness similar to 1 flat jacket of 10-micron fibers.
  • a 100 of these exemplary 80,000 fibers flat jackets on top of each in the pipe we get something the thickness Of about 1.5 mm that can move freely up and down in the pipe to compensate for stress caused by bending, and contains 8 million 1-micron fibers.
  • the number of cells in the metal pipe itself can be 1 or 2 or more, so various combinations of flat jackets and a flat metal pipe can also be made.
  • One preferable method of manufacturing the flat multi-fiber jackets is, for example, putting a large number of fiber reels at a sufficiently large area, and pulling them next to each other side by side with methods similar to textile factories, and then running them through a machine which extrudes the jackets around them on the fly, or letting them pass through an appropriate liquid solution, etc.
  • the various reels and relay wheels are computer-controlled for exact coordination, and also there are tension sensors to avoid stressing fibers too much during the process.
  • a fiber gets torn or damaged in the process this is automatically sensed, and then either the fiber is marked as bad, or the process is temporarily halted and the fiber is preferably fixed by welding, and then the process continues.
  • the jackets are extruded around the fibers, they can either be extruded to fit exactly around the fibers, or they can be extruded with the right size of holes so that the fibers can have the amount of free space desired. If the fibers pass through some liquid solution for forming the jackets then it is more natural to have no free space between the fibers and the jacket, however even in this method some free space might be created for example by first covering the fibers with some volatile material which evaporates after the jacket has been formed around them, thus leaving the desired free space. Referring to Fig.
  • the space between each two adjacent fibers in the flat jacket is preferably larger (than in the examples given in Figs. 12a and b) and the jacket is thinner, for example 30 micron space between each two adjacent 10-micron fibers and a jacket thickness of 0.03 mm (30 micron).
  • This would make the flat jacket of 20,000 fibers with a width of about 800,000 micron 80 cm.
  • the diameter of the "rollada" will still be about 0.3 cm.
  • a, preferably flexible, multi-layer, preferably elongated square, structure (122) which is already shaped in multi-layer format, without the need to roll it, so that each fiber still has enough room to move freely in its own channel and said structure is preferably within a somewhat flattened pipe (121), in order to make sure that the pipe bends only in the desired direction.
  • the fibers (123) have more free room to move up and down than sideways. This saves space by giving the fibers free movement especially in the direction that is needed to compensate for stress caused by bands in the pipe and less free movement in the other direction, so that more fibers can be safely stacked together sideways.
  • a multi-fiber flat-jacket connector (132) that is shaped like a fan or delta, so that the distances between the fibers (131) increase near the connector in order to allow more convenient access to the fibers, for example when connecting them to the laser interface that sends the lambda signals into the fibers.
  • the distances between the fibers at the end of the connector (133) and the orientation (preferably, all pointing at exactly the same direction in parallel) of the fibers (133) are kept extremely accurate, by using very accurate filaments between the fibers at the connector (132), which are all of the same size, preferably to a micron- level accuracy or even higher.
  • the material of the connector and of these filaments and the material of the flat jacket itself have a very similar thermal expansion coefficient.
  • Fig. 13a the fibers remain with the same thickness in this "delta”.
  • Fig. 13b is very similar to Fig. 13a, except that the fibers are also getting gradually thicker at the delta as they approach the connector.
  • the fibers for example gradually each grow to a thickness of for example 10 times their normal thickness, then for example a flat jacket of 1000 fibers with a normal width of about 1.5 cm will have a connector with the size of approximately 15 cm.
  • a flat jacket of 1000 fibers with a normal width of about 1.5 cm will have a connector with the size of approximately 15 cm.
  • the fibers' edges at the end of the connector are preferably already cut very straight and well-polished.
  • Such connectors can help for example at the connection with the lasers that insert the input signals into the fibers, at the connection with the signals detectors, at the area of the amplifiers, in small-distance point-to-point connections, and/or in various junctions or optical splitters at the routers.
  • connection with the laser diodes such an expanded connector is convenient because the laser diodes are typically each larger than the fiber.
  • the variation described in Fig. 13b is especially important if we move for example to thinner fibers, such as for example 5 micron instead of 10 micron.
  • Fig, 13c we show a top view illustration of two connectors (132) in the process of being coupled to each other with he aid of a coupling interface (134).
  • the connection can either be mechanical, so that two connectors can be mechanically coupled to each other in a way that each fiber is touching and mechanically well coupled to the appropriate fiber as optimally as possible, or (since fused fibers work typically better than a mechanical interface) the connectors can be used as a jig to help a fusing machine automatically weld each two fibers together.
  • the coupling interface (134) can be for example a very exact array of short glass hollow tubes embedded in parallel in a rigid connector of the same material and size as the connectors (132), so that the connectors (132) are exactly coupled mechanically to the interface connector (134) and each hollow glass tube fits exactly over two facing fibers between the two connectors (132).
  • Another variation is that in one of the two connectors (132) the fibers get thicker as in Fig. 13b and become hollow at the end, and the fibers at the other connector fit exactly into each hole of the corresponding fiber when the two connectors are coupled to each other.
  • the thin wires on the other connectors are also getting somewhat fatter, so that the cores on both connectors are similar or identical in size and only the glass claddings on one side are larger then the other and form the walls of the holes.
  • This way the communication direction is independent of the connector type. Otherwise, this kind of connection would be limited to sending signals from the thin side to the fat side, otherwise data could be lost.
  • Another preferable variation is that for example when the two connectors (132) are coupled together, two or more opposite- facing very exact wavy-like clump are mechanically closed on the fibers from the top and from the bottom and hold all pairs of "stitched" fibers together.
  • a further variation is that preferably some part of these clamps can be slightly moved to the right and others slightly moved to the left, so that the fibers are held in position with the addition of some force from the right and from the left.
  • Various combinations of these and other variations are also possible.
  • the two connectors are mechanically coupled together from the sides, leaving free access from above and/or from below to the bear fibers between them, so that each two matching fibers are in very close contact, and then an automatic welding machine sensor can for example reach the connecting point of the two fibers from below or from above, encircle the matching fibers at the connection point (for example by closing a clump made of two or more half-rings), make automatic adjustments to make the connection optimal, and then weld the two glass fibers with the appropriate heat required.
  • This welding can be done also in the variations where in one or both of the connectors the fibers are getting fatter at the connector.
  • These connectors in either the mechanical connection or the welded connection) are also another solution to the problem of stitching at sea for especially long submarine cables and for easier interface with the amplifiers.
  • stitching is done near or inside one of the amplifiers, to compensate for any attenuation caused by the stitches.
  • the flat jackets (142) in each pipe are in an elongated square cell which has a height smaller than the width of the jackets.
  • the empty spaces created at the top and at the bottom are preferably used for electrical wires (144 a-d) for the amplifiers. Additional smaller electrical wires can be used in the side spaces. This can also be combined with other solutions, so that for example these wires can be in addition to inner insulated layers of the pipe itself that are used as electrical wires.
  • the pipes are preferably smaller, so that altogether the complex of pipes is not larger than a single pipe of the type used today.
  • more than one cell per pipe can be used sideways and/or bottom-up (For example, even simply dividing each of the two pipes into two cells, one on top of the other, can solve the jacket orientation problem), but one cell per pipe is more efficient.
  • the cells preferably have walls that are straight and parallel to each other, since otherwise one or more flat jackets can get stuck while at one of the extremes and not get down again when needed.
  • the cell walls are also made of strong metal.
  • the light (152) from laser source (151) is optically split for example by an optically diffractive prism (153), preferably with alternating opaque and transparent stripes, into discrete sub-frequencies (154a-e), and then preferably each sub-frequency is amplified and modulated on/off separately for example by using an electro-absorptive modulator or Mach-Zehnder Modulator or a lithium niobate modulator (155a-e).
  • This can convert each single less precise laser to a group of more precise lasers. In other words each laser can be used for creating a number of lambdas.
  • the new modulated lambdas (158a-e) then enter a multiplexor (156) and are inserted into the optic fiber (157).
  • a multiplexor 156
  • each split for example into 10 lambdas.
  • the amplification and the on/off modulation are conducted simultaneously at the same place, for example by using a filter and on/off-modulating the amplification pump itself.
  • the separate beams also pass through a correcting lens that compensates for any spearing caused by the first prism.
  • this is used in combination with various filters for improving the purity of each lambda.
  • Another possible variation is for example to optically duplicate the original laser and then use a separate filter or set of filters for each lambda.
  • all of these units are combined on a single chip, with preferably many lasers and many fibers per chip.

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Abstract

De nos jours, avec l'explosion de transfert d'informations, les fibres optiques deviennent toujours plus rapides. Pour la plupart, les derniers progrès concernant les quantités de données que ces fibres peuvent transmettre par unité de temps ont été réalisés en ajoutant de plus en plus de longueurs d'onde en même temps (appelées lambdas) à la même fibre, un procédé que l'on appelle DWDM (multiplexage en longueur d'onde dense). Actuellement, une seule fibre optique peut se voir attribuer 80 ou même 160 lambdas différentes en même temps et il est probable que ce nombre s'accroisse. A ce jour, les débits binaires les plus rapides pour chaque lambda se situent autour de 10 ou 40 gigabits par seconde, mais il sera difficile de faire beaucoup mieux, étant donné que les débits binaires élevés présentent une tolérance bien moindre au problèmes de dispersion. Néanmoins, la demande de communications en bande large, alimentée principalement par la croissance d'Internet, ne cesse d'augmenter à un taux bien plus rapide que les capacités des fibres optiques. Par exemple, ces dernières années cette demande se multipliait par cinq chaque année et il est probable qu'elle continue d'augmenter. Actuellement, les efforts se concentrent principalement sur l'accroissement du nombre de Lambdas par fibre, mais une fois qu'il aura été doublé quelques fois de plus, il deviendra difficile de l'accroître davantage. La présente invention vise à effectuer un grand bond dans ce domaine en atteignant un nombre beaucoup plus important de fibres par câble, par exemple 1000 ou 10.000 fois le nombre actuel, avec une diminution des coûts réduits de plusieurs ordres de grandeur. La présente invention permet de résoudre différents problèmes mécaniques, optiques et électroniques que pose la concentration d'un si grand nombre de fibres dans un seul câble. Une des principales caractéristiques de la présente invention consiste en l'utilisation de gaines plates flexibles multifibre qui peuvent se déplacer librement à l'intérieur du tuyau du câble, le tuyau étant de préférence divisé en au moins deux cellules, de sorte qu'il puisse s'infléchir uniquement dans la direction souhaitée et présenter un force structurelle maximale. Une autre caractéristique principale consiste en la possibilité qu'ont les connecteurs destinés à ces gaines de pouvoir également résoudre bon nombre d'autres problèmes. Une autre caractéristique importante concerne différents procédés permettant d'optimiser l'efficacité d'amplification de plusieurs fibres à la fois.
PCT/IL2001/001075 2000-11-21 2001-11-21 Systeme et procede permettant de transferer une quantite d'informations beaucoup plus importante dans des cables a fibres optiques en augmentant sensiblement le nombre de fibres par cable WO2002042801A2 (fr)

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CA002428128A CA2428128A1 (fr) 2000-11-21 2001-11-21 Systeme et procede permettant de transferer une quantite d'informations beaucoup plus importante dans des cables a fibres optiques en augmentant sensiblement le nombre de fibres par cable
GB0301155A GB2379519B (en) 2000-11-21 2001-11-21 System and method for transferring much more information in optic fiber cables by significantly increasing the number of fibers per cable
AU2002220998A AU2002220998A1 (en) 2000-11-21 2001-11-21 High capacity optical fiber cables
US10/307,422 US20030174977A1 (en) 2001-02-05 2002-11-27 System and method for transferring much more information in optic fiber cables by significantly increasing the number of fibers per cable
US11/162,105 US20070047885A1 (en) 2000-11-21 2005-08-29 System and method for transferring much more information in optic fiber cables by significantly increasing the number of fibers per cable
US12/039,867 US7899290B2 (en) 2000-11-21 2008-02-29 System and method for transferring much more information in optic fiber cables by significantly increasing the number of fibers per cable

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IL139810 2000-11-21
IL13981000A IL139810A0 (en) 2000-11-21 2000-11-21 System and method for transferring much more information in optic fiber cables by significantly increasing the number of concurrent communication channels
US26673101P 2001-02-05 2001-02-05
US60/266,731 2001-02-05

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US11/162,105 Continuation-In-Part US20070047885A1 (en) 2000-11-21 2005-08-29 System and method for transferring much more information in optic fiber cables by significantly increasing the number of fibers per cable

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GB2383850B (en) * 2001-11-27 2006-08-30 Yaron Mayer Optic fibre cable with large numbers of fibres
DE10251975A1 (de) * 2002-09-19 2004-04-01 Norddeutsche Seekabelwerke Gmbh & Co. Kg Lichtwellenleiterkabel und Anordnung zur Übertragung von Daten mit einem Lichtwellenleiterkabel
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GB2379519A (en) 2003-03-12
CA2428128A1 (fr) 2002-05-30
WO2002042801A2 (fr) 2002-05-30
GB2379519B (en) 2005-08-31
WO2002042801A3 (fr) 2002-10-24
AU2002220998A1 (en) 2002-06-03

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