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
  • G02B6/36—Mechanical coupling means
  • G02B6/38—Mechanical coupling means having fibre to fibre mating means
  • G02B6/3807—Dismountable connectors, i.e. comprising plugs
  • G02B6/381—Dismountable connectors, i.e. comprising plugs of the ferrule type, e.g. fibre ends embedded in ferrules, connecting a pair of fibres
  • G02B6/3813—Dismountable connectors, i.e. comprising plugs of the ferrule type, e.g. fibre ends embedded in ferrules, connecting a pair of fibres for transmission of high energy beam
• • 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
  • G02B6/4296—Coupling light guides with opto-electronic elements coupling with sources of high radiant energy, e.g. high power lasers, high temperature light sources
• • 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
  • G02B6/02—Optical fibres with cladding with or without a coating
  • G02B6/02052—Optical fibres with cladding with or without a coating comprising optical elements other than gratings, e.g. filters

Definitions

• the present invention relates to an optical fiber contact for transmitting moderate-magnitude optical power, specifically power in the range of 50-500 W, comprising an optical fiber having an inner core and a surrounding cladding for transmitting the radiation within the core, as well as additional surrounding layers or protecting jackets in order to mechanically stabilise the optical fiber.
• Optical fiber cables for transmitting optical power in the range of some mW up to several kW are frequently used in industrial applications.
• specific type of contacts have been developed to transmit the radiation between different units.
• SMA contact type
• the ferrule can be made of a metal, or a ceramic material in order to sustain more high optical power.
• Such a contact is small and has a low manufacturing cost, but has a limited use because of low cooling capacity so that the contact might be damaged under heavy heating. For that reason there are other types of fiber contacts for high optical power on the market which are based on the fact that a certain length of the fiber is detached.
• an optical fiber has an inner core made of glass and one or more surrounding layers having a refractive index which exceeds the refractive index of the core in order to "lock" the radiation into the core without any power loss.
• a surrounding layer or layers are called the cladding of the fiber.
• Outside the cladding there are also one or more protecting layers to stabilise the fiber mechanically.
• These layers are called buffers or jackets, and they are optimized for a high mechanical capacity but they do not have the necessary optical capacity to take care of high optical power.
• radiation entering into the cladding such radiation is propagating through the cladding up to the area in which the surrounding protecting layers are connected to the cladding. This is a critical region of the fiber, and therefore a damage might be expected here.
• an optical fiber contact for high optical power.
• the end surface of the fiber is in optical contact with a body of a transparent material, for instance a rod or any other type of a solid body made of quartz, which body in connection with the optical fiber end has a surface area exceeding the contact surface area of the fiber end and has a conical design.
• a more efficient flowing geometry is provided around the fiber end.
• such a surface provides an increased area for incident power loss radiation as well as deflection of such incident radiation towards the optical axis of the fiber contact.
• the cooling methods which have been described now can be used also for very high optical power.
• such optical fiber contacts are complicated, expensive and voluminous.
• There is a need for an optical fiber contact to be used for moderate-magnitude power radiation, typically 50-500 W, and which are not too complicated and voluminous.
• the forward part of the optical fiber contact is transparent so that power loss radiation is leaving the fiber contact in the form of optical radiation without any heating of the contact.
• the forward part of the optical fiber contact is surrounded by a transparent tubular member, preferably made of a material similar to the cladding material.
• the tubular member is extending a certain length along the outer cylindrical surface of the cladding, surrounding and connected to the cladding along this length distance.
• tubular member and the fiber are fused together at the front end to provide a single mechanical structure.
• Figure 1 illustrates what happens in a typical optical fiber contact when over-heated
• Figure 2 schematically illustrates an optical fiber contact according to the invention in which the forward part of the optical fiber contact is surrounded by a transparent tubular member
• Figure 3 illustrates an alternative embodiment with a non-transparent, but light-scattering member arranged in the rear region of the contact
• Figure 4 illustrates a first application example of the fiber contact
• Figure 5 illustrates a second application example of the fiber contact
• Figure 6 illustrates a device for minimizing back-reflections.
• FIG 1 it is illustrated the general design of a conventional optical fiber having areas which might be over-heated and damaged when the fiber is exposed to incident power loss radiation.
• the optical fiber comprises an inner core 1 , for instance made of quartz glass, for transmitting radiation, and a surrounding cladding 2, for example made of glass or some polymer, and having a refractive index exceeding the refractive index of the core to optically "lock" the radiation into the core without any power loss.
• cladding there are one or more layers 3 of protecting jackets or buffers to mechanically stabilise the fiber. These layers are optimized for mechanical capacity and does not necessarily have the required optical capacity to take care of high optical power.
• the fiber As the fiber is built into a contact member the fiber also has to be fixed positioned by means of any mechanical component. These outer mechanical components have not been illustrated in figure 1.
• FIG 2 it is illustrated an optical fiber contact which according to the invention is provided with a transparent forward part 7. This means that there is no heating by power loss radiation, as the power loss radiation is leaving the contact as optical radiation.
• the fiber with its core 1 and cladding 2 is inserted into a transparent tubular member 8 preferably made of a material similar to the cladding, i e made of glass or some polymer, having the same refractive index, or slightly higher than the cladding.
• the transparent tubular member 8 is surrounding the cladding along a certain distance 10, so that the inner cylindrical surface of the tubular member is adapted to the outer cylindrical surface of the cladding.
• the tubular member and the fiber are preferably fused together to form a mechanical structure 9.
• a mode stripper schematically illustrated by the dotted line 2' in figure 2, either by means of a roughening of the cladding surface to a matt-finish or by means of a further layer having a refractive index corresponding to the refractive index of the cladding, or slightlyt higher. If radiation for some reason goes into the cladding, such radiation is gradually leaving the cladding along a certain distance 10. The distance 10 should be long enough so that the remaining radiation in the cladding does not harm the surrounding layer or details.
• At least one of the cylindrical surfaces of the outer tubular member could be roughened like the cladding or matt-finished, so that the radiation is reflected away from this sleeve prior to the termination of the contact.
• the distance 10 should be selected long enough so that the radiation power is reduced to such a level that it does not harm components and glue joints at the rear part of the contact. This means that glue joints 11 and non-transparent mechanical components such as locking nuts 12 and rings 13 could be used in these rear regions, as the radiation power has been reduced to such an extent that it does not harm.
• the length of the transparent tube is typically 30-100 mm, while its outer diameter is typically 1-5 mm.
• the end surface of the fiber is centered against the outer diameter of the transparent tubular member 8 in the forward part 7 of the fiber contact. If necessary grinding of the surface might be carried out for the centering.
• FIG 3 it is illustrated another example of the fiber contact.
• the optical fiber with its core 1 and cladding 2 is inserted into a transparent tubular member 8, preferably made of a material similar to the cladding material, i e glass or some polymer.
• a transparent tubular member 8 preferably made of a material similar to the cladding material, i e glass or some polymer.
• the sleeve and the fiber are fused together to form a mechanical structure 9.
• the non-transparent, non-absorbing but light-scattering sleeve member 14 could be made of for instance aluminium oxide ceramics
• FIGS 4 and 5 it is illustrated some proposed applications of the fiber contact.
• the forward part of the fiber contact is hold by means of a supporting element 15 having a conical aperture 16. If necessary this supporting element 15 can be made of a non-absorbing material.
• the mechanical design of the forward and rear parts of the fiber contact provides for a cavity 17 formed between the outer transparent tubular member 8 of the fiber contact, a cylindrical housing 18, the front supporting element 15 and rear supporting rings 12, 13. By means of this cavity 17 the power loss is distributed over an increased surface, which means that the risk for over-heating and damages is minimized.
• FIG 5 it is illustrated another application in which the fiber contact is arranged in a substantially cylindrical guiding member 19 in a surrounding body 20 made of a heat- conducting material. If necessary this body might be provided with channels 21 for water cooling.
• the front end 22 of the fiber contact might be inclined by grinding and polished, see figure 6.
• the radiation is deviated by means of the inclined and polished end surface of the fiber contact.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Optical Couplings Of Light Guides (AREA)
• Mechanical Coupling Of Light Guides (AREA)
• Light Guides In General And Applications Therefor (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=40511676

Family Applications (1)

Country Status (6)

Families Citing this family (7)

Citations (2)

Family Cites Families (9)

• 2007
  • 2007-09-25 SE SE0702125A patent/SE531871C2/sv unknown
• 2008
  • 2008-09-19 JP JP2010525779A patent/JP5634866B2/ja active Active
  • 2008-09-19 ES ES08834001.3T patent/ES2519470T3/es active Active
  • 2008-09-19 WO PCT/SE2008/000526 patent/WO2009041874A1/en not_active Ceased
  • 2008-09-19 US US12/679,589 patent/US8412009B2/en active Active
  • 2008-09-19 EP EP08834001.3A patent/EP2191311B1/en active Active

Patent Citations (2)

Non-Patent Citations (1)

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