Classifications

• • 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
  • H04B10/25—Arrangements specific to fibre transmission
  • H04B10/2589—Bidirectional transmission

Definitions

• the invention relates to a switched optical fiber network for aircraft seats.
• the purpose of the invention is in particular to secure such a network in the event of failure of one of its switching elements.
• screens are integrated into each seat, both for the broadcasting of entertainment programs (music, movies, video games, etc.), than for the transmission of safety messages (buckling of the belts , use of electronic devices, etc.).
• These screens are networked to a central or server computer.
• FIG. 1 thus shows a known network 1 in which screens 2.1-2. N of seats 3.1-3. N are connected to a server 4. These screens 2.1 -2.N are connected to the server 4 via 4.1-4.3 network switches or switches. These switches 4.1-4.3 transmit the information received on one of their ports to the screen for which it is intended.
• the cables 5, which provide the links between the switches 4.1-4.3 and the server 3 are copper cables in which circulate signals that are generally the standard of the Ethernet bus.
• This type of network has the disadvantage of being heavy since copper is a high density metal.
• One solution is to replace it with aluminum whose density is 3.3 times lower.
• aluminum being an uncommon use - at least for cables of small sections -, it poses difficulties in terms of connection to the connectors, as well as in terms of quality of contact and risk of corrosion.
• this type of network produces a relatively intense electromagnetic field, which requires taking a lot of precautions both to avoid disturbing nearby electronic equipment, to be parasitized by the equipment of the aircraft.
• optical couplers 10.1-10.3 replace the previous switches.
• These 10.1-10.3 optical couplers are light breakers that have no components that can fail, and require no power supply.
• the weight of the fiber, by itself, is negligible, and the light ray, not only does not generate parasites, but is insensitive to electromagnetic disturbing fields.
• Such a network is called PON network (for Passive Optical Network in English).
• PON network for Passive Optical Network in English.
• each 10.1-10.3 coupler introduces attenuation of the signal which limits the number of places connected to a single fiber.
• a passive optical network can hardly serve more than twelve seats. This requires either to multiply the number of optical fibers or to re-amplify the light signal every twelve couplers; in which case, we find the risk of failure of the Ethernet bus using copper cables.
• the invention proposes to overcome these disadvantages of the aforementioned optical network.
• the simple couplers are replaced by active optical switches of the MEMS type (for Micro Electro-Mechanical Systems in English) which comprise a mobile micro-mirror.
• the switch can thus orient the light signal flowing in the optical fiber in two directions. One is stable in the absence of control (rest position), the other is temporary and is obtained only when a voltage is applied to the switch. In the temporary position, the switch routes the light beam to the screen and re-amplifies it in the optical fiber, while in the rest position, the switch directly routes this light beam to the next seat.
• the switch is an active device. However, it says “positive security” since in case of failure of the control electronics, or loss of power, the switch naturally returns to the rest position. Thus, not only do downstream seats continue to receive safety and entertainment programs in the event of a malfunction, but due to local re-amplification, the number of seats that can be served is theoretically unlimited.
• the optical network according to the invention is therefore suitable for new high capacity aircraft.
• the invention therefore relates to a switched optical fiber network for aircraft seats, this network comprising screens interconnected via an optical fiber, a light signal flowing in this optical fiber to these screens,
• this network further comprising an upstream switching box and a downstream switching box connected in series on the optical fiber with respect to each other, the upstream switching box being positioned upstream of the downstream switching box,
• the upstream switching box comprises means for passing the light signal to the downstream box when said upstream box is not energized
• the upstream switching box comprising means for deflecting the light signal towards the screen to which it is connected, and means for amplifying the light signal and transmitting it to the downstream switching box when said upstream box is under voltage.
• the upstream switching box comprises an optical switch, this optical switch comprising a fixed mirror and two mirrors movable in rotation about an axis. These mirrors are positioned in such a way that they reflect the light signal towards the switch box downstream when the switch is not energized, the switch then being in a rest position. These mirrors are positioned in such a way that they reflect the light signal to the screen, and to the downstream switch when the optical switch is energized, the optical switch then being in an active position.
• each moving mirror of the optical switch has a first and a second control electrode.
• the first electrode is positioned on one end of the movable mirror and the second electrode is positioned on a fixed portion of the switch.
• the optical switch is in the home position when both electrodes are not energized while in the active position when both electrodes are energized.
• the upstream switching box further comprises a converter positioned between the screen and the optical switch of the upstream box. This converter transforms the light signal emitted on the optical fibers into an electrical signal transmitted to the screen and vice versa, as well as the amplification of the light signal emitted towards the downstream switching box.
• an Ethernet-type network switch is connected between the optical switch of a switch box and the screen to which it is connected, other screens being connected to this network switch.
• a server is connected to the screens via the optical fiber, this server transmitting information, such as setpoint information, to the screens of the network.
• the optical fiber is bidirectional.
• FIG. 1 (already described): a schematic representation of a network comprising copper cables according to the state of the art;
• FIG. 3 a schematic representation of a switched optical fiber network according to the invention
• Figures 4a, 4b schematic representations of the optical switches according to the invention in their operating positions
• FIG. 5 a schematic representation of a variant of the optical fiber network according to the invention.
• FIGS. 6a-6b schematic representations of a switching device connecting the optical switch to its power supply respectively in a closed and open state
• FIG. 7 a schematic representation of a network architecture comprising network monitoring modules ensuring the control of the optical switches.
• FIG. 3 shows a switched optical fiber network 1 for aircraft seats 3.1-3. N.
• This network 1 has screens 2.1-2. N connected to each other and to a server 4 via an optical fiber 9.
• These screens 2.1-2. N each comprise a computer (not shown) with a network card that allows them to exchange information on an Ethernet type network.
• These screens 2.1 -2.N are connected to the optical fiber 9 via switching boxes 13.1-13.N connected in series with respect to each other.
• Each switch box 13.1-13. N has an optical switch
• the server 4 is also provided with a converter 12 connected on the one hand to this server 4 and on the other hand to the optical fiber.
• Converters 12, and 15.1-15. N convert electrical signals, such as the Ethernet standard, into a light signal and vice versa. These converters are bidirectional so as to receive the signals of the optical fiber 9 to transmit them to the 2.1 -2.N screens or the server 4, or to receive data from these screens 2.1 -2.N or server 4 to transmit them on the optical fiber 9.
• This switch 14.1 which is in an active position, deflects the signal 19 to the converter 15.1 which transforms it into an electrical signal.
• This electrical signal is then transmitted to the screen 2.1 which displays the security information associated with this signal.
• the signal 20 is also transmitted to the converter 16.1 which transforms it into a light signal whose content is identical to the signal 19.
• This signal 21 has been amplified by the converter 16.1, so as to compensate for the attenuation provided by the optical fiber on section 9.1 and switch 14.1.
• This signal 21 is then sent to the optical switch 14.1 which deflects it towards the optical switch 14.2 positioned downstream with respect to the switch 14.1, via a section of optical fiber 9.2.
• This optical switch 14.2 which is in a rest position (because it is no longer powered due to a malfunction), does not deviate the light signal 21 towards the screen 2.2.
• the signal 21 is then transmitted directly to the switch 14.3 via the optical fiber section 9.3.
• This switch 14.3 then transmits this signal 21 to the screen 2.3 and re-transmits an optical signal 22 amplified with respect to the signal 21.
• the signal 22 is then transmitted to the switch 14. N via the fiber section 9.N.
• This switch 14.N also in the active position, transmits the signal 22 to the screen 2.N and re-amplifies, and so on.
• the information signal sent by the server 4 can thus be transmitted to all the screens 2.1, 2.3, 2.N associated with a optical switch in good working order, even if some switches of the network, such as the switch 14.2, do not work. not correctly.
• each optical switch 14.1-14. N comprises a fixed mirror, and a first 26 and a second mirror 27 respectively rotatable about an axis 26.1 and 27.1 perpendicular to the plane of the sheet.
• the fixed mirror is positioned between the movable mirrors 26, 27.
• the first movable mirror 26 In the rest position shown in FIG. 4a (which is that of the switch 14.2), the first movable mirror 26 has an angle a such that it reflects the light signal 21 coming from the fiber towards the fixed mirror 25.
• This fixed mirror reflects the signal from the moving mirror to the second movable mirror 27.
• This second mobile mirror 27 has an angle b such that it reflects the signal from the fixed mirror 25 to another switch.
• the first mirror 26 has an angle a 'such that it reflects the light signal coming from the fiber towards the screen, while the second mirror 27 mobile has an angle b 'as it reflects the signal 21 from the screen to another switch.
• each movable mirror 26, 27 comprises a first 31 and a second 32 control electrode, as shown in FIG. 4c.
• the switch 31 is positioned on one end of the movable mirror 26, 27 and the second electrode 32 is positioned on a fixed part 33 of the switch.
• the two electrodes 31, 32 are separated from each other by a mechanical force applied by a spring, for example positioned in the rotation shaft, so that the mirrors 26, 27 form respectively an angle a and b with the horizontal.
• the switch is then in the idle position (solid line position).
• the electrodes 31, 32 When the electrodes 31, 32 are energized, they attract each other, so that the mirrors 26, 27 rotate and move closer to the support 33. The mirrors 26, 27 then form the angles a 'and b 'with the horizontal. The switch is then in the active position (dotted position).
• the mirrors 26, 27 move from a rest position to an active position by means of a repulsive force.
• the rotation of the mirrors 26, 27 is controlled by means of motors.
• energizing the electrodes causes a twisting of the mirrors 26, 27 mounted on a flexible material.
• FIG. 5 shows a variant of the invention in which each seat 3.1 -3.N comprises several places and therefore several screens 2.1-2.N.
• the onboard network does not serve a single space but a row of two, three or four seats as shown.
• each switch 33.1 -33.N is connected on the one hand to the converters 15.1 and 16.1 of a housing and on the other hand to the screens 2.1-2. N of a row of seats.
• the number of optical fibers is multiplied so that it is possible to connect two sets of seats 37.1 and 37.2 (or more) to the server 4 via separate optical fibers 9 and 35.
• the seats of the set are multiplied so that it is possible to connect two sets of seats 37.1 and 37.2 (or more) to the server 4 via separate optical fibers 9 and 35.
• the seats of the set are multiplied so that it is possible to connect two sets of seats 37.1 and 37.2 (or more) to the server 4 via separate optical fibers 9 and 35.
• FIG. 37.2 (not shown) are connected to each other and to the server 4 in the same way as the seats 3.1 -3.N of the assembly 37.1 already described.
• Figures 6 show an optical switch 14.1 connected to its power supply 38 via a switch 39, such as a transistor operating in all-or-nothing mode or any other equivalent switching device.
• the optical switch 14.1 When the switch 39 is closed, as shown in Figure 6a, the optical switch 14.1 is powered so that it is active and ensures the transmission of data to the network switch 33.1 with which it is associated. While when the switch 39 is open as shown in Figure 6b, the optical switch 14.1 is not powered so that it is at rest and transmits the signals received from the network directly to the next optical switch 14.2, without sending them. to the network switch 33.1 with which it is associated in order to isolate the 2.1 screens which are connected to it.
• a monitoring module 40.1 controlling the opening and closing of the switch 39 is associated with each network switch 33.1-33. N, this monitoring module 40.1 whose function is to monitor the consistency of the information transiting the network.
• This monitoring module 40.1 may for example take the form of a microcontroller.
• monitoring module 40.1 controls the opening of the switch 39 so as to put the switch 14 in the rest position.
• control module 40.1 controls the closing of the switch 39 so as to put the switch 14 in the active position.
• the parameters monitored by the monitoring module 40.1 may for example be the number of acknowledgment signals transmitted by each of the screens 2.1-2. N (this parameter makes it possible to measure the congestion of the network), or the number of frames sent by each of the screens 2.1 -2.N which have replaced higher priority frames.
• the thresholds associated with these different parameters can be different and can be parameterized.

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• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Optical Communication System (AREA)
• Use Of Switch Circuits For Exchanges And Methods Of Control Of Multiplex Exchanges (AREA)
• Selective Calling Equipment (AREA)
• Mechanical Light Control Or Optical Switches (AREA)

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• 2007
  • 2007-01-05 FR FR0752542A patent/FR2911229B1/fr active Active
• 2008
  • 2008-01-07 WO PCT/FR2008/050018 patent/WO2008099098A2/fr active Application Filing
  • 2008-01-07 EP EP08761896A patent/EP2106638A2/fr not_active Ceased
  • 2008-01-07 BR BRPI0806306-0A patent/BRPI0806306A2/pt not_active IP Right Cessation
  • 2008-01-07 JP JP2009544439A patent/JP5331706B2/ja active Active
  • 2008-01-07 US US12/521,832 patent/US8380063B2/en active Active
  • 2008-01-07 CN CNA2008800016708A patent/CN101611576A/zh active Pending

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