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
  • H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
  • H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
  • H04B10/077—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using a supervisory or additional signal
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B2210/00—Indexing scheme relating to optical transmission systems
  • H04B2210/08—Shut-down or eye-safety

Definitions

• the present invention relates to an arrangement for monitoring an optical fiber transmission link with the features of the preamble of claim 1.
• the pulse length of the test pulses and their intervals are dimensioned such that the power transmitted is low when integrated over time, and so there is no danger to the human eye when repairing the transmission link. Regulations in this regard are set out in CCITT recommendation G.958.
• the light intensity in the L L transmission path can be increased considerably.
• the pulse length of the test pulses cannot be chosen to be arbitrarily short because of the transient response when the laser transmitter is switched on, so that the monitoring method from DE 39 42 817 AI can no longer be used here.
• the invention has for its object to provide an arrangement of the type mentioned, even at very high Transmission power can be used without posing a health risk to the human eye when repairing the L L transmission path. This object is achieved by the features of claim 1. Advantageous embodiments of the invention emerge from the subclaims.
• the timing of the test pulses (pulse length, time interval) can be retained.
• the drawing shows a first and second transmitter S1, S2, a first and second receiver E1, E2 and an optical fiber (LWL) transmission link with two optical fibers LWL1 and LWL2.
• Optical fiber LWL1 connects the transmitter S1 to the receiver E2 and optical fiber LWL2 connects the transmitter S2 to the receiver El for the transmission of optical signals.
• the optical fibers LWL1 and LWL2 are operated by the transmitters S1 and S2 with high optical powers, such as are achieved, for example, by laser diodes with downstream optical fiber amplifiers.
• the signal transmission from the transmitter S1 to the receiver E2 fails.
• the arrangement for monitoring the optical fiber transmission link then switches off the transmitter S2, since no more optical signals are registered in the receiver E2. Since now no more optical signals are received in receiver El the transmitter S1 is also switched off by the arrangement.
• the fiber optic transmission link can now be repaired without endangering the human eye.
• the transmitters S1 and S2 are caused by the arrangement to send optical test pulses, e.g. by timer. These test pulses are sent approximately once per minute from the start of the fault, the pulse length is approximately two seconds.
• Your level will e.g. reduced by reducing the modulation current of a laser diode to such an extent that the powers that occur are no longer dangerous when integrated over time over pulse and pause times. Although this level is generally no longer sufficient for data transmission, it is only necessary to prove the test pulses.
• a sensitive detector with low response speed and bandwidth must be used in addition to the broadband receiver, since the test pulses can lie at the detection limit due to the attenuation in the optical waveguide, especially in long-distance transmission.
• the LWL transmission link automatically starts up again and sends data signals. This is brought about by the interconnection of the receivers E1 and E2 and the transmitters S1 and S2: If a test pulse arrives in a receiver (E1, E2), this causes the latter associated transmitter (Sl, S2), also send a test pulse. Now that the fault has been remedied, the test pulses arrive at both receivers El, E2 and both transmitters go into operation. The exact functioning of the automatic commissioning is described in DE 39 42 817 AI.
• Each intermediate regenerator is capable of sending and detecting test pulses.
• the arrangement switches off the transmitter in the opposite direction and causes it to send test pulses. Once the fault has been remedied, the transmitter of the section of the route concerned is put back into operation.
• a transmitter of this fiber optic transmission link can e.g. a laser diode with an optical fiber amplifier as a post-amplifier or a laser with high optical output power.

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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)

Applications Claiming Priority (3)

Publications (1)

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Family Cites Families (5)

• 1993
  • 1993-05-28 DE DE4317863A patent/DE4317863C2/de not_active Expired - Lifetime
• 1994
  • 1994-05-20 WO PCT/DE1994/000583 patent/WO1994028647A1/de not_active Application Discontinuation
  • 1994-05-20 CN CN94192260A patent/CN1124550A/zh active Pending
  • 1994-05-20 EP EP94915046A patent/EP0700606A1/de not_active Withdrawn

Non-Patent Citations (1)

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