Back to results
US 2001/0043389 A1Published application
Optical fiber amplifier control
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorsDag Bonnedal, Johan Sandell, Gunnar Forsberg
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorsDag Bonnedal, Johan Sandell, Gunnar Forsberg
Estimating the term…
An optical fiber amplifier has a length of active optical fiber, into which pump light from a pump laser is injected. The pump laser is locally controlled by a laser monitor diode, the pump laser and the laser monitor forming a pump laser module. The overall amplification of the amplifier is controlled by two control loops, a feed forward loop and a feed back loop, these two control loops also controlling the pump laser. The feed forward loop gives a fast response and receives as an input signal the output signal of an input monitoring diode. The feed back loop gives a slower response and sets the overall gain of the amplifier. The feed back loop use as an input signal the signal from an output monitoring diode. In the feed forward loop the input power level is biased and controlled by a set value from sources to provide a signal corresponding to or substantially agreeing with the pump power which maintains the desired gain, the sources providing offsets of characteristic curves indicating the overall behavior of the optical amplifier. The pump power level obtained by the conversion is then in a converter converted to correspond to or agree with or to have a behavior similar to that of the pump monitor signal locally controlling the pump laser. This gives a very fast and accurate control in spite of the non-linear behavior of the optical fiber amplifier.
An optical amplifying device comprising an optical fiber amplifier, a pump laser, a pump laser controlling unit controlling the pump laser, the optical amplifying device further comprising a feed forward loop and a feed back loop, the feed forward loop and the feed back loop being connected to provide an amplifier control signal to the pump laser controlling unit for stabilizing the output of the optical amplifying device and the feed back loop setting a gain of the optical fiber amplifier, characterized in that the feed forward loop is arranged to compensate for offsets in gain characteristic curves of the optical fiber amplifier.
An optical amplifying device comprising an optical fiber amplifier, a pump laser module including a pump laser and a pump laser monitor, the optical amplifying device further comprising a pump laser controlling. unit receiving a monitor signal from the pump laser monitor and controlling the pump laser in accordance with the monitor signal, the optical amplifying device further comprising a control loop, the loop being connected to provide an amplifier control signal to the pump laser controlling unit for stabilizing the output of the optical amplifying device, characterized in that the pump laser controlling unit comprises a signal converter arranged to receive the amplifier control signal, the signal converter converting the amplifier control signal received from the control loop, so that an output signal of the signal converter has a characteristic curve as a function of a signal incoming to the signal converter substantially agreeing with a characteristic curve of the monitor signal as a function of power of light output from the pump laser module.
A fiber optical network for transmitting optical signals, in particular WDM signals, comprising fiber optical links connected to at least one optical amplifying device, the optical amplifying device comprising an optical fiber amplifier, a pump laser, a pump laser controlling unit controlling the pump laser, the optical amplifying device further comprising a feed forward loop and a feed back loop, the feed forward loop and the feed back loop being connected to provide an amplifier control signal to the pump laser controlling unit for stabilizing the output of the optical amplifying device and the feed back loop setting a gain of the optical fiber amplifier, characterized in that the feed forward loop is arranged to compensate for offsets in gain characteristic curves of the optical fiber amplifier.
A fiber optical network for transmitting optical signals, in particular WDM signals, comprising fiber optical links connected to at least one optical amplifying device, the optical amplifying device comprising an optical fiber amplifier, a pump laser module including a pump laser and a pump laser monitor, the optical amplifying device further comprising a pump laser controlling unit receiving a monitor signal from the pump laser monitor and controlling the pump laser in accordance with the monitor signal, the optical amplifying device further comprising a control loop, the loop being connected to provide an amplifier control signal to the pump laser controlling unit for stabilizing the output of the optical amplifying device, characterized in that the pump laser controlling unit comprises a signal converter arranged to receive the amplifier control signal, the signal converter converting the amplifier control signal received from the control loop, so that an output signal of the signal converter has a characteristic curve as a function of a signal incoming to the signal converter substantially agreeing with a characteristic curve of the monitor signal as a function of power of light output from the pump laser module.
A method of amplifying optical signals, in particular WDM signals, the method comprising the steps of
A method of amplifying optical signals, in particular WDM signals, the method comprising the steps of
Dependencies are inferred from the claim text.