Polarization scrambler unit and multi-repeater transmission system incorporating the same

Abstract

The present invention minimizes trouble and loss caused by a failure polarization scrambler. A polarization scrambler unit 201 of the invention is provided with: two polarization scramblers 2 - 1 and 2 - 1 ; a switching unit for coupling either one of the polarization scramblers 2 - 1 and 2 - 1 to a transmission line fiber 4 ; a detection unit for detecting an output signal from the polarization scrambler 2 - 1 (or the polarization scrambler 2 - 2 ) coupled to the transmission line fiber 4 ; and a controlling unit for switching, via the switching unit, between the polarization scramblers 2 - 1 and 2 - 2 whenever a false output signal is detected by the detection unit. Thus, the polarization scrambler unit 201 has a redundant structure.

1 . A polarization scrambler unit comprising: 
 a plurality of polarization scramblers;    a switching unit for coupling one of the polarization scramblers to a transmission line fiber;    a detection unit for detecting an output signal from the polarization scrambler coupled to the transmission line fiber; and    a controlling unit for switching the polarization scrambler to another polarization scrambler using the switching unit when the output signal detected by the detection unit comprises a false output signal.    
   
   
       2 . A polarization scrambler unit according to  claim 1 , wherein the switching unit comprises: 
 an optical switch inserted between the polarization scrambler and the transmission line fiber; and    a switch driving circuit for opening and closing the optical switch.    
   
   
       3 . A polarization scrambler unit according to  claim 1 , wherein the switching unit comprises: 
 an optical amplifier inserted between the polarization scrambler and the transmission line fiber; and    an amplifier controlling circuit for controlling the optical amplifier.    
   
   
       4 - 9 . (canceled)  
   
   
       10 . A polarization scrambler unit according to  claim 1 , wherein the plurality of polarization scramblers includes two polarization scramblers.  
   
   
       11 . A polarization scrambler unit according to  claim 2 , wherein the plurality of polarization scramblers includes two polarization scramblers.  
   
   
       12 . A polarization scrambler unit according to  claim 3 , wherein the plurality of polarization scramblers includes two polarization scramblers.  
   
   
       13 . A multi-repeater transmission system in which a transmitter and a receiver are connected via a transmission line fiber and a plurality of optical amplification repeaters are inserted in the transmission line fiber, 
 wherein a plurality of polarization scrambler units are inserted in the transmission line fiber, and    wherein each of the polarization scrambler units comprises:    a plurality of polarization scramblers;    a switching unit for coupling one of the polarization scramblers to a transmission line fiber;    a detection unit for detecting an output signal from the polarization scrambler coupled to the transmission line fiber; and    a controlling unit for switching the polarization scrambler to another polarization scrambler using the switching unit when the output signal detected by the detection unit comprises a false output signal.    
   
   
       14 . A multi-repeater transmission system according to  claim 13 , wherein the switching unit comprises: 
 an optical switch inserted between the polarization scrambler and the transmission line fiber; and    a switch driving circuit for opening and closing the optical switch.    
   
   
       15 . A multi-repeater transmission system according to  claim 13 , wherein the switching unit comprises: 
 an optical amplifier inserted between the polarization scrambler and the transmission line fiber; and    an amplifier controlling circuit for controlling the optical amplifier.    
   
   
       16 . A multi-repeater transmission system according to  claim 13 , wherein the polarization scrambler units are inserted for every constant number of the optical amplification repeaters.  
   
   
       17 . A multi-repeater transmission system according to  claim 14 , wherein the polarization scrambler units are inserted for every constant number of the optical amplification repeaters.  
   
   
       18 . A multi-repeater transmission system according to  claim 15 , wherein the polarization scrambler units are inserted for every constant number of the optical amplification repeaters.  
   
   
       19 . A polarization scrambler unit comprising: 
 a plurality of polarization scramblers;    means for detecting an output signal from the polarization scrambler; and    means for switching the polarization scrambler to another polarization scrambler when the output signal detected by the means for detecting comprises a false output signal.    
   
   
       20 . A multi-repeater transmission system in which a transmitter and a receiver are connected via a transmission line fiber and a plurality of optical amplification repeaters are inserted in the transmission line fiber, 
 wherein the plurality of polarization scrambler units are inserted in the transmission line fiber, and    wherein each of the polarization scrambler units comprises: 
 a plurality of polarization scramblers;  
 means for detecting an output signal from one of the polarization scramblers; and  
 means for switching the one of the polarization scramblers to another of the polarization scramblers when the output signal detected by the means for detecting comprises a false output signal.  
   
   
   
       21 . The polarization scrambler unit according to  claim 1 , wherein the controlling unit automatically switches the polarization scrambler to another polarization scrambler using the switching unit when the output signal detected by the detection unit comprises a false output signal.  
   
   
       22 . The polarization scrambler unit according to  claim 1 , wherein the switching unit automatically switches the polarization scrambler to another polarization scrambler when the output signal detected by the detection unit comprises a false output signal.  
   
   
       23 . The polarization scrambler unit according to  claim 1 , wherein the detection unit automatically detects an output signal from the polarization scrambler coupled to the transmission line fiber.  
   
   
       24 . The polarization scrambler unit according to  claim 1 , wherein the switching unit couples only one of the polarization scramblers to the transmission line fiber.  
   
   
       25 . The polarization scrambler unit according to  claim 1 , wherein the switching unit couples an output of the transmission line fiber to one of the polarization scramblers.  
   
   
       26 . The polarization scrambler unit according to  claim 1 , wherein the switching unit comprises an optical switch inserted between the polarization scrambler and the transmission line fiber and disposed on an input side of the polarization scrambler.  
   
   
       27 . The polarization scrambler unit according to  claim 1 , wherein the switching unit comprises a switch driving circuit for opening and closing the optical switch.  
   
   
       28 . The polarization scrambler unit according to  claim 1 , wherein the switching unit comprises an amplifier controlling circuit for controlling the optical amplifier.