US9270369B2ActiveUtilityA1

Correction table for interferometric optical signal-to-noise ratio monitor

Assignee: FUJITSU LTDPriority: Jan 13, 2014Filed: Jan 13, 2014Granted: Feb 23, 2016
Est. expiryJan 13, 2034(~7.5 yrs left)· nominal 20-yr term from priority
H04B 17/0085H04B 10/07953H04B 17/0062
50
PatentIndex Score
0
Cited by
23
References
26
Claims

Abstract

The present disclosure includes a computer-implemented method of correcting a measured optical signal-to-noise ratio (OSNR) comprising receiving an optical signal and measuring OSNR of the optical signal using an interferometric OSNR monitor device. The method also includes applying a correction table to the measured OSNR to generate a corrected OSNR using a controller, the correction table comprising a correction function to counteract an artifact in the measured OSNR. The method also includes storing the corrected OSNR in a non-transitory computer-readable medium. The present disclosure also includes associated devices applying the correction table and methods of generating the correction table.

Claims

exact text as granted — not AI-modified
What is claimed is:  
     
       1. A computing processor-implemented method for generating a correction table for correcting measured optical signal-to-noise ratio (OSNR), comprising:
 receiving an optical signal; 
 
       detecting, by a controller, an artifact associated with a measured OSNR of the optical signal; 
       calculating, by the controller, a correction function to counteract the artifact, the correction function varying over the measured OSNR; and
 storing the correction function in the correction table in a non-transitory computer readable medium; 
 wherein OSNR can be calculated and measured based on a set of parameters (s, a) related to the power distribution and calibration factors that can have different values for different optical signal modulation schemes. 
 
     
     
       2. The method of  claim 1 , further comprising:
 measuring a first OSNR with a first known value; and 
 measuring a second OSNR with a second known value; 
 wherein calculating a correction function of the artifact comprises:
 determining a first difference caused by the artifact between the first OSNR and the first known value; and 
 determining a second difference caused by the artifact between the second OSNR and the second known value. 
 
 
     
     
       3. The method of  claim 1 , wherein the artifact comprises one of a pass-band narrowing effect, an optical filter's frequency offset, and a transmitter's frequency offset. 
     
     
       4. The method of  claim 3 , wherein a different correction function of the correction table is generated if the artifact comprises a pass-band narrowing effect, an optical filter's frequency offset, or a transmitter's frequency offset. 
     
     
       5. The method of  claim 1 , wherein a different correction function is generated for different bandwidths, different powers of the optical signal, and different numbers of spans of a network traversed by the optical signal. 
     
     
       6. The method of  claim 1 , wherein the OSNR is measured using the equation: 
       
         
           
             
               
                 O 
                 ⁢ 
                 
                     
                 
                 ⁢ 
                 S 
                 ⁢ 
                 
                     
                 
                 ⁢ 
                 
                   NR 
                   ⁡ 
                   
                     [ 
                     dB 
                     ] 
                   
                 
               
               = 
               
                 10 
                 × 
                 
                   
                     log 
                     [ 
                     
                       
                         
                           ( 
                           
                             
                               
                                 
                                   ( 
                                   
                                     a 
                                     + 
                                     1 
                                   
                                   ) 
                                 
                                 · 
                                 
                                   ( 
                                   
                                     s 
                                     - 
                                     a 
                                   
                                   ) 
                                 
                               
                               
                                 
                                   ( 
                                   
                                     
                                       
                                         P 
                                         ⁢ 
                                         
                                             
                                         
                                         ⁢ 
                                         2 
                                       
                                       
                                         P 
                                         ⁢ 
                                         
                                             
                                         
                                         ⁢ 
                                         1 
                                       
                                     
                                     - 
                                     a 
                                   
                                   ) 
                                 
                                 · 
                                 
                                   ( 
                                   
                                     s 
                                     + 
                                     1 
                                   
                                   ) 
                                 
                               
                             
                             - 
                             
                               
                                 a 
                                 + 
                                 1 
                               
                               
                                 s 
                                 + 
                                 1 
                               
                             
                           
                           ) 
                         
                         
                           - 
                           1 
                         
                       
                       · 
                       
                         B 
                         R 
                       
                     
                     ] 
                   
                   ⁢ 
                   
                       
                   
                   . 
                 
               
             
           
         
       
     
     
       7. The method of  claim 1 , wherein the correction table includes corrections for OSNR from five dB to thirty-five dB. 
     
     
       8. The method of  claim 1 , wherein the correction table corrects the measured OSNR to within 0.5 dB of an actual OSNR. 
     
     
       9. A computing processor-implemented method of correcting a measured optical signal-to-noise ratio (OSNR), comprising: 
       receiving an optical signal;
 measuring OSNR of the optical signal using an interferometric OSNR monitor device; applying a correction table to the measured OSNR to generate a corrected OSNR using a controller, the correction table comprising a correction function to counteract an artifact in the measured OSNR; and 
 storing the corrected OSNR in a non-transitory computer-readable medium; 
 wherein OSNR can be calculated and measured based on a set of parameters (s, α) related to the power distribution and calibration factors that can have different values for different optical signal modulation schemes. 
 
     
     
       10. The method of  claim 9 , wherein the optical signal comprises a plurality of data-carrying wavelengths, further comprising:
 separating out a first data-carrying wavelength from the optical signal; 
 wherein the measured OSNR is measured for the first data-carrying wavelength and associated in-band noise. 
 
     
     
       11. The method of  claim 10 , wherein the optical signal comprises a plurality of data-carrying polarities, further comprising:
 separating out a first polarity of the first data-carrying wavelength; 
 wherein the measured OSNR is measured for the first polarity of the first data-carrying wavelength and associated in-band noise. 
 
     
     
       12. The method of  claim 9 , wherein the artifact comprises one of a pass-band narrowing effect, an optical filter's frequency offset, and a transmitter's frequency offset. 
     
     
       13. The method of  claim 12 , wherein a different correction function is applied if the artifact is a pass-band narrowing effect, an optical filter's frequency offset, or a transmitter's frequency offset. 
     
     
       14. The method of  claim 9 , wherein a different correction function is applied for different bandwidths, different powers of the optical signal, and different numbers of spans of a network traversed by the optical signal. 
     
     
       15. The method of  claim 9 , wherein the OSNR is measured using the equation: 
       
         
           
             
               
                 O 
                 ⁢ 
                 
                     
                 
                 ⁢ 
                 S 
                 ⁢ 
                 
                     
                 
                 ⁢ 
                 
                   NR 
                   ⁡ 
                   
                     [ 
                     dB 
                     ] 
                   
                 
               
               = 
               
                 10 
                 × 
                 
                   
                     log 
                     [ 
                     
                       
                         
                           ( 
                           
                             
                               
                                 
                                   ( 
                                   
                                     a 
                                     + 
                                     1 
                                   
                                   ) 
                                 
                                 · 
                                 
                                   ( 
                                   
                                     s 
                                     - 
                                     a 
                                   
                                   ) 
                                 
                               
                               
                                 
                                   ( 
                                   
                                     
                                       
                                         P 
                                         ⁢ 
                                         
                                             
                                         
                                         ⁢ 
                                         2 
                                       
                                       
                                         P 
                                         ⁢ 
                                         
                                             
                                         
                                         ⁢ 
                                         1 
                                       
                                     
                                     - 
                                     a 
                                   
                                   ) 
                                 
                                 · 
                                 
                                   ( 
                                   
                                     s 
                                     + 
                                     1 
                                   
                                   ) 
                                 
                               
                             
                             - 
                             
                               
                                 a 
                                 + 
                                 1 
                               
                               
                                 s 
                                 + 
                                 1 
                               
                             
                           
                           ) 
                         
                         
                           - 
                           1 
                         
                       
                       · 
                       
                         B 
                         R 
                       
                     
                     ] 
                   
                   ⁢ 
                   
                       
                   
                   . 
                 
               
             
           
         
       
     
     
       16. The method of  claim 9 , wherein the correction table includes corrections for OSNR from five dB to thirty-five dB. 
     
     
       17. The method of  claim 9 , wherein the correction table corrects the measured OSNR to within 0.5 dB of an actual OSNR. 
     
     
       18. A device for correcting a measured optical signal-to-noise ratio (OSNR) of an optical signal, the device comprising: a monitor device configured to generate values from which OSNR of the optical signal may be measured; a controller configured to measure the OSNR of the optical signal using the values generated by the monitor device and apply a correction table to the measure OSNR to generate a corrected OSNR, the correction table comprising a correction function to counteract an artifact in the measured OSNR; and non-transitory computer readable medium to receive the corrected OSNR from the controller and store the corrected OSNR; wherein OSNR can be calculated and measured based on a set of parameters (s, a) related to the power distribution and calibration factors that can have different values for different optical signal modulation schemes. 
     
     
       19. The device of  claim 18 , wherein the monitor device is further configured to separate out a first data-carrying wavelength from a plurality of data-carrying wavelengths in the optical signal, and the measured OSNR is measured for the first data-carrying wavelength and associated in-band noise. 
     
     
       20. The device of  claim 19 , wherein the monitor device is further configured to separate out a first polarity from a plurality of polarities in the optical signal, and the measured OSNR is measured for the first polarity of the first data-carrying wavelength and associated in-band noise. 
     
     
       21. The device of  claim 18 , wherein the artifact comprises one of a pass-band narrowing effect, an optical filter's frequency offset, and a transmitter's frequency offset. 
     
     
       22. The device of  claim 21 , wherein a different correction function is applied if the artifact is a pass-band narrowing effect, an optical filter's frequency offset, or a transmitter's frequency offset. 
     
     
       23. The device of  claim 18 , wherein a different correction function is applied for different bandwidths, different powers of the optical signal, and different numbers of spans of a network traversed by the optical signal. 
     
     
       24. The device of  claim 18 , wherein the OSNR is measured using the equation: 
       
         
           
             
               
                 O 
                 ⁢ 
                 
                     
                 
                 ⁢ 
                 S 
                 ⁢ 
                 
                     
                 
                 ⁢ 
                 
                   NR 
                   ⁡ 
                   
                     [ 
                     dB 
                     ] 
                   
                 
               
               = 
               
                 10 
                 × 
                 
                   
                     log 
                     [ 
                     
                       
                         
                           ( 
                           
                             
                               
                                 
                                   ( 
                                   
                                     a 
                                     + 
                                     1 
                                   
                                   ) 
                                 
                                 · 
                                 
                                   ( 
                                   
                                     s 
                                     - 
                                     a 
                                   
                                   ) 
                                 
                               
                               
                                 
                                   ( 
                                   
                                     
                                       
                                         P 
                                         ⁢ 
                                         
                                             
                                         
                                         ⁢ 
                                         2 
                                       
                                       
                                         P 
                                         ⁢ 
                                         
                                             
                                         
                                         ⁢ 
                                         1 
                                       
                                     
                                     - 
                                     a 
                                   
                                   ) 
                                 
                                 · 
                                 
                                   ( 
                                   
                                     s 
                                     + 
                                     1 
                                   
                                   ) 
                                 
                               
                             
                             - 
                             
                               
                                 a 
                                 + 
                                 1 
                               
                               
                                 s 
                                 + 
                                 1 
                               
                             
                           
                           ) 
                         
                         
                           - 
                           1 
                         
                       
                       · 
                       
                         B 
                         R 
                       
                     
                     ] 
                   
                   ⁢ 
                   
                       
                   
                   . 
                 
               
             
           
         
       
     
     
       25. The device of  claim 18 , wherein the correction table includes corrections for OSNR from five dB to thirty-five dB. 
     
     
       26. The device of  claim 18 , wherein the correction table corrects the measured OSNR to within 0.5 dB of an actual OSNR.

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