Patent ID: 11879803
Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 4:
5. The optical fiber testing device according to claim 4, wherein the measuring instrument
allows probe light and pump light having a given wave number to enter the optical fiber to be measured for each of the propagation modes, thereby obtaining a Brillouin Frequency Shift amount;
allows probe light and pump light having a different wave number different from the given wave number to enter the optical fiber to be measured for each of the propagation modes, thereby obtaining a Brillouin Frequency Shift amount; and
determines a difference between the Brillouin Frequency Shift amount for the given wave number and the Brillouin Frequency Shift amount for the different wave number for each of the propagation modes, as the change amount.