| 摘要 |
The power of an optical signal (s1) travelling on a channel (lambd1) of a WDM transmission system, is measured using a signature bit pattern (sBP1) which is inserted in the frame of the optical signal (s1). The power level of sBPL is adjusted at the launching point to a predetermined ratio (m) with the power of the optical signal. At a point of interest, the fiber is tapped and a fraction of the tapped signal, that includes a corresponding fraction of sBP1, is converted to an electrical signal. The fraction of sBP1 is extracted from a the electrical signal and power of sBPL is measured. This gives the optical power of s1 as (m) is known and also the calibration constant for the respective channel (lambd1) is known. The method can be applied for any and all channels of the WDM transmission system.
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