Patent ID: 7436582

Claim:
A bidirectionally-pumped Raman amplifier that is responsive to an optical signal over an optical fiber facility of an optical fiber system, the optical signal having N optical signal channels, comprising: at least one backward optical pump configured to inject backward optical power by a counter-propagating signal-pump optical interaction with the optical signal; M forward optical pumps configured to inject forward optical power by a co-propagating signal-pump optical interaction with the optical signal; a measurement unit configured to determine an input signal power variation for at least one wavelength region, the N optical signal channels being associated with K wavelength regions, K being at least one; a control unit configured to: determine a fixed backward pump power value for the at least one backward pump; and determine a forward pump power adjustment for least one forward optical pump using a predetermined function that depends on the input signal power variation; the at least one backward optical pump configured to adjust a backward pump power output in accordance with the fixed backward pump power value; the at least one forward optical pump configured to adjust a forward pump power output in accordance with the forward pump power adjustment; and the predetermined function comprising: Δ ⁢ ⁢ P d ⁡ ( j ) ≈ ∑ K k = 1 ⁢ T d ⁢ ⁢ L ⁡ ( j , k ) ⁢ Δ ⁢ ⁢ S L ⁡ ( k ) , wherein k corresponds to a k th wavelength region, wherein j corresponds to a j th forward Raman pump, ΔS L (k) corresponds to the input signal power variation for the k th wavelength region as linearly scaled, ΔP d (j) corresponds to the forward pump power adjustment of the j th forward Raman pump as logarithmically scaled, and T dL (j,k) corresponds to a linear coefficient relating the forward pump power adjustment of the j th forward Raman pump and the input signal power variation for the k th wavelength region.