Patent ID: 7379647

Claim:
A method, comprising: transmitting optical signals through a heterogeneous sequence of optical fiber transmission spans of an all-optical transmission line, each span having an optical transmission fiber connected to an optical amplifier, each amplifier being connected to launch the optical signals into a sequential remainder of the line; and wherein the transmitting comprises either launching the signals into highest loss ones of the fibers with substantially equal average optical launch powers or operating the spans with the highest loss ones of the fibers to have substantially equal quality products; and wherein the average optical launch powers are substantially equal to the inverse of a sum of (1−T j )γ j /[φ NL ·α j ] over the highest loss ones of the fibers, the parameters T j , γ j , and α j being the respective transmissivity, nonlinear coefficient, and loss coefficient of the fiber of the span indexed by j, the parameter φ NL being the cumulative nonlinear phase shift of the line, and each quality product is the per-span optical signal-to-noise ratio of the associated span times the nonlinear phase shift of the associated span.