English to Russian Science Physics оптика

Although the back-to-back OSNR requirements are shown here for a fixed data rate of 40 Gbit/s, they can also be scaled to other data rates. When quadrupling the data rate, for instance, the fourfold amount of noise power falls into the detection bandwidth and the fourfold signal power PR X,avg is required at the receiver input to obtain the same BER. With the OSNR definition of (7.1), this corresponds to a required OSNR which is 6 dB higher. Alternatively, the system noise performance can be expressed in a form that is independent of the data rate by illustrating the 164 7 Back-to-Back and Single-Span Transmission BER with respect to the SNR defined in (6.30). In that case, the relative distances between the curves of different modulation formats change.