As shown in Fig.3, the difference between the OSNR of odd-order and even-order Stokes lines decreases with the length of SMF 2 at 5 dBm BP power and 90 mW pump power. In Fig.3 (a), the
maximum difference between the OSNR of odd-order and even-order Stokes lines is 16.616 dB which is the largest among the three different situations. In Fig.3(b), the maximum difference is about 8.776 dB.