Sir i constructed the code like this : if code is 10101010 , then if first wavelength is 1550.1 and bandwidth is .3, the next would be 1550.7nm , though know i think that the steps and the bandwidth have no relation with each other ( as seen from the image that i sent yesterday that was sent by the authors of the paper) they have used 1550 , 1550.5 , 1551 ( say for 11110000) while bandwidth is 0.3 nm