A flexible grid optical transceiver communicatively coupled to an optical network includes a coherent optical transmitter configured to generate a transmit signal at a first frequency/wavelength center and spanning a first one or more bins of optical spectrum; and a coherent optical receiver configured to receive a receive signal at a second frequency/wavelength center and spanning a second one or more bins of optical spectrum, wherein a size of each of the first one or more of bins and the second one or more of bins is based on a required roll off of a wavelength selective component in the optical network.