An optical storage system that receives an optical medium having a plurality of tracks for storing data, the system comprising: an optical head having optics that split a light beam into a higher power main beam and at least one lower power side beam (44, 48) that form corresponding spots (50, 54, 58) spaced along a selected one of the plurality of tracks; at least one controller coupled to the optical head that selectively positions the optical head for writing data along the selected one of the plurality of tracks using the main beam while reading data directly after writing from the selected one of the plurality of tracks using the at least one side beam, wherein a reflected beam associated with the side beam contains information associated with data marks immediately previously written by the main beam as well as the data currently being written by the main beam and a modulation noise canceller characterized in that the modulation noise canceller subtracts a signal associated to the data currently being written by the main beam from a read signal generated from the reflected beam; and in that the optical storage system comprises a correlation detector that determines similarity between the modulation noise-cancelled read signal and a write signal associated with the main beam that is time-shifted based on a transit time of the optical medium moving from the main beam to the at least one side beam to verify data written to the selected one of the plurality of tracks directly after writing, wherein the correlation detector combines the modulation noise-cancelled read signal and the time-shifted write signal and compares (172, 178) a resulting signal to an associated threshold to verify data written to the selected one of the plurality of tracks. an optical head having optics that split a light beam into a higher power main beam and at least one lower power side beam (44, 48) that form corresponding spots (50, 54, 58) spaced along a selected one of the plurality of tracks; at least one controller coupled to the optical head that selectively positions the optical head for writing data along the selected one of the plurality of tracks using the main beam while reading data directly after writing from the selected one of the plurality of tracks using the at least one side beam, wherein a reflected beam associated with the side beam contains information associated with data marks immediately previously written by the main beam as well as the data currently being written by the main beam and a modulation noise canceller characterized in that the modulation noise canceller subtracts a signal associated to the data currently being written by the main beam from a read signal generated from the reflected beam; and in that the optical storage system comprises a correlation detector that determines similarity between the modulation noise-cancelled read signal and a write signal associated with the main beam that is time-shifted based on a transit time of the optical medium moving from the main beam to the at least one side beam to verify data written to the selected one of the plurality of tracks directly after writing, wherein the correlation detector combines the modulation noise-cancelled read signal and the time-shifted write signal and compares (172, 178) a resulting signal to an associated threshold to verify data written to the selected one of the plurality of tracks.