This read-only CoriantTypesOpticalDB value reports the current Q-factor of the coherent optical channel (och-os) on the line side of a pluggable transceiver, a single-number measure of signal quality that correlates with the expected pre-FEC bit error ratio of the coherent channel. An administrator uses Q-factor as a quick at-a-glance health indicator for the optical channel, since it summarizes overall signal quality without needing to interpret bit-error-ratio figures directly. For example, a steadily declining Q-factor reported on och-os would be treated as an early warning of channel degradation worth investigating before the pre-FEC bit error ratio actually crosses into a service-affecting range.