A　novel　technique　is　proposed　for　simultaneous　monitoring　of　optical　signal-to-noise　ratio　(OSNR)　and　chromatic　dispersion　(CD).　The　scheme　is　based　on　the　cross-phase　modulation　effect　in　a　highly　nonlinear　fiber,　which　induces　a　change　in　the　optical　tones　according　to　the　impairments.　The　power　ratio　of　the　optical　tones　at　two　separate　frequencies　is　utilized　for　monitoring.　Improvements　in　the　maximum　measurable　OSNR,　CD　and　dynamic　range　can　be　obtained　using　only　the　clock　tone　for　the　non-return-to-zero,　return-to-zero　with　a　50%　duty　cycle　differential　quadrature　phase-shift　keying,　differential　phase-shift　keying　and　on-off　keying　signals　at　80　Gb/s.　For　the　return　to　zero　differential　quadrature　phase　shift　keying　(RZ-DQPSK)　system,　the　OSNR　of　4–40　dB　can　be　monitored　with　a　36.73　dB　dynamic　range,　and　a　chromatic　dispersion　of　0–117　ps/nm　can　be　monitored　with　a　48.68　dB　dynamic　range.　A　correlation　is　built　to　describe　the　relationship　of　the　power　ratio　with　the　OSNR　and　chromatic　dispersion　which　has　a　root-mean-squared　error　of　1.41.　The　delay　group　dispersion　insensitivity,　the　impact　of　the　input　signal　power,　and　the　filter　selection　are　investigated.　The　design　enables　accurate　monitoring,　simple　operation　and　may　be　used　in　a　wide　range.　©　2023　Elsevier　GmbH