A real-time pilot tone implementation allowing fronthaul monitoring and wavelength tunability in WDM-PON systems is experimentally demonstrated. The obtained results show transmission of a 128 kb/s control signal with minor impact on CPRI. 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.