A wavelength tunable device for use in a wavelength division multiplexing (WDM) system comprising a display device for displaying at least one operating wavelength of the wavelength tunable device. The display device is electrically coupled to a control unit in the wavelength tunable device so as to display the tuned wavelength in real time. The wavelength tunable device may be, in exemplary embodiments, an optical transponder, wavelength division demultiplexer, or wavelength division multiplexer. In embodiments where the optical equipment has a plurality of tunable ports, the display device is adapted to display the operating wavelength of each tunable port.