Optical communication systems with wavelength reuse are systems in which a single wavelength is used for transmitting and receiving information over a single optical fiber. In such systems, the information encoded in the amplitude of an optical signal arriving at a terminal has to be erased before the signal is amplified and remodulated with new information. The doubling of bandwidth efficiency offered by wavelength reuse architectures is of special interest in wavelength division multiplex passive optical networks (WDM-PON) with wavelength-agnostic transceivers. Some of the desired features of such wavelength reuse systems include broadband operation, protocol transparency and passive operation, while one of the main challenges is preserving wavelength information through data erasure. This work describes the first demonstration of a wavelength reuse WDM-PON system in which the data erasure is accomplished by passive optical modulation averaging. To this end, several transceiver architectures were investigated: light was amplified using injection-locked Fabry-Pérot laser diodes (FP-LD) and semiconductor optical amplifiers, while remodulation was performed by either direct and external modulation. Best performance was demonstrated with RSOA architecture at a data rate of 1.25 Gbps and link length up to 30 km. The investigated architectures are inherently wavelength agnostic and can be employed in any intensity optical modulation. The modulation averaging structures were investigated for their depolarizing potential and use with coherent light.