Optimization of arrayed waveguide grating-filteringresponse for efficient analog radio-over-fiber fronthaul over a wavelength-division multiplexing passive optical network

Wavelength-division multiplexing passive optical network (WDM-PON) is a promising solution to cope with the exponential data traffic growth, particularly regarding future mobile fronthaul. WDM-PON schemes, based on self-seeded wavelength agnostic transmitters using reflective semiconductor optical amplifiers (RSOAs), are seen as an option to provide an analog radio-over-fiber (A-RoF) alternative to the current digital fronthaul. Although these A-RoF have been already successfully demonstrated, it was observed that the arrayed waveguide grating (AWG)-filtering characteristics affect both the optical seed generation and the radio signal integrity, requiring a design optimization. In order to do so, in this article, we optimize the A-RoF transmission performance by comparing Bessel, Gaussian, and flat-top AWG-filter formats. The impact of seed linewidth and red-shift on the signal error-vector magnitude (EVM) and phase rotation is also investigated. We have found that EVM performance for BPSK and 16QAM transmission provided an improvement of 45% when compared to our previous results, with a phase offset of 0.8 degrees, indicating little to no distortion, as a result of the selection of the optimal AWG filtering response.