Experimental comparison of simultaneous transmission of LTE-A multi-band and gigabit/s 4-PAM signals up to 50 m of large-core graded-index POF

This paper reports the experimental results of the co-transmission of a multi-band LTE-A and gigabit/s baseband 4-PAM signals over 35 m and over 50 m of 1 mm core diameter PMMA GI-POF, using low-cost components. Both links used a red light 650nm laser diode and p-i-n photodiode with transimpedance amplifier. The 4-PAM transmission achieved 1.2 Gb/s (BER<1×10
⁻³
) for both the 35 m and the 50 m links, together with 8 LTE-A standard-compliant bands with EVM<8%. The LTE-A signal was chosen as 5G-like signal, and the LTE-A bands were transmitted with a radio-over-fiber technique, without frequency up and down conversion. A gain control technique by using the LTE-A digital amplifier was provided to avoid optical transmitter saturation. Digital filtering was employed on both the transmitter and receiver sides to improve the spectrum allocation of the 4-PAM and LTE-A signals. Optimization of the receiver amplifier gain enabled adequate co-transmission over GIPOF lengths from less than 35 up to 50 m, thus resulting in a reliable and inexpensive solution with a flexible link reach for creating in-home femtocells.