Abstract

Analog optical transmission techniques such as radio-over-fiber (RoF) and multiple intermediate-frequency-over-fiber (multi-IFoF) have attracted a great deal of attention for use in 5G mobile fronthaul links. Recently, an IFoF transmission with a record CPRI-equivalent capacity of 1.53 Tb/s has been demonstrated by using the Kramers-Kronig (KK) receiver. However, one major issue associated with the KK receiver is its computational complexity. Also, since the minimum phase condition must be satisfied, the optimal carrier-to-signal power ratio (CSPR) should be large enough; however, this results in a low receiver sensitivity. To address these issues, we have recently proposed and demonstrated a signal-to-signal beat interference (SSBI)-free direct-detection (DD) system employing phase modulation (PM). Since a PM signal has a constant amplitude, its SSBI term becomes just a direct-current (DC) component. Therefore, the SSBI can be perfectly removed using a DC block without resorting to complicated digital-signal-processing (DSP)-based schemes such as the KK algorithm. In this article, we describe the principles of operation of the SSBI-free PM system in detail. We present a numerical study of performance comparisons between the SSBI-free and KK systems. The result reveals that the optimal CSPR is always 0 dB in the SSBI-free system, while it depends on optical-signal-to-noise-ratio (OSNR) levels in the KK system. The dispersion tolerance of the SSBI-free system is also investigated, showing that the SSBI-free system can support a 2-GHz 1024QAM-signal delivery in a typical deployment scenario of mobile fronthaul links. Finally, we present an experimental demonstration of a 2-GHz 1024QAM OFDM transmission with the SSBI-free system. To the best of our knowledge, this is the first demonstration of 1024QAM DD-based transmission for analog mobile fronthaul links.

PDF Article

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription