A 80 km reach fully passive WDM-PON based on reflective ONUs

Abstract

We propose a novel line coding combination (Inverse RZ coding in downlink and RZ in uplink) that extends the reach of WDM Passive Optical Networks based on Reflective SOAs with no in-line amplification. We achieved full downstream remodulation even when feeding the reflective SOA with power levels as low as -35 dBm, thus increasing the system power budget. We experimentally assessed this scheme for a fully passive, full-duplex and symmetrical 1.25 Gb/s WDM-PON over a 80 km G.652 feeder.

L-band in-line remote amplification for an extended WDM/PON ring architecture

“…A power value of -20 dBm is considered necessary in order to both obtain the downstream data and at the same time use the optical carrier for modulation with the upstream signal and achieve an output of 0 dBm. Transmission with low input powers have been already demonstrated [5]. Finally the receiver at the OLT is considered to have a sensitivity of -28 dBm.…”

Semiconductor optical amplifiers in access networks

“…The RSOA can be seeded either by CW light originating from the OLT, or by using an appropriately coded down stream signal [15]. The high off-state extinction provid ed by the SOA is essential for preventing in-band crosstalk penalties at high split ratios [16].…”

Enabling In-Band Bidirectional OFDM-Uplink and OOK-Downlink Transmission in Long-Reach RSOA-Based WDM-PON Systems

“…However, the former requires sufficient injection power while the latter is polarization dependent, and both have a certain sensitivity to back reflection along the fiber. Another approach gaining lots of attention and showing great potential is the use of reflective semiconductor optical amplifier (RSOA) at the ONU for carrier reuse scheme [11]- [18]. The principle of these schemes is to erase the DL modulation and reuse the reflected carrier for UL transmission, making the ONU very simple.…”

“…A phase modulated DL signal was proposed in [13]; different or overlapped spectral locations for DL and UL was studied in [14]. Other approaches used two separate fibers for DL and UL [15], transmitted pass-band signals [16], time-division multiplexing [17], or tailored returnto-zero format [18]. These schemes, which require sophisticated receivers for DL signals, are less attractive for a low-cost ONU.…”