Real-time demonstration of QoS guaranteed 25-Gb/s PON prototype with Ethernet-PON MAC/PHY and cost-effective APD receivers for 100-Gb/s access networks.

We demonstrate a real-time 25-Gb/s PON prototype with ethernet-PON MAC/PHY, O-band transmitter, and cost-effective APD receivers. With applying parasitic inductance and capacitance reduction, the frequency response of 25-Gb/s APD ROSA with TO46-pacakge is improved to support high receiver sensitivity around -25 dBm at the BER of 10-3. The 30 dB power budget of 25 Gb/s downstream is achieved at the BER of 10-3. With long-term ethernet packet transmission, 25 Gigabit and 10 Gigabit ethernet traffics are successfully transmitted through the 20-km SMF over 14 hour's observation window. Furthermore, QoS and bandwidth re-assignment function of the 25-Gb/s PON prototype are successfully demonstrated with respect to residential, business and mobile backhaul services in ONUs.

Compactly packaged monolithic four-wavelength VCSEL array with 100-GHz wavelength spacing for future-proof mobile fronthaul transport.

We report a cost-effective transmitter optical sub-assembly using a monolithic four-wavelength vertical-cavity surface-emitting laser (VCSEL) array with 100-GHz wavelength spacing for future-proof mobile fronthaul transport using the data rate of common public radio interface option 6. The wavelength spacing is achieved using selectively etched cavity control layers and fine current adjustment. The differences in operating current and output power for maintaining the wavelength spacing of four VCSELs are <1.4 mA and <1 dB, respectively. Stable operation performance without mode hopping is observed, and error-free transmission under direct modulation is demonstrated over a 20-km single-mode fiber without any dispersion-compensation techniques.

A WDM-PON with a 40 Gb/s (32 x 1.25 Gb/s) capacity based on wavelength-locked Fabry-Perot laser diodes.

We investigate a high capacity WDM-PON based on wavelength locked Fabry-Perot laser diodes. An error-free transmission of 1.25 Gb/s per subscriber was achieved with a flat-top passband AWG and a laser diode with low reflectivity. Then, we demonstrate a WDM-PON of 40-Gb/s capacity of 32 channels over 15 km of single mode fiber. It also shows that color-free operation within conventional C-band wavelength. The observed dispersion penalty after 30 km transmission was 0.5 dB. The demonstrated WDM-PON shows a robust transmission performance on the optical back reflection.

A multiple star WDM-PON using a band splitting WDM filter.

We propose a multiple star wavelength division multiplexing-passive optical network (WDM-PON) to serve several subscriber groups located at a widely distributed area. The architecture based on a band splitting WDM (BSWDM) filter separates upstream and downstream bands to several sub-bands and assign them to different subscriber groups. As a result, it enables to use a single type AWG for second stage splitting points. Thus, it provides color-free outside plant and simplifies management issues. The proposed architecture also provides pay as you grow feature.

A self-restorable architecture for bidirectional wavelength-division-multiplexed passive optical network with colorless ONUs.

We propose and experimentally demonstrate a novel protection scheme for wavelength-division-multiplexed passive optical network (WDM-PON) employing colorless optical transceivers. The proposed network employs 2 x N arrayed waveguide grating (AWG) to utilize its routing characteristics. The colorless operation is achieved by using wavelength-locked Fabry-Perot laser diodes (FP-LDs) injected with spectrum-sliced amplified spontaneous emission (ASE) light. The experimental results show that the restoration can be achieved within 8 ms against the feeder fiber fault and the power penalty introduced by the restoration process is negligible.

Adjacent crosstalk suppression in a colorless WDM passive optical network.

We propose and experimentally demonstrate a novel wavelength-division- multiplexed passive optical network (WDM-PON) scheme for the suppression of adjacent crosstalk arising from the wavelength misalignment in arrayed waveguide gratings (AWGs) between a central office (CO) and a remote node (RN). The adjacent crosstalk suppression is achieved by allocating two different bands to adjacent channels of the AWGs by utilizing interleavers and WDM filters. The transmission performance of the proposed scheme was measured at a 155 Mb/s data stream, and error free transmission with a power penalty less than 0.7 dB was successfully achieved in case of AWG misalignment of 0.3 nm.