Energy Efficiency of Optical Transceivers in Fiber Access Networks [Invited]

Road to Energy-Efficient Optical Access: GreenTouch Final Results

“…In particular, the traditional Gigabit Ethernet (GbE) local area network (LAN) interfaces are replaced by low power PtP optical transceivers. Conventional PtP optical transceivers operate continuously at a high and fixed optical power and the electronic-to-optical signal conversion efficiency is relatively low [15]. GreenTouch researchers have completely redesigned the transceiver and custom-built an application-specific integrated circuit (ASIC) prototype that minimizes the circuit power consumption for a target data rate up to 1 Gb/s.…”

“…The 2.5G repeater consumes 188.27 mW, and the two 1G eONTs 2*114.20 mW (values from power estimation tools applied to the chip design for CBI [30]). Because these values are not yet taking into account BAU improvements, the saving factor is obtained by dividing the sum of the aforementioned values by the baseline power for digital processing (1481.0 mW) P 5,HD = P 4,HD * 416.67 mW 1481.0 mW = P 4,HD * 0.281 (15) Secondly, the introduction of CBI makes the switching function in the ONU obsolete. When switching power (381.48 mW in the baseline) is subtracted from HGW processing power, we get P 5,HG = P 4,HG * 1900.0 mW − 381.48 mW 1900.0 mW = P 4,HG * 0.799 (16) As outlined in the architecture description in Section III-B, some of the network equipment is replaced and/or relocated when CBI is introduced.…”

Cost and energy efficient operation of converged, reconfigurable optical wireless networks

“…This can be achieved either utilizing energy efficient component development [15,16] or ONU sleep mechanism [17,18]. Power consumption for different transceivers are studied and demonstrated, using first-order energy modeling, energy efficiency is improved [15]. 10Gbps short cavity vertical cavity surface emitting laser (10G SC-VCSEL) ONUs is proposed in [16] for WDM/TDM PON architecture to utilize improved energy-efficiency.…”

“…In summary, the previous works [15][16][17][18][19][20][21][22] mostly focus on the energy savings in the WDM/TDM PON architectures and [22][23][24][25][26][27][28][29][30][31][32] proposes energy efficient studies in the FiWi networks by combining ONU sleep mechanisms with delay control schemes. It will be promising to introduce different CRMs that could enhance reconfigurable and service on demand converged access network with cost effective and energy efficient characteristics.…”

Energy-efficiency improvements for optical access

“…GreenTouch studies showed that the power consumption of a PTP transceiver at 1 Gbit/s can be reduced by more than an order of magnitude compared to a GPON transceiver (with 2.5 Gbit/s receiver and 1 Gbit/s transmitter) because of the reduced optical budget requirements. A PTP transceiver with an optimized transmitter and avalanche photodetector at 155 Mbit/s can even consume 70x less than a typical transceiver used in a GPON [8]. While operating at slower clock rates and lower laser currents, the PTP transceiver may use a simple low-voltage single-ended CMOS I/O driver, instead of the conventional current mode logic (CML) or low voltage differential signal (LVDS) which typically consume more power.…”