The IEEE Std 802.3ba-2010 for 40 Gb and 100 Gb Ethernet was released in July, 2010. This standard will continue to
evolve over the next several years. Two of the challenging transmit/receive architectures contained in this standard are
the 100GBASE-LR4 (<10 km range) and 100GBASE-ER4 (<40 km range). Although presently envisioned for 1310 nm
optical wavelengths, both of these 4 lane, 25.78 GBaud formats may be adopted for the impending 850 nm short reach
optical backplane market, whose range is below 150 m.
Driven by major computer server companies, such as IBM, HP and Oracle, the 850 nm Active Optical Cable (AOC)
market is presently undergoing an increase of serial rates up to 25 Gbaud to enhance backplane interconnectivity. With
AOCs up to 16 channels, the potential for up to 400 Gbps backhaul composite data rates will soon be possible.
We report a 25 Gbps photodiode with quantum efficiency ~ 0.6 at 850 nm. This InGaAs/InP device was optimized for
high quantum efficiency at 850 nm. When pigtailed with multimode fiber and integrated with an application-specific RF
amplifier, the resultant photoreceiver will provide multiple functionalities for these 100 Gb Ethernet markets.