A dual-rate (2 Gbit/s and 100 Mbit/s) optical transceiver designed for power-efficient connections within and between modern high-speed digital systems is described. The transceiver can dynamically adjust its data rate according to performance requirements, allowing for power-on-demand operation. Dynamic power management permits energy saving and lowers device operating temperatures, improving the reliability and lifetime of optoelectronic-devices such as vertical-cavity surface-emitting lasers (VCSELs). To implement dual-rate functionality, we include in the transmitter and receiver circuits separate high-speed and low-power data path modules. The high-speed module is designed for gigabit operation to achieve high bandwidth. A simpler low-power module is designed for megabit data transmission with low power consumption. The transceiver is fabricated in a 0.5 µm silicon-on-sapphire complementary metal-oxide semiconductor. The VCSEL and photodetector devices are attached to the transceiver's integrated circuit by flip-chip bonding. A free-space optical link system is constructed to demonstrate correct dual-rate functionality. Experimental results show reliable link operation at 2 Gbit/s and 100 Mbit/s data transfer rates with ∼104 and ∼9 mW power consumption, respectively. The transceiver's switching time between these two data rates is demonstrated as 10 µs, which is limited by on-chip register reconfiguration time. Improvement of this switching time can be obtained by use of dedicated input-output pads for dual-rate control signals.
© 2005 Optical Society of America
(200.0200) Optics in computing : Optics in computing
(200.4650) Optics in computing : Optical interconnects
(250.0250) Optoelectronics : Optoelectronics
(250.3140) Optoelectronics : Integrated optoelectronic circuits
Yongrong Zuo, Fouad E. Kiamiley, Xiaoqing Wang, Ping Gui, Jeremy Ekman, Xingle Wang, Michael J. McFadden, and Michael W. Haney, "Power-efficient dual-rate optical transceiver," Appl. Opt. 44, 7112-7124 (2005)