title: Power-efficient dual-rate optical transceiver.
abstract: 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 microm 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 approximately 104 and approximately 9 mW power consumption, respectively. The transceiver's switching time between these two data rates is demonstrated as 10 micros, 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.
authors.affiliation: Department of Electrical and Computer Engineering, University of Delaware, 114 Evans Hall, Newark, Delaware 19716, USA. zuo@ece.udel.edu
authors.forename: Yongrong
authors.initials: Y
authors.lastname: Zuo
authors.forename: Fouad E
authors.initials: FE
authors.lastname: Kiamiley
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Wang
authors.forename: Ping
authors.initials: P
authors.lastname: Gui
authors.forename: Jeremy
authors.initials: J
authors.lastname: Ekman
authors.forename: Xingle
authors.initials: X
authors.lastname: Wang
authors.forename: Michael J
authors.initials: MJ
authors.lastname: McFadden
authors.forename: Michael W
authors.initials: MW
authors.lastname: Haney