Energy-efficient 1060-nm optical link operating up to 28 Gb/s
An analysis of a 1060-nm VCSEL with a threshold voltage as low as 1.25 V and 3 dB frequency above 19 GHz in the 2.5 to 5 mA bias current range is presented. An optical link based on a custom-made 90-nm CMOS driver, low power VCSEL and 32-μm diameter photodiode is built and characterized. A 5.2 dB link margin is obtained with a 0.99 mW optical modulation amplitude and an 8.2 dB extinction ratio at 28 Gb/s. A 1.1 pJ/b transmitter power consumption is measured at 26 Gb/s. The platform that we use in the present study would be compatible with a wavelength division multiplexing scheme to reach high aggregate bitrate and channel density with low voltage, power and heat dissipation in a future optical module. Results clearly demonstrate the potential of VCSEL-based links to meet the requirements of next-generation exascale computers and data center systems.