Optical links 1 – 100 metres in length require low cost, low power consumption
and small size. Vertical cavity surface emitting lasers (VCSELs) can be arrayed
inexpensively and can be directly modulated, avoiding the need for separate
optical modulator components. VCSELs operating at 850nm coupled to multimode fiber offer a compact and
inexpensive optoelectronic assembly, and are predominant for short reach optical communication. The key
challenge for the transmitter circuit in such systems is to modulate single-ended VCSEL currents up to about 10mA
at 25+Gb/s while maintaining bias voltages of approximately 2V across the VCSELs. At the receiver, a key
challenge is to provide adequate sensitivity using photodiodes with wide (50um) aperture and, hence, large
capacitance. Current commercial transceiver circuits are realized in SiGe BiCMOS, which is advantageous at both
the transmitter and receiver, but CMOS offers the potential for higher levels of integration and lower power
consumption. Our research efforts on low-power CMOS VCSEL drivers and optical receivers will be presented,
including several 65nm CMOS designs.

Speaker(s): Prof.Tony Carusone,

Location:
Room: B-314
Bldg: Polytechnique Montreal, principal building
Montreal, Quebec
h3t1j4