The electro-optic modulator is only 1-2cm long and its surface area is about 100 times smaller than traditional ones, the researchers say. It is also offers higher data transmission speeds with data bandwidth tripling from 35GHz to 100GHz, but with less energy consumption and ultra-low optical losses.
Electro-optic modulators convert high-speed electronic signals in computational devices such as computers to optical signals before transmitting them through optical fibres, but the existing and commonly used lithium niobate modulators require a high drive voltage of 3-5V. This is significantly higher than 1V, a voltage provided by a typical CMOS (complementary metal-oxide-semiconductor) circuitry. Hence, an electrical amplifier that makes the whole device bulky, expensive and high energy-consuming is needed.
The researchers believe they have overcome this problem with alithium niobate modulator that can be operated at ultra-high electro-optic bandwidths with a voltage compatible with CMOS.
"We show that by integrating lithium niobate on a small chip, the drive voltage can be reduced to a CMOS-compatible level," said Dr Cheng Wang of CityU. "In the future, we will be able to put the CMOS right next to the modulator, so they can be more integrated, with less power consumption. The electrical amplifier will no longer be needed.
"Remarkably," Dr Wang adds, "these tiny modulators can also support data transmission rates up to 210 Gbit/s."
The hope is this will pave the way for future high-speed, low power and cost-effective communication networks as well as quantum photonic computation.
