graphene-based waveguide-integrated optical modulator.
UC Berkeley researchers have a graphene optical modulator down to 25 square microns in size — small enough to include in silicon circuitry — and modulated it at a speed of 1GHz. The researchers say that modulation speeds of up to 500GHz are theoretically possible, though — and for comparison, the modulators found in 40Gbit switches are measured in centimeters and operate at just 40GHz.
Professor Xiang Zhang, in an attempt to boil his group’s new findings into consumer-speak, puts it this way: “Instead of broadband, we will have ‘extremeband.'” — if graphene modulators can actually operate at 500GHz, we could soon see networks that are capable of petabit or exabit transmission speeds, rather than megabits and gigabits.
The smaller size means that thousands to millions of the graphene modulators could be used where one larger modulator was used before.