# High speed data transfer over a fiber optic cable

Can someone please explain how can we transmit very high speed data (e.g. $10~\rm Gbps$) over fiber optics, knowing the fact that the wave that travels through the fiber is an optical wave (in the Infra-red region), which only has a wavelength of about $1550~\rm nm$ ($645~\rm MHz$) ? In other words, if our information is only able to transmit over a wave that has a frequency of $645~\rm MHz$, be able to achieve a data rate of $10~\rm Gbps$?

• How do you get a frequency of $645 \text{ MHz}$ for light with wavelength $1550 \text{ nm}$? Using $f = \frac{c}{\lambda}$ where $\lambda$ is the wavelength and $c = 3 \times 10^8 \frac{m}{s}$ I get the frequency of $1550 \text{ nm}$ light to be $f = 193 \text{ THz}$. – jgerber Feb 5 '18 at 7:29
• Also the bandwidth doesn't depend on the frequency of the carrier - but on the bandwidth of the system that modulates it and detects it. – Martin Beckett Aug 2 '18 at 23:47