Communication
Fiber optics are widely used in telecommunications, so it's imperative to ensure that the cables used to carry the light signal are in good condition, to avoid altering the signal and therefore the information it carries. It is also important to know the optical losses of a fiber optic network, especially when the signal is transported over long distances. A complete characterization of this network can be carried out using OFDR technology. As a further application, this technology can also be used to measure the ping of a data center with remarkable precision.
The field of telecommunication is broad, and can also involve tiny objects such as a microchip of the order of 1cm², as shown in the figure opposite. Inside this waveguide, the light traveling through it is subject to various phenomena, notably reflection. OFDR technology offers ultra-fine spatial resolution for characterizing this type of component. In the example opposite, the entire spiral is up to a meter long. Note that the "path" highlighted in blue cuts the spiral over a distance of 2.6mm. Each time the spiral and this path cross, part of the light is reflected. Using OFDR technology, it is possible to characterize these reflections with a resolution of 52µm!
Thanks to this analysis (see below) of the component, we can see that over these 2.6mm (i.e. less than 0.3% of the total length) there are about fifty parasitic reflections.
Another application for one of our products in telecommunications is quantum cryptography. Polarization controllers are used to encrypt an information signal. This tool is capable of generating a random polarization state, and consequently a random quatic encryption key, in order to transmit information encoded in qubit form. This encryption key, transmitted to the recipient, will enable him, with the help of a polarization controller, to recover the original polarization state of the received signal and access the information it contains.