The problem with IR laser comms is its only p2p, LoS, meaning its only practical fixed end points. A nice complement may be possible in the near UV (200 - 350nm, with a peak at about 250nm) by using only the molecular vibrational modes of ozone. Due to atmospheric aerosols beams at these frequencies.aimed at low-to-mid angles can be sufficiently dispersed so as to enable no-LoS. Due to the upper atmosphere ozone these frequencies are greatly darked in most areas of the globe even at noon. On Wed, Jun 23, 2021 at 5:21 AM grarpamp <grarpamp@gmail.com> wrote:
https://phys.org/news/2021-06-quantum-cascade-lasers-private-free-space.html
Quantum Key Distribution QKD and the ridiculous cost and waiting time for this paper tech is totally unnecessary for building your own guerilla meshnets p2p among your neighbors reaching around the globe right now TODAY.
Just one year of payments to your shitty cable/dsl ISP you can build a simple box with two NICs to each of two neighbors for a redundant mesh path... copper, fiber, RF, laser, etc. Literally under $750 one time HW will last you not one year but 10 years, under $10/month. Peer every 100 nodes with outside internet for $0.20/Mbit/month until your meshes can span 1000's of km to be your own complete p2p tier-1 meshnets. You already have strong opensource crypto to independently encrypt every p2p link using PSK, rotation, quantum-safe algos, etc.
BTW, all ISPs up through Tier-1's refuse to independently encrypt and pad each physical link because they love spies and spying. They won't encrypt the physical links, your meshnet will.
It costs so little to build it yourself eliminating middleman ISP that there's great small business profit to be made selling the boxes and copper, fiber, laser, RF gear to those who want to link up to the mesh but can't follow the self-HOWTO.
And it's a great meetup to spread cryptoanarchy, cryptocurrency, etc.
WiFi routers
Consumer WiFi schemes suck at reliably moving bandwidth 24x7 and are a channel allocation and interference nightmare and should not, certainly not without directed antennas, be used for building a real p2p one-owner-per-node meshnet unless you have no other means to reach a peer node directly over copper, fiber, laser, guerilla UWB RF, etc. And if you still can't reach, then encrypt and tunnel it over cable/dsl ISP until you can.
WiFi routers should have incorporated ability to communicate between nearby units. The vast majority of WiFi routers are within hearing distance of other routers.
Some WiFi can do raw mode or at least ad-hoc, but the problem is it's all omnidirectional over the same limited spectrum... too many speakers, too much density, too much power to override others, all broadcast, plus all the owners who give zero shits about coordinating a plan with anyone else because they're not in it to do a common goal of p2p meshnet, they just want to blast their phones and laptops to their ISP screw their neighbor, and good luck trying to talk to them about channel allocation/power you see via your analyzer... so without a common meshnet project such WiFi ends up being a race to spam itself to death.
With a guerilla p2p meshnet around the world, you're specifically engineering to build the most reliable interference-free distributed-ownership encrypted fastest direct p2p-node links you can.
" Free-space optical communication, the communication between two devices at a distance using light to carry information, is a highly promising system for achieving high-speed communication. This system of communication is known to be immune to electromagnetic interference (EMI), a disturbance generated by external sources that affects electrical circuits and can disrupt radio signals. While some studies have highlighted the possible advantages of free-space optical communication, this system of communication has so far come with certain limitations. Most notably, it is known to offer limited security against eavesdroppers. Researchers ... have recently introduced a unique system for more secure free-space optical communication based on a technology known as quantum cascade laser, a specific type of semiconductor laser that typically emits mid-infrared light. "The core idea behind our research is that private free-space communication with quantum key distribution (i.e., based on quantum physics properties) is promising, but it is probably years away, or even further," ... "Currently, the main limitations of this technology are the requirements for cryogenic systems, very slow data rates and costly equipment." Colleagues propose an alternative to previously proposed systems for achieving private free-space communication, which implement a cryptographic protocol based on the laws of quantum mechanics. The new system they devised is based on the use of two uni-directionally coupled quantum cascade lasers. The researchers' approach combines what is known as chaos synchronization with the mid- infrared wavelength of quantum cascade laser technology. Chaos synchronization is a specific property that has been examined in the context of semiconductor lasers for decades. "Chaos synchronization is the key to private communication, while mid-infrared wavelength means that the attenuation of the atmosphere is low in comparison with near-infrared wavelength, where most of the semiconductor lasers emit," Spitz explained. "We can thus envision transmission with a very long range and with immunity to the atmospheric conditions. Moreover, the mid-infrared wavelength implies stealth, as the background radiation is in the same wavelength domain." The mid-infrared wavelength of the quantum cascade lasers makes it even harder for a potential eavesdropper to decipher information exchanged using the researchers' system. This means that the security of communications is increased further. "I feel the most notable achievement is the successful chaos synchronization between two QCLs," Spitz said. "For a long time, the possibility to generate temporal chaos in this type of structure was controversial because they rely on a different technology, in comparison with most of the semiconductor lasers, which overall makes QCLs more stable, so not really prone to chaos. A few years ago, we experimentally demonstrated that QCLs can generate temporal chaos, and we now took this one step further by achieving private communication based on chaos synchronization." So far, the researchers merely described a proof o concept of their proposed system, where the distance between the two quantum cascade lasers is merely of one meter. This is not a realistic configuration for free-space communication. However, they hope to improve their system, to make it more suitable for real-world implementations. "We plan to increase this distance to hundreds of meters, then kilometers, in order to build an operational system," Spitz said. "Apart from quantum cascade lasers, there are other mid- infrared semiconductor lasers, such as interband cascade lasers (ICLs). We plan to repeat the same experiment with ICLs, to determine the best configuration for private communication at mid- infrared wavelength." More information: Private communications with quantum cascade laser photonic chaos. Nature Communications(2021). DOI: 10.1038/s41467-021-23527-9. "