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 <grarp...@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. > " >
