Quantum internet works on Verizon's commercial fibre-optic network for the first time.

A ground-breaking experiment has been carried out in the US that could usher in a new era of digital communications. For the first time, it has been possible to transmit quantum data over commercial fibre optic cables, using the same internet protocol (IP) that all users of the global network are familiar with. Engineers from the University of Pennsylvania, in collaboration with the operator Verizon, demonstrated that quantum technology could interoperate with existing infrastructure and use the same standards as the classic Internet. A key element of this success was a miniature chip developed by the researchers, called the Q-Chip. It is this chip that enables the simultaneous transmission and coordination of classical and quantum signals. It made it possible to combine extremely sensitive quantum information with typical data transmitted over optical fibres, without the need for a completely new infrastructure.

Quantum signals are based on the phenomenon of entanglement between particles, which are so strongly interconnected that a change in one immediately affects the other, regardless of distance. This property could, in the future, allow quantum computers to be interconnected and create networks of unimaginable computing power. The problem is that quantum particles are very impermanent and simply measuring them results in a loss of information. Therefore, creating a working quantum network has so far been very difficult. The solution turned out to be to use a classical signal as a kind of 'conductor'. In the system developed by the team from the University of Pennsylvania, the classical light signal is transmitted just before the quantum signal. It can be safely read out and used for routing and data correction without disturbing the quantum state. It is as if a train is travelling with a locomotive at the front and closed carriages at the rear, the driver knows the route and encounters interference, but the contents of the carriages remain unaffected. The whole system works on the well-known Internet Protocol IP, which means that quantum data can be transmitted in the form of standard packets, identical to those that traverse the network on a daily basis. This is a huge advantage because there is no need to build the internet from scratch, just connect the new devices to existing fibre-optic cables. The Q-Chip also copes with interference, which is inevitable in real-world conditions. Unlike in a sterile laboratory, commercial fibre-optic networks are exposed to temperature changes, vibrations from the environment or even vibrations caused by transport and construction work. The chip can detect the effect of these disturbances on the classical signal and, on this basis, make appropriate adjustments to the quantum signal without the need to measure it directly, which would destroy the data.

During testing at the Verizon campus, the system operated over a distance of approximately one kilometre and achieved over 97 per cent transmission accuracy, confirming its resilience to the elements. Importantly, the chip was made of silicon and was created using technology that allows it to be mass-produced, similar to traditional processors. For the time being, the network was very simple and included only two buildings and one server, but expanding it does not require the creation of new infrastructure. All that is needed is to produce more chips and connect them to existing fibre optic cables. This opens up a real way to scale the technology quickly, at least at a city level. Of course, there are still major barriers. The biggest one is the inability to amplify quantum signals without destroying them. In the traditional internet, signal amplifiers are crucial for long-distance data transmission. Current systems used, for example, in so-called quantum cryptography already allow special 'quantum keys' to be transmitted, but they are not capable of connecting actual quantum computers into a single network. Nevertheless, the Pennsylvania experiment is a significant step forward. For the first time, it has been shown that quantum data can be transmitted using the protocols that govern today's internet and do so over the fibre optic cables currently in operation. If developments move in this direction, this technology could revolutionise the way we communicate and process information.

LED indicators in SIGNAL PRO multiswitches.

Multiswitches of the SIGNAL PRO series have been designed with the thinking of installer's convenience and reliability of the entire multiswitch installation. One of the important improvements is the use of LED indicators assigned to individual subscriber outputs.

With this solution, the installer is able to immediately assess the signal status of each output socket. In practice, this means that the correctness of the connections can be easily verified at the start-up stage of the installation and any irregularities detected - without the need for additional diagnostic tools.

The LED indicators act as a kind of 'control system', indicating the presence of a connected receiver (e.g. a satellite receiver, a TV with a built-in DVB-S2 tuner or a measuring meter). The lighting of an LED next to a given output clearly indicates that the circuit is active and correctly transmitting a signal.

LEDs in the SIGNAL PRO multiswitch.

If, on the other hand, the diode remains off with the device connected, it can be assumed with high probability that there is a problem in the installation. The most common causes are:

Such a solution significantly facilitates diagnostics and service, allowing to quickly locate the source of the problem, without the need for laborious checking of each element of the installation one by one. In addition, thanks to constant signal monitoring, users can be sure that the multiswitch operates stably and that satellite and terrestrial signals are distributed correctly to all rooms.

Why is calibration of a fibre optic splicer important?

Calibration of a fibre optic splicer involves adjusting the power and temperature of the arc generated to the current environmental conditions. A well-matched arc allows correct splices to be made - both in terms of attenuation and strength. Calibration should therefore always be carried out prior to the actual splicing operation, either at the start of the work or in the event of drastically changing conditions (e.g. a sudden drop in temperature due to the completion of splicing inside a building and further work outside).

The most expensive models of fusion splicers are equipped with pressure and temperature sensors that allow for an automatic calibration in real time. Most popular devices, however, require manual calibration, which will take several minutes. Skipping calibration will not always result in bad splices. However, there is a risk that some, even those indicating low attenuation, will be very weak and unstable mechanically (e.g. if the splicing temperature is too low, they may sometimes crack after an hour).

Signal Fire's AI-9 L5875, AI-5 L5872 and Sendun SD-9+ L5877 fibre optics splicers are based on a popular calibration method - fibres placed in the splicing chamber are subjected to successive electric arcs. The fibres are melted and the splicer software measures and analyses the distance over which the fibre faces retreat. Based on the measurement, the appropriate arc parameters are determined.

The Signal Fire calibration process is performed by selecting the 'Arc Calibration' option in the management application. Once the fibres are inserted into the splicing chamber and the lid is closed, the calibration process starts automatically. Once this is completed, the splicer switches to Normal mode, i.e. fibre splicing. On the Sendun splicer, this is available under the "Maintenence" icon - there is no need for a phone or additional app.

During the autumn and winter months, installers should pay particular attention to preparing their equipment properly before starting work. A welder that has spent the night in a car parked outside, when brought into a room with room temperature, is unsuitable for immediate work: fogged camera lenses can affect erroneous verification of fibre position and autofocus problems. To avoid this problem, the splicer should not be allowed to cool down.

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Model	Signal Fire AI-5	Signal Fire AI-9	Sendun SD-9+
Code	L5872	L5875	L5877
No. of motors	4	6	6
Zoom	x300	x300	x380
Min. splicing time	8	5	5
Min. heating time	18	15	11
Phone app	Yes	Yes	No
No of splices on 1 fully charged battery	160	240	320
Built-in VFL and OPM	No	Yes	Yes
Splicing presets	No	No	Yes - 41 presets
Touchscreen	No	No	Yes
Spare electrodes kit	No	Yes	Yes
Self-closing heater	No	Yes	Yes
Holder for sleeves cool down	No	Yes	Yes
Cleaver with auto-rotate function	No	No	Yes
Carrying and transport	Bag	Case	Case
USB port	No	No	No
LED diode	Yes	No	No
Smart functions (app)	Yes	Yes	No
Warranty time	3 years	4 years	4 years

How to power an IP video intercom and other devices at the same time using PoE?

In many installations, the problem arises how to simultaneously power an IP video intercom and another device requiring DC 12 V power (e.g. door opener, additional camera or other devices) from a single UTP cable via PoE.
The solution is to use any PoE switch (802.3af or PASSIVE) and the PoE stabiliser Atte ATTE SDIP-20-AD0S M18952. By connecting it to one port of the PoE switch, you can power both the video intercom and additional devices.
The stabiliser transfers power to the PoE output, while providing an additional output with a choice of 5 V, 12 V or 24 V, with a maximum output of 20 W. However, it is important to note that the total power requirements of all devices must not exceed the power limit available on the respective PoE switch port.
This solution reduces cabling and increases the flexibility of the installation, which is particularly useful in video door entry systems where it is often necessary to power several components from a single point.

Direct termination of fibre optic cables with a connector. Ultimode quick connectors are used for terminating fibre optic cables. They are an alternative to pigtail connections or SoC (Splice on Connector) connectors requiring the use of a fibre optic splicer. This solution will be ideal for CCTV, LAN and FTTH installations where maintaining connection attenuation below 0.1 dB is not a critical issue for the operation or reception of the installation. The actual attenuation of quick connectors at the level of 0.25 - 0.5 dB does not pose any obstacle to the realisation of typical point-to-point connections: switch - switch, camera - switch, media converter - switch, etc...>>>more

Video showing how to install the Ultimode ESC925T L5714 connector on a fibre optic cable

Signal Pro - pass-through multiswitches for small, medium and large installations