This article introduces a method for detecting liquids over long distances that is based on measuring the difference in the detected reflected power from the end of a conventional single-mode fiber in different mediums. The power of reflected light is affected by the medium outside the fiber, as well as the maximum distance between the sensor end and the detector. The proposed approach was tested on a length of 3.01 km. An investigation of the greatest distance with commercially available laser diodes (MQW - DFB) and a PIN diode is provided; remote measurements at distances more than 34 km are theoretically possible in ideal conditions. We found that the usage of reflecting connectors is the primary constraint in obtaining theoretically calculated distances.

The Numerous papers have presented models for the mechanical reliability of optical fibres, or the lifetime of optical fibres, has been modelled in many works. Improvement of the mechanical and optical characteristics of standard single-mode fibres requires new tests and analyses. This paper provides an overview of scientific research into the mechanical reliability of optical fibres by some of the largest manufacturers. The investigation of the mechanical reliability and state of optical fibres after 20 years of real usage is the contribution of the paper, which concludes on its own. The contribution of the work is also in the analysis of the conditions under which optical cables - fibers were used. A prediction of the parameters limiting the lifetime of optical fibres was made based on the analyses that were conducted.

The main aim of the paper is modeling and simulation of fiber optic transmission. It also deals with ways to increase the capacity of fiber optic transmission links by using WDM (Wavelength Division Multiplexing) system. The parameters of the fiber optic transmission link were measured on a real optical transmission links and a model for simulation was set up. A simulation of increasing the capacity of a fiber optic transmission link was made in two ways. The first one is to increase the transmission speeds of the individual channels of the WDM system, and the second one is to increase the number of WDM system channels with lower individual speeds. The simulation results showed that the second method provides better quality of WDM service. The additional experiment was done on an existing ITU T G.655 optical fiber intended for WDM systems whose parameters were measured. Bit error rate and Q parameter for WDM system of 4 and 16 channel was used to check quality of proposed solution.

Fiber optics has revolutionized telecommunication with its superior bandwidth and distance it can span. For its use in IoT networks, some of the limiting factors are the high cost of new installations and the need to power the end device by electrical current. The installations are a part of long-term investments, and one can expect this to be an ever-smaller issue as more fibers are installed. Typically, the newly installed cables contain single-mode fibers. There are a lot of reports on transport of power over fiber, however, majority recommend using multi-mode fibers with a large core or double-clad fibers. In our approach, instead of increasing the core of the fiber, we focus on the possibility of shortening the working time of IoT devices, using the existing single-mode fiber for powering. Also, instead of an expensive PV (photo voltaic) cell with small dimensions and a high efficiency, we propose using the commercially available larger PV cells with an air gap between the end of the fiber and the cells. In accordance with our approach, we successfully conducted an experiment.

The Quality of Service (QoS) and the Quality of user Experience (QoE) are measures of the quality of satisfaction with the use of the service. The paper provides a detailed overview of QoS metrics applied by telecom operators in Bosnia and Hercegovina (BiH). Given that currently the focus of research is algorithms based on machine learning, which determine QoE, an overview of previous work in this field is given. The focus of the paper is an overview of activities on measuring QoS and QoE parameters performed by dominant telecom operators from Bosnia and Herzegovina.

Home installation is the shortest segment of FTTH (Fibre to The Home) networks. Despite this, it can also be a bottleneck of the whole network. This segment can produce a huge attenuation of optical signal. This paper deals with attenuation loss in home installations especially because of micro bending and attenuation of fusion splices caused by incompatibility of different fibre types.

ABSTRACT The first generation of installed optical cables in Eastern Europe has been in use for more than 20 years. This paper analyzes the change of optical fibers from the aspect of aging under the influence of transmitted signals and the aspect of parameter degradation during exploration. The paper provides the answer for how to repair the increased attenuation at 1310 nm. We also proposed the method of solution NG PON access for small remote villages that are situated along the analyzed route.

Changing the optical fiber parameters during long-term use can not be mathematically calculated. This paper analyses the change of optical fibers from the aspect of ageing under the influence of transmitted signals and the aspect of water influences. The analysis was carried out in such a way as to compare the measurements carried out after the installation of optical cables and measurements after 16 years of use. The analysis has been shown to vary greatly the loss of fiber optic splice for different wavelengths. These different loss for wavelengths 1310 nm and 1550 nm suggest that the loss of optical fiber has increased due to the impact of water.