In an era where buildings are increasingly becoming multifaceted entities, the paradigm of smart buildings has witnessed significant evolution. This advancement integrates sophisticated communication technologies, the Internet of Things (IoT), artificial intelligence (AI), and data analytics. Intending to design an effective smart building monitoring system, this research paper explores and compares various solutions for measuring building parameters by identifying a broad spectrum of review articles considering building occupant behavior, sensor deployment, and implementation complexity. The objective of our paper is to compile diverse information on various sensors used for monitoring building conditions and provide a comprehensive overview of data structuring and processing, all within a single article. Additionally, this paper addresses the challenges of combining data from decentralized systems and the need for managerial tools to optimize user experiences. The findings contribute to the advancement of smart building management, offering valuable insights for improving building performance and user experience as well as evaluating future research directions in this field. This review is designed to serve as an introduction for anyone venturing into the field of building monitoring.

Optical Fiber Communication widely implements Dense Wave Division Multiplexing (DWDM) technique in order to accommodate large number of channels within a limited bandwidth. But, this technology suffers a serious degradation in signal quality due to inter-channel interference. Optical Kerr Effect, in addition to this, worsens the situation. This paper deals with minimization of Four Wave Mixing (FWM) impact, one of the Optical Kerr effects, by using variable channel spacing instead of conventional fixed channel spacing technique. FWM effect generates spurious components at multiple frequencies, whose effective amplitude can be reduced using different channel spacing. Bit Error Rate (BER) observed for different length of fiber has been analyzed with an aim to estimate the difference between variable channel spacing algorithms. Obtained results have shown that BER of 10-11 can be reached with 153.7 km long fiber for fixed channel spacing while the usage of variable channel spacing method keeps the same BER level with 160.5 km long fiber.

In this research we investigated the performance of in-line Erbium Doped Fiber Amplifier (EDFA) in 40 Gbit/s 8 channels wavelength division multiplexing (WDM) transmission system with NRZ-OOK modulation format and 100 GHz channel spacing. Different EDFA configurations: co-propagation (980nm) and counter propagation (1480nm) were used in order to find an optimal settings with minimal noise factor indicators. Results show that in general the pumping wavelength of 980nm gives a stable noise factor values within 4 - 4.5 dB both for 10m and 30m long fibers. With the increase of pump power and fiber length, counter-propagation at pumping wavelength of 1480nm provides noticeably high noise up to 9-15 dB.

The paper presents experimental study of the major erbium-doped fibre amplifier (EDFA) features such as gain at low signal and gain saturation by an application of different erbium-doped optical fibres (EDFs). The main objective of the research is to estimate how the performance of EDFA varies depending on the length of doped fibre, pumping configuration scheme, as well as excitation source power. It is shown that a high gain coefficient of 16–20 dB can be practically achieved.

In this paper, nonlinear nature of three different optical fibers: Corning SMF-28 ultra optical fiber, Draka enhanced single-mode optical fiber and highly nonlinear fiber has been studied experimentally by the measurement of nonlinear coefficient using four wave mixing process. Obtained results have shown that measured values of the nonlinear coefficient are 0.78 W^-1km^-1 for SMF-28 fibers, 1.45 W^-1km^-1 for enhanced singlemode fiber and 10.68 W^-1km^-1 for highly nonlinear fiber, that conforms to typical values.

WDM transmission system capacity growth creates a need to increase EDFA output power. One of the most attractive solutions in this area is the usage of ytterbium doped fiber (EYDF), which ensures low non-linearity, without affecting the amplification efficiency. In this research master-oscillator power amplifier (MOPA) was modelled using different ytterbium co-doped fiber lengths: 10, 15, 20 and 25m and pumping at 975 nm wavelength. Obtained results have shown the usage of 10m and 15m long ytterbium co-doped fibers ensures stable and significantly high output power values up to 4 W with pretty low noise factor which stays is in range of 5 dB.