Question Structure: Multiplexing $($MUX$)$ Part Introduction to Multiplexing: a$.$ Define multiplexing and its significance in optical communication systems. b$.$ Explain the concept of multiplexing in the context of combining multiple signals for transmission over a single optical fiber. Types of Multiplexing: a$.$ Differentiate between time division multiplexing $($TDM$)$ and wavelength division multiplexing $($WDM$).$ b$.$ Discuss the advantages of WDM over TDM in increasing the capacity of optical networks. Wavelength Division Multiplexing $($WDM$)$: a$.$ Define WDM and explain how it enables multiple signals to be transmitted simultaneously over a single optical fiber. b$.$ Describe the key components involved in WDM systems, such as multiplexers, demultiplexers, and optical filters. Principles of WDM Mux Part: a$.$ Explain the concept of wavelength channels and their allocation in a WDM system. b$.$ Discuss the role of mux part in combining multiple optical signals of different wavelengths into a single fiber for transmission. Characteristics and Performance: a$.$ Outline the key characteristics of a WDM mux part, including insertion loss, crosstalk, and channel spacing. b$.$ Analyze the performance parameters that impact the efficiency and reliability of the mux part in WDM systems. Applications and Future Trends: a$.$ Explore the applications of WDM mux parts in long$-$haul optical networks, data centers, and telecommunications. b$.$ Discuss emerging trends in WDM technology, such as dense WDM $($DWDM$)$ and coherent WDM$,$ and their implications for high$-$speed data transmission