# Optical Technologies Supporting 5G/6G Mobile Networks
## 2 An Overview of Published Articles
Experiments were performed for 10, 20, and 30 candidate paths, and the effectiveness of the Automatic Hidden Lightpath (AHL) method was presented based on the bandwidth blocking probability (BBP) metric as a function of Traffic Load (TL). The effectiveness of AHL refers to the situation when all optical resources are visible at the level of the logical IP layer. Simulation experiments performed in two node selection scenarios clearly show that an increase in AHL candidate paths significantly reduces the BBP value. The previously mentioned flexible EON networks require optical equipment that allows for quick software change of the physical parameters of the optical signal. This necessity results from the need for more effective use of an optical channel with a specific spectral width when the distance between the transmitter and the receiver has changed. Such a need may arise, for example, from the need to reduce the delay because the service provided via the edge cloud to the 5G/6G mobile network requires maintaining the so-called real time. In order to meet this request, one of the methods will be to establish a connection at the optical layer using several transceivers located closer to the service recipient. Transceiver inserts or optical cards supporting different bitstreams with fixed granularity will greatly increase the flexibility of lightpath selection. This task can be achieved on the optical side when the modulator is complex and reconfigurable enough to be able to change the modulation method on the fly to suit the quality of the optical link and the bitrate demand. In the third paper, authored by [PERSON] et al. and titled \"A Novel Reconfigurable Nonlinear Cascaded MZM Mixer, Amplitude Shift Key Modulator (ASK), Frequency Hopping and Phase Shifter\" [32], the authors proposed a solution for the optical system built on two single-arm Mach-Zehnder Interferometers (MZIs). The proposed design allows the MZI mixer optical system to be introduced into a specific functional state (Amplitude Shift Keying (ASK) modulator, Frequency Hopper (FH), Phase Modulation (PM) shifter). The proposed solutions do not allow for a significant change in the order of optical modulation, but they are a good introduction to the construction of such systems. Selecting any of the mentioned functions does not require hardware reconfiguration; all reconfiguration parameters pertain to the electrical states of the control signals, i.e., Radio Frequency (RF) and Local Oscillation (LO). The experiments were carried out at frequencies no higher than 20 GHz. It has been shown that the use of the nonlinear characteristics of the MZI system enables effective control of the transformation of the microwave photonic (MWP) signal in terms of frequency, amplitude, and phase. Compared to microwave (MW) systems, MWP systems are primarily characterized by a much wider bandwidth, which has drawn special attention. Other optical networks that allow for connecting components of 5G/6G mobile systems are passive optical networks (PONs). Currently, these networks constitute a very important access link between the wide area network and end subscribers. The capacity of modern passive systems and networks is becoming so large that they can and should be used to connect various components of industrial, urban, and infrastructure networks. PON's support for current- and next-generation mobile systems may primarily consist of connecting the 5 GC network with the NG-RAN via backhaul (BH), but the implementation of transmission tasks in the fronthaul (FH) and midhaul (MH) domains is also very important. The difference in these transmission services is that backhauling may require long transmission distances exceeding 100 km, while in FH/MH networks, the path length does not exceed 20 km. The fourth paper, authored by [PERSON] et al.