## 1 Introduction  
Metro access networks must provide a high data rate and bandwidth to keep pace with escalating bandwidth demands. The demand for triple-play services necessitates using a high number of distributed laser diodes at both the transmitter and receiver. There is growing evidence that an optical metro access network (OMAN) is a viable option for next-generation optical networks due to its low operating costs, big capacity, low latency, and high transmission efficiency [1, 2, 3]. Similarly, the convergence of wireless and optical technologies will facilitate the provision of large bandwidth for high data rates, improving service quality [4]. Different techniques are introduced to converge both the optical and wireless networks [5; 6]. As a meeting point between service providers and operators, OMANs are particularly well suited for adapting to the extreme acceleration of dynamics in optical systems, using efficient components like optical nodes and transponders [7; 8]. This means that these networks can quickly adjust to rapid changes in network conditions like traffic volume. Access and conventional convergence layers can be integrated into the metro access layer of the OMAN [9]. One accepted trend in the optical access network is merging metro and access structures under the cost-effectiveness paradigm to support many users [10]. However, new optical line terminals should be designed to support a large number of users. This allows for transparent reach between the metro network and the end-user. However, bridging optical access and metro networks requires a careful estimation of the deployment costs and power budgeting to facilitate the end-user with the guaranteed facilities [11]. Many researchers have widely deployed the ring topology in OMANs due to its self-healing characteristics and reliability for access networks [12; 13; 14]. [PERSON] et al. deployed a dual fiber ring structure for protection measurements and multiple transmitters at the optical line terminal side (OLT) [15]. Similarly, a ring-based OMAN network is deployed with two OLTs in [16] for protection purposes. The number of frequencies in an OMAN is rising in parallel with the country's increasing need for high-speed data transmission. Because of this, many light sources are needed to accommodate many users [15]. The OLT's price tag is critical in determining the final bill. It is possible to generate a wide range of frequencies from a single laser source using an optical multicarrier (OMC) generator [17; 18; 19]. The cascaded arrangement of a different or a single modulator is one of several recent ways of generating OMCs [20; 21; 22; 23]. The OMC is used in the optical access network [24; 22; 25], free space optics [26], in the OMAN [17; 27], and for other applications [28]. By boosting efficiency and simplifying maintenance, the OMC generators deployed in an OMAN can efficiently deliver a variety of frequencies. A spectrum-efficient network with an add-drop multiplexer and a centralized OMC source was utilized for the OMAN. Similarly, the carrier wavelength reuse concept was presented using an OMC-based ring network and a reconfigurable optical add-drop multiplexer [29]. In the provided references, some papers have proposed OMC-based sources as the best solution for an OMAN but did not provide detailed proposals of their OLTs [27; 30; 31]. In the OMAN, each user needs a specific wavelength, which increases the OLT's cost. A similar add-drop multiplexer has been used on the ONU side, but it is unable to drop many frequencies at once and is hence unable to handle the OMC source [31; 32; 33]. In the OMAN, in a core network, a ring architecture is an ideal topology for connecting different nodes, and an OLT is the main source for data handling/transmission to the ONUs. Therefore, for a ring-based architecture, two or more OLTs are tested in case a fiber failure occurs in the core network [16]. Hence, deploying more OLTs increases network costs.