Software-Defined Optical Networking (SDON) signifies a revolutionary paradigm in optical network management and provisioning. It leverages the power of software-defined networking (SDN) principles to enhance the flexibility, efficiency, and intelligence of optical networks. In the realm of SDON, we introduce the Open Networking Engine (ONE), a groundbreaking application designed to optimize White box Reconfigurable Optical Add-Drop Multiplexers (ROADMs). ONE serves as a vital bridge between cutting-edge technology and real-world network orchestration. By harnessing device's YANG Models and the NETCONF protocol, it empowers network administrators with the ability to dynamically configure, provision, and monitor ROADMs. This paper not only highlights ONE's competency in the efficient management of network resources but also underscores the substantial potential of flexgrid technology, particularly in terms of spectral efficiency. The study also delves into the impact of channel bandwidth on critical network parameters, including packet loss, round-trip time (RTT), throughput, and TCP window size. The result is a noteworthy achievement, with a 93.4% improvement in spectral efficiency realized through comprehensive signal analysis. This research highlights the promising path toward enhancing optical network performance, fostering a more agile and resource-efficient network infrastructure.