During use of the smart electrosurgical knife, deterioration of the diffuse reflectance spectroscopy (DRS) signal intensity obstructs proper distinction between tissues. In order to reduce signal loss, this research has focused on the influence of smart electrosurgery on both the morphology and composition of the layer covering the optical fiber tip. Optical microscopy (OM) and scanning electron microscopy (SEM) were used to examine the morphology, while energy-dispersive spectroscopy (EDS) and Raman spectroscopy (RS) were used to examine the composition. The results of these analyses showed that there are two factors, both caused by extreme tissue heat, leading to signal loss: first, the fiber tip gets soiled by a layer of tissue debris covering the tip, and secondly, the fiber tip gets damaged due to degradation of the acrylate coating. Therefore, two different surface modifications were tested: application of a polytetrafluoro-ethylene (PTFE) coating to prevent tissue debris adhesion, and stripping off the acrylate coating to prevent melting damage. Both modifications were unable to completely prevent signal loss. However, elimination of the acrylate coating has shown to reduce signal loss from 45.8% to 36.4%. In contrast, the PTFE coating has shown to slightly increase signal loss to 48.5%. According to this research, the optimal solution for signal loss during use of the smart electrosurgical knife should respond to thermal optical fiber damage and thermal tissue debris adhesion. Based on the research results, it is suggested to implement a heat-resistant optical fiber provided with an advanced heat-resistant, anti-adhesive coating.