针对现有光纤无法满足宽带光密集波分复用系统传输和S+C+L波段粗波分复用的要求，设计了一种具有中心凹陷的三角形芯+环形的折射率剖面，利用外部气相沉积工艺制备了一种非零色散位移光纤，并通过调整第一芯层的相对折射率和第二芯层与第一芯层的半径比，探究了其对光纤衰减、色散斜率和有效面积等参数的影响。研究发现，当第一芯层的相对折射率逐渐增大且第二芯层与第一芯层半径比逐渐减小时，零色散波长和有效面积逐渐减小。当第一芯层的相对折射率在0.52%~0.53%，芯层半径比在2.6~2.7时，光纤的有效面积接近70 μm²，零色散波长在1 420 nm附近，在1 550 nm波段的色散系数大于8 ps·nm^-1·km^-1，色散斜率为0.059 ps·nm^-2·km^-1，可以较好地抑制传输过程中光非线性效应，满足长途干线网与城域网的使用要求。

Existing optical fibers struggle to support broadband dense wavelength division multiplexing and coarse wavelength division multiplexing transmissions, necessitating the development of optimized fibers with moderate dispersion, low dispersion slope, enlarged effective area, and low attenuation. Currently, None Zero Dispersion Shifted Fiber (NZDSF) fibers have a small effective area incompatible with conventional fibers, emphasizing the need for precise design control of the refractive index profile. Therefore, creating a S+C+L band NZDSF with a large effective area and low slope is crucial for meeting the escalating demand for bulk data transmission.The dispersion slope, a crucial parameter in optics, is determined by the interplay between waveguide and material properties. The effective area, a metric that signifies the fiber's optical performance, relies heavily on the refractive index profile and the chosen input wavelength. In order to find the appropriate dispersion slope and effective area, we need to find a suitable refractive index profile. In our research, we have employed a refined profile structure modal, featuring a triangular+ring core configuration embellished by a central depression and fabricated by a two-step process to prepare the core and cladding by using the Outside Vapor Deposition (OVD).Through experiments, adjustments were made to the doping levels in the core, thereby modifying the relative refractive index Δn₁ and radius R₁ of the first core layer. This enabled the formation of a triangular cross-sectional structure. Simultaneously, the relative refractive index Δn₃ and thickness R₃-R₂ of the third core layer were also adjusted, resulting in distinct refractive index waveguide configurations. This approach strucks a balance between achieving low attenuation, a large effective area, a reduced dispersion slope, and an appropriate zero dispersion wavelength. After optimizing the preform preparation and drawing process, the optical fiber cross-section obtained has a high matching with the designed cross-section. The triangular structure of the first core layer has a relatively straight slope, and Δn₁ is between 0.52% and 0.57%. In the third core layer, a slightly curved convex structure is formed due to the diffusion of GeO₂, and Δn₃ is between 0.13% and 0.17%. In line with the experimental findings, it has been observed that when the first core layer radius R₁, the third core layer R₃, and the second core layer's relative refractive index Δn₂ remain relatively constant, an increase in Δn₁ and a subsequent decrease in R₂/R₁ lead to a gradual reduction in the zero dispersion wavelength λ₀ and a corresponding decline in the effective area A_eff. Our experimental target is to achieve a zero dispersion wavelength λ₀ below 1460 nm, even approximating 1 420 nm, while maintaining a significant effective area A_eff. To balance these parameters, it is necessary to slightly reduce Δn₁ to the range of 0.52% to 0.53% and adjust R₂/R₁ to approximately 2.6 to 2.7. By these adjustments, we can achieve a suitable equilibrium between the effective area A_eff and the zero dispersion wavelength λ₀.The experimental fiber design achieved a mode field diameter of 9.35 μm and an effective area A_eff of 68 μm2. Additionally, the zero dispersion coefficient exceeding 1.5 ps·nm^-1·km^-1 at 1 460 nm, well-suited for S-band wavelength division multiplexing applications while effectively suppressing four-wave mixing in the S-band. Furthermore, the fiber exhibited a low dispersion slope of only 0.059 ps·nm^-2·km^-1, providing relatively suitable dispersion characteristics in the C and L bands. The fiber also exhibited superior attenuation coefficients of 0.276 dB·km^-1 at 1 383 nm, effectively mitigating the impact of water absorption peaks. The attenuation coefficients at 1 550 nm and 1 625 nm were 0.195 dB·km^-1 and 0.205 dB·km^-1, respectively, facilitating extended transmission distances. Through comparison, it was confirmed that this S+C+L band NZDSF with low dispersion slope and large effective area is well-suited for high-speed, high-capacity, and long-distance optical communication systems.