This paper presents a novel ring-shaped photonic crystal fiber (PCF)-based optical device, incorporating mathematical modeling and innovative design, for the early detection of malaria in human blood. The sensor utilizes a gold-coated PCF structure to achieve ultra-high amplitude sensitivity for different infected malaria RBC phases in human blood. The Schizont, Trophozoite, and Ring phases exhibited resonance wavelength shifts at 650 nm, 670 nm, and 690 nm, respectively, with maximum amplitude sensitivities reaching up to 8.3 × 105 RIU−1. The device demonstrated excellent linearity (R 2 ∼ 0.99) and high wavelength sensitivities of up to 2857.14 nm/RIU. The proposed design offers unprecedented amplitude sensitivity not reported so far, establishing it as a highly promising, non-invasive, and cost-effective tool for rapid malaria diagnosis in medical applications.