Swept-source optical coherence tomography (SS-OCT) is a non-invasive imaging method using a frequency-swept laser to produce detailed cross-sectional images. It offers enhanced imaging speed, improved sensitivity, and a wider scanning range but faces an imaging ambiguity known as the complex conjugate artifact (CCA). To overcome CCA, 3×3 coupler systems are used but require trigonometric conversions. This study presents an SS-OCT system with a 4×4 coupler and dual reference arms, enabling direct quadrature detection and balanced photodetection, thereby doubling the imaging depth and sensitivity. Additionally, the dual reference arms that modulate the optical path difference extend the depth range twofold. Combining both the 4×4 coupler and dual reference arms, the proposed system achieves a fourfold increase in the depth range compared to conventional SS-OCT systems.