We experimentally demonstrate a linearized Y-fed directional coupler (DC) modulator based on an electro-optic (EO) polymer waveguide. The spurious free dynamic range of 119 dB/Hz2/3, which is 11 dB higher than that of the conventional Mach-Zehnder modulator, is achieved by introducing the reversed Δβ technique in the two-section Y-fed DC. The in-device EO coefficient (r33) of the fabricated device is as high as 79 pm/V in 1.55 μm wavelength, which is 88% of a single film r33 of LPD-80/APC.