In this work, the static and dynamic characteristics of a 1.55 μm optical-fiber transmitter based on wafer-fused VCSEL were studied. The device demonstrated single-mode lasing with SMSR >30 dB over a wide range of currents, and the maximum optical output power at the fiber end more than 2.5 mW. The measured –3 dB modulation bandwidth exceeded 11 GHz, and the maximum bit rate achieved was 25 Gbps. Analysis of the lasing spectra under different amplitude modulations was carried out. Positive chirping (spectra broadening) and fiber chromatic dispersion were limiting factors for the data transmission over SMF-28 fiber.