In this work, we report the development of an external-cavity wavelength-swept amplified spontaneous emission (ASE) source with high output power and high tuning speed based on an efficient electro-optic effect of beam deflection. The wavelength-swept ASE source is capable of delivering stable output power with averaged intensity of 100 mW in a wide spectrum tuning range of over 80 nm around the wavelength of 1550 nm. The light source will have important applications in optical communications, biomedical imaging, spectral analysis and sensing.