We present the performance evaluation of impulse radio ultrawideband (IR-UWB) over fiber using a simple pulse design technique with a high fractional bandwidth. The technique, based on the linear combination of the first-order Gaussian derivatives with different pulse-shaping factors, shows full compliance with Federal Communications Commission mask requirements even in the most severely power-restricted GPS band. We validated our approach with experiments employing an intensity-modulation direct-detection scheme. The experimental setup uses a directly modulated DFB laser at 1302.56 nm and a multimode fiber-coupled photodetector with 24 µm diameter photosensitive area. The transmission link consists of 25 km single-mode fiber or 4.4 km mult...