In a photoconductive semiconductor switch (PCSS) ultrawideband (UWB) array system, optical fiber bundles with several hundreds or more fibers are employed to distribute laser beam energy and yield multiple laser beams with the same energy and coherence. Ideally, if each fiber of the bundle is the same length, the laser beams transmit in the fiber and may arrive to the PCSS simultaneously in the UWB array system. In this work, the coupling rate of the fiber bundle is estimated. The experimental result of dividing laser energy shows that multiple lasers can be obtained by using a fiber bundle. Specifically, the experiments on the 17-PCSS antenna array radiation indicate that the pulses generated by PCSS give up only several picoseconds of time jitters, thus demonstrating that laser distribution by fiber bundle can be used for UWB coherent combination.