Long period gratings (LPGs) will play an important role and be widely used in the fields of optical communication and optical fiber sensing. Many useful methods have been proposed to manufacture LPGs. However, there are some obvious disadvantages in these existing methods: high performance but high cost, or easy fabricating but low performance. To overcome these shortcomings, a novel technique is proposed for LPGs fabrication. In this method, a broad spectrum UV source is used instead of UV laser to write LPGs, and more than one LPG can be written simultaneously. As a result, it is easy to write LPGs with high performance, low cost and easy manufacturing. This technique can be used in industrial production of LPGs with very low cost.