Generation of optical pulse trains by repetition rate multiplications with cascaded long-period fiber gratings

Cascaded long-period fiber gratings are used to achieve multiplications of the repetition rate of pulse trains. The generated pulse trains have 2/spl times/, 4/spl times/, and 8/spl times/ multiplications, and the maximum achieved repetition rate is 416.7 GHz.

1. Introduction

The generation of optical pulse trains with a repetition rate higher than hundreds of GHz is of great interest to applications such as large-capacity optical-time-division-multiplexed (OTDM) systems. Recently, the temporal fractional Talbot effect in optical fibers was used to get a repetition-rate multiplication; where the dispersion property of an optical fiber was used [1], [2]. The use of chirped superimposed fiber Bragg gratings as the dispersive element has been proposed [3]. An integrated optical multiplexer based on a hybrid planar light-wave circuit also realized stable and high-speed OTDM signal generations [4]. In this work, we propose a novel technique for ultrashort pulse multiplication based on long-period fiber gratings (LPGs). We demonstrate the multiplicators that give and multiplications with the maximum repetition rate of 416.7 GHz (repetition period of 2.4 ps). The experimentally measured performance of the proposed system is discussed and compared with the simulated results.