Optical sinc-shaped Nyquist pulses of exceptional quality

Abstract

Sinc-shaped Nyquist pulses possess a rectangular spectrum, enabling data to be encoded in a minimum spectral bandwidth and satisfying by essence the Nyquist criterion of zero inter-symbol interference (ISI). This property makes them very attractive for communication systems since data transmission rates can be maximized while the bandwidth usage is minimized. However, most of the pulse-shaping methods reported so far have remained rather complex and none has led to ideal sinc pulses. Here a method to produce sinc-shaped Nyquist pulses of very high quality is proposed based on the direct synthesis of a rectangular-shaped and phase-locked frequency comb. The method is highly flexible and can be easily integrated in communication systems, potentially offering a substantial increase in data transmission rates. Further, the high quality and wide tunability of the reported sinc-shaped pulses can also bring benefits to many other fields, such as microwave photonics, light storage and all-optical sampling.

Abstract

The rectangular spectral shape of sinc Nyquist pulses are ideal for data transmission as they make optimal use of the available frequency spectrum. Here Soto et al. develop a scheme for the optical generation of sinc-shaped Nyquist pulses with very high quality, based on the direct synthesis of rectangular, phase-locked frequency combs.