Experimental photonic generation of chirped pulses using nonlinear dispersion-based incoherent processing

Abstract

We experimentally demonstrate, for the first time, a chirped microwave pulses generator based on the processing of an incoherent optical signal by means of a nonlinear dispersive element. Different capabilities have been demonstrated such as the control of the timebandwidth product and the frequency tuning increasing the flexibility of the generated waveform compared to coherent techniques. Moreover, the use of differential detection improves considerably the limitation over the signalto-noise ratio related to incoherent processing.

Incoherent Photonic Processing for Chirped Microwave Pulse Generation

“…For our case, the signals obtained experimentally have been softened from square form of the optical source power spectral density due to hmod(t). (b) In contrast to our previous work [13], the control of the chirp sign for being both positive and negative is achieved by means of the proper adjustment of the optical source. (c) The use of incoherent optical sources and dispersive elements permits to aim a full and independent reconfigurability of the central frequency, time-bandwidth product, envelope and chirp sign in comparison to fixed coherent techniques [9][10][11].…”

“…4 and 5 some slight differences can be observed in terms of temporal duration and instantaneous frequency range. Our previous work [12,13] suggests that the optical signal could be affected by the nonlinear effects of the fiber link. Nevertheless, the consideration of this fact is far from the purpose of the approach presented in this paper which is focused in the chirp reconfigurability.…”

“…Recently, we theoretically analyzed [12] and experimentally demonstrated [13] the generation of chirped pulses based on the processing of incoherent optical signals by means of non-linear dispersive elements. The use of incoherent sources permits to increase the reconfigurability of the generated pulses in comparison to coherent techniques.…”

“…The use of incoherent sources permits to increase the reconfigurability of the generated pulses in comparison to coherent techniques. In fact, waveform reconfigurability in terms of envelope, central frequency and chirp magnitude was experimentally proved [13]. However, chirp sign is fixed by the dispersion parameters of the non-linear dispersive element limiting the control for a fixed magnitude value.…”