Power-efficient FCC-compliant UWB generator using polarization-maintaining FBG-based spectral shaper and incoherent wavelength-to-time mapping

摘要

A novel scheme to generate power-efficient FCC-compliant UWB has been proposed using polarization-maintaining FBG-based spectral shaper and incoherent wavelength-to-time mapping. The target UWB pulse is designed based on the linear combination of four Gaussian pulses with the same pulsewidth, which can be considered as a Gaussian pulse that is bandpass-filtered by a four-tap nonuniformly-spaced filter. FCC-compliant UWB with high spectral power efficiency (46.2-57.2%) can be realized using optimized parameters. Temporal gate and spectral shaper are two key components of an incoherent spectral shaping and wavelength-to-time mapping (SS-WTTM) system. Owing to strong nonlinear absorption characteristic of electro-absorption modulator (EAM), lowpass-filtered electrical pulse is compressed for the implementation of narrow optical gate. 45-ps optical gate is achieved experimentally using 10-Gb/s EAM driven by 10-Gb/s bit pattern generator. This cost-effective gate can be extended to general incoherent SS-WTTM method to substitute commonly-used high-speed gate. Furthermore, a simple spectral shaper is designed based on a uniform polarization-maintaining FBG. To the best of our knowledge, it is the first time to achieve power-efficient FCC-compliant UWB using all-fiber spectral shaper, which has the advantages of small size, low insertion loss, and feasibility of integration. Proposed UWB generator is demonstrated by both simulation and experiment. FCC-compliant UWB with 10-dB bandwidth of 6.25-GHz, and spectral power efficiency of 55.9% is realized successfully.