Xiaofeng Peng

Wideband tunable optoelectronic oscillator based on the deamplification of stimulated Brillouin scattering

A wideband tunable optoelectronic oscillator (OEO) based on the deamplification of stimulated Brillouin scattering (SBS) is proposed and experimentally demonstrated. A tunable single passband microwave photonic filter (MPF) utilizing phase modulation and SBS deamplification is used to realize the tunability of the OEO. Theoretical analysis of the MPF and phase noise performance of the OEO are presented. The frequency response of the MPF is determined by the + 1st sideband attenuation due to SBS deamplification and phase shift difference between the two sidebands due to chromatic dispersion and SBS. The close-in (< 1 MHz) phase noise of the proposed OEO is shown to be dominated by the laser frequency noise via phase shift of SBS. The conversion of the laser frequency noise to the close-in phase noise of the proposed OEO is effectively reduced compared with the OEO based on amplification by SBS. Tunable 7 to 40 GHz signals are experimentally obtained. The single-sideband (SSB) phase noise at 10 kHz offset is -128 dBc/Hz for 10.30 GHz signal. Compared with the OEO based on SBS amplification, the proposed OEO can achieve a phase noise performance improvement beyond 20 dB at 10 kHz offset. The maximum frequency and power drifts at 10.69 GHz are within 1 ppm and 1.4 dB during 1000 seconds, respectively. To achieve better close-in phase noise performance, lower frequency noise laser and higher pump power are preferred. The experimental results agree well with the theoretical models.

Sensitivity improvement of phase noise measurement system using photonic-delay based frequency discriminator

By suppressing the additive phase noise induced by light scattering in the optical fiber and optical interference due to the optical reflection in a microwave phase noise measurement system using photonic-delay based frequency discriminator, the sensitivity improvement of 10 dB is experimentally achieved. Using the proposed measurement scheme, a single sideband phase noise is measured to be −145 dBc/Hz at 10 kHz offset for a 10-GHz OEO.

Photonic sub-sampling of signal at 43.1-GHz using optical comb based on an optoelectronic oscillator

A 10 GS/s photonic sub-sampling ADC is proposed and experimentally demonstrated. The single-sideband phase noise of the optoelectronic oscillator is tested to be −128 dBc/Hz at 10 kHz offset and the aperture jitter of the photonic ADC is 40.3 fs with the integral interval from 1 kHz to 10 MHz. 23 GHz and 43.1 GHz signals are sampled by the system with the ENOB of 5.0 bits and 4.2 bits.

10 GHz low timing-jitter and broadband optical comb generation based on an optoelectronic oscillator

10 GHz repetition rate, low timing-jitter and broadband optical comb generation based on a low phase noise optoelectronic oscillator is experimentally demonstrated. 10 GHz repetition rate optical comb and 10 GHz RF signal are obtained, simultaneously. A timing-jitter of 52.8 fs (integral range from 100 Hz to 1 MHz) for the optical comb and a phase noise of −132 dBc/Hz at 10 kHz offset for the RF signal are experimentally achieved. The influence of laser frequency noise on the timing-jitter of the optical comb is also investigated.