Study On The Channel Mismatches In Time-Interleaved Photonic Analog-to-Digital Conversion

The work of this dissertation focuses on the channel mismatch characteristics of the time-interleaved photonic analog-to-digital conversion(TIPADC)system.Firstly,based on theoretical model of TIPADC system,deriving the equivalent response of the N-channel TIPADC system.It is found that the architecture of its system equivalent response under specific conditions is equivalent to the typical time-interleaved electrical analog-to-digital conversion(TIEADC)system.Based on the relevant theory and typical methods of channel mismatch correction in TIEADC system,the influence of channel mismatch correction on TIPADC system is studied.Secondly,the study found that the channel characteristics exhibited by the TIPADC system are related to photodetection.It is necessary to study the influence of the back-end probe response on the channel mismatch.Based on the channel response of TIPADC system,the relationship between photodetection response and channel mismatches,and its effects on correction of mismatches are analyzed.The simulation based on a two-channel TIPADC system is performed.The results show that the influence of channel mismatches is irrelevant to the frequency when there is not photondetection response induced crosstalk,and hence mismatch parameters obtained at a single frequency can be used to correct the mismatches.In the case of photondetection response causing crosstalk,the channel response under different gains has the same proportion change while the channel response at different time mismatches changes in different proportions,and mismatch parameters obtained at a single frequency can only correct the gain mismatches.Thirdly,in order to verify the influence of the photondetection response on system channel mismatch estimation and correction,calibration-based channel mismatch estimation methods are employed,that is,the single-frequency signal is used to calibrate the gain mismatch and time mismatch parameters of the corresponding frequency points.For the sampled data of other sampled signals,the typical correction method of TIEADC system is used for calibration.The simulation results are consistent with the theoretical analysis.The gain mismatch ratio,channel mismatch ratio,backend detection bandwidth,and system channel number were further adjusted,the simulation results are consistent with the foregoing conclusions.Finally,an experimental platform for the TIPADC system was built based on time division multiplexing(OTDM)and 16-channel wavelength division multiplexing(WDM).The total sampling rate of the system is 128GS/s.We test the performance of system,by adding a low-noise amplifier,system performance is optimized under the same conditions.