<div style="text-align:justify;"> A photonics approach to generate a linearly chirped waveform with increased TBWP is proposed and investigated. The time bandwidth product (TBWP) of the linearly chirpe...<div style="text-align:justify;"> A photonics approach to generate a linearly chirped waveform with increased TBWP is proposed and investigated. The time bandwidth product (TBWP) of the linearly chirped waveform is improved based on optical microwave frequency multiplying combined with temporal synthesis. An integrated dual-polarization modulator and an optical filter are utilized to perform frequency doubling operation by generating an orthogonally polarized optical signal, which consists of an optical carrier in one polarization direction and a second-order chirped optical sideband in another. Then the orthogonally polarized optical signal puts into a polarization modulator (PolM) to perform phase coding process. By driving a Pseudorandom (PN) sequence to the PolM, the time duration of the generated bandwidth doubled linearly chirped waveform can be synthesized to arbitrary length. The approach is verified by simulation. A linearly chirped waveform with central frequency of 8.25 GHz, bandwidth of 500 MHz, time duration of 6.4 ns is used to generate a synthesized waveform with central frequency of 16.5 GHz, bandwidth of 1 GHz, time duration of 819.2 ns. The TBWP of the linearly chirped signal is improved from 3.2 to 819.2. The proposed method features arbitrary large TBWP, and it can be used in a radar system to improve its resolution. </div>展开更多
A switchable down-,up-and dual-chirped microwave waveform generation technique with improved time–bandwidth product(TBWP)is proposed and demonstrated based on a dual-polarization dual-parallel Mach–Zehnder modulator...A switchable down-,up-and dual-chirped microwave waveform generation technique with improved time–bandwidth product(TBWP)is proposed and demonstrated based on a dual-polarization dual-parallel Mach–Zehnder modulator(DPDPMZM)cascaded with a polarization modulator(Pol M).By properly controlling the phase shifts of the radio frequency signals applied to the DP-DPMZM,switchable down-,up-and dual-chirped waveforms with simultaneous frequency and bandwidth doubling can be generated.To enlarge the TBWP further,splitting parabolic signal and phase-encoding splitting parabolic signal are used to drive the Pol M for the enhancement of bandwidth and time duration.Numerical results demonstrate the generation of down-,up-and dual-chirped microwave waveform with TBWP of 8,160 and 10240.The proposed method may find applications in future multifunction radar systems due to the high performance and flexibility.展开更多
Linearly chirped microwave waveforms(LCMWs)are indispensable in advanced radar systems.Our study introduces and validates,through extensive experimentation,the innovative application of a thin-film lithium niobate(TFL...Linearly chirped microwave waveforms(LCMWs)are indispensable in advanced radar systems.Our study introduces and validates,through extensive experimentation,the innovative application of a thin-film lithium niobate(TFLN)photonic integrated circuit(PIC)to realize a Fourier domain mode-locked optoelectronic oscillator(FDML OEO)for generating high-precision LCMW signals.This integrated chip combines a phase modulator(PM)and an electrically tuned notch micro-ring resonator(MRR),which functions as a rapidly tunable bandpass filter,facilitating the essential phase-to-intensity modulation(PM-IM)conversion for OEO oscillation.By synchronizing the modulation period of the applied driving voltage to the MRR with the OEO loop delay,we achieve Fourier domain mode-locking,producing LCMW signals with an impressive tunable center frequency range of18.55 GHz to 23.59 GHz,an adjustable sweep bandwidth from 3.85 GHz to 8.5 GHz,and a remarkable chirp rate up to 3.22 GHz/μs.Unlike conventional PM-IM based FDML OEOs,our device obviates the need for expensive tunable lasers or microwave sources,positioning it as a practical solution for generating high-frequency LCMW signals with extended sweep bandwidth and high chirp rates,all within a compact and cost-efficient form factor.展开更多
文摘<div style="text-align:justify;"> A photonics approach to generate a linearly chirped waveform with increased TBWP is proposed and investigated. The time bandwidth product (TBWP) of the linearly chirped waveform is improved based on optical microwave frequency multiplying combined with temporal synthesis. An integrated dual-polarization modulator and an optical filter are utilized to perform frequency doubling operation by generating an orthogonally polarized optical signal, which consists of an optical carrier in one polarization direction and a second-order chirped optical sideband in another. Then the orthogonally polarized optical signal puts into a polarization modulator (PolM) to perform phase coding process. By driving a Pseudorandom (PN) sequence to the PolM, the time duration of the generated bandwidth doubled linearly chirped waveform can be synthesized to arbitrary length. The approach is verified by simulation. A linearly chirped waveform with central frequency of 8.25 GHz, bandwidth of 500 MHz, time duration of 6.4 ns is used to generate a synthesized waveform with central frequency of 16.5 GHz, bandwidth of 1 GHz, time duration of 819.2 ns. The TBWP of the linearly chirped signal is improved from 3.2 to 819.2. The proposed method features arbitrary large TBWP, and it can be used in a radar system to improve its resolution. </div>
基金the National Natural Science Foundation of China(Grant Nos.U2006217,61775015,and 62101027)the Fundamental Research Funds for the Central Universities(Grant Nos.2021JBZ103 and 2021YJS002)。
文摘A switchable down-,up-and dual-chirped microwave waveform generation technique with improved time–bandwidth product(TBWP)is proposed and demonstrated based on a dual-polarization dual-parallel Mach–Zehnder modulator(DPDPMZM)cascaded with a polarization modulator(Pol M).By properly controlling the phase shifts of the radio frequency signals applied to the DP-DPMZM,switchable down-,up-and dual-chirped waveforms with simultaneous frequency and bandwidth doubling can be generated.To enlarge the TBWP further,splitting parabolic signal and phase-encoding splitting parabolic signal are used to drive the Pol M for the enhancement of bandwidth and time duration.Numerical results demonstrate the generation of down-,up-and dual-chirped microwave waveform with TBWP of 8,160 and 10240.The proposed method may find applications in future multifunction radar systems due to the high performance and flexibility.
基金Natural Science Foundation of Hebei Province(F2024201002)Interdisciplinary Research Program of Natural Science of Hebei University(DXK202204)Research Start-up Foundation of High-Level Talents Introduction(8012605)。
文摘Linearly chirped microwave waveforms(LCMWs)are indispensable in advanced radar systems.Our study introduces and validates,through extensive experimentation,the innovative application of a thin-film lithium niobate(TFLN)photonic integrated circuit(PIC)to realize a Fourier domain mode-locked optoelectronic oscillator(FDML OEO)for generating high-precision LCMW signals.This integrated chip combines a phase modulator(PM)and an electrically tuned notch micro-ring resonator(MRR),which functions as a rapidly tunable bandpass filter,facilitating the essential phase-to-intensity modulation(PM-IM)conversion for OEO oscillation.By synchronizing the modulation period of the applied driving voltage to the MRR with the OEO loop delay,we achieve Fourier domain mode-locking,producing LCMW signals with an impressive tunable center frequency range of18.55 GHz to 23.59 GHz,an adjustable sweep bandwidth from 3.85 GHz to 8.5 GHz,and a remarkable chirp rate up to 3.22 GHz/μs.Unlike conventional PM-IM based FDML OEOs,our device obviates the need for expensive tunable lasers or microwave sources,positioning it as a practical solution for generating high-frequency LCMW signals with extended sweep bandwidth and high chirp rates,all within a compact and cost-efficient form factor.
