Combined Application of Broadband and Ultra-Narrowband Discrete Frequency Packets Fundamentals for Creating Compact Microwave Photonic Analyzers of Broadband Amplitude Mach-Zehnder Modulators and Photodetectors Spectral Characteristics. Part IV. Microwave Photonic Analyzer of Spectral Characteristics for Wideband Amplitude Mach-Zehnder Modulators Based on Dual-Band Four-Frequency Probing Radiation Obtained by Frequency Multiplication of Splitted Scanning Frequency

The objective of this work, consisting of four parts, is to solve the problems of combined application of the principles of wideband (WBDFP) and ultra-narrowband (UNBDFP) discrete frequency packages for improving the metrological characteristics, minimizing the structure and reducing the cost of microwave photonic spectral characteristic analyzers (MPSCA) for wideband electro-optic modulators and photodetectors, implemented on the import-substituting element base. The first part considers the issues of forming a dual-band dual-frequencies probing radiation (DDPR) with a suppressed carrier and equal component amplitudes, which form the basis of a WBDFP, and evaluates its functional and system characteristics necessary to achieve the purpose of the work. The second part of the work presents the principles of analyzing a DDPR converted into a wideband photodetector, based on a simple in structure microwave photonic interrogator, which differs significantly in the operating principle from an EVA and allows to reduce the cost of a MPSCA as a whole due to the exclusion of the latter. The principles of constructing the MPSCA for the wideband photodetector with a sixfold increase in the measurement range of the frequency response and obtaining data for its construction at the output of the tested photodetector from two narrow-band filters at single and tripled splitting frequencies are shown in the third part of the work using the example of the symmetrical dual-band two-frequency probing radiation, as a variant of the dual-band multifrequency probing radiation (DMFPR), synthesized based on the multiplication of the split scanning frequency and the principles of the radio-photonic interrogation with the OFNLC. The present, fourth part of the work, using the example of the symmetrical dual-band four-frequency probing radiation, as a variant of the DMFPR, synthesized based on the multiplication of the split scanning frequency and the principles of the microwave photonic interrogation with the OFNLC, shows the principles of constructing the MPSCA of the WBAMMZ with a threefold increase in the measurement range of the frequency response and obtaining data for its construction at the output of the calibrated WBPD from two narrow-band filters at single and tripled splitting frequencies. The latter is selected in accordance with the requirements of the UNBDFP theory from the conditions taking into account the width of the laser radiation line and the noise characteristic of the photodetector, the resolution of the measurements and the width of the radio-frequency component of the beat signal.

broadband Mach-Zehnder amplitude modulator, split scanning frequency, microwave photonic spectrum analyzer, frequency multiplication, broadband discrete frequency package, ultra-narrowband discrete frequency package, microwave photonics, microwave photonic interrogator