A dual parallel Mach–Zehnder modulator linearization scheme based on 90° phase shifters

In this paper, a dual-drive dual-parallel Mach–Zehnder Modulator based linearization scheme is implemented by utilizing only two phase shifters and comprehensively demonstrated for a photonic transmission link. Third order intermodulation distortion is suppressed by adjusting angles of electrical phase shifters i.e. π/2 and−π/2 and a non-linear distortion immune system can be proposed for microwave photonic link. A complete suppression in intermodulation terms and 20.8 dB enhancements are found in spurious free dynamic range (SFDR). SFDR reaches 135.6 dB Hz4/5 by suppressing major spurious contributors of third order intermodulation distortions in optical domain only which ensures the improvement in performance of link against non-linear terms.

INTERMODULATION DISTORTIONS IN TUNABLE LC FILTERS BASED ON VARICAPS

The article discusses the issues of minimizing intermodulation distortions arising in tunable bandpass filters made with the use of varicaps. It presents the analysis of the tunable filter circuits, on the basis of which we determined the circuits with minimum intermodulation distortions.

Overlapped Gate-Source/Drain H-shaped TFET: Proposal, Design and Linearity Analysis

In this paper, the proposed design of H-shaped TFET has been discussed. This design is providing a high Ion/Ioff ratio with better Ion. HfO2 is used for better tunneling current. With this device, Different parameters such as unit parameter, analogue parameter, and linearity parameter have been studied and investigated the output of the H-TFET. As unit parameters, the electric field, electric potential, energy band diagram, and non-local band-to-band tunneling rate (BTBT) have all been observed. Second and third-order harmonics distortion (HD2, HD3), third-order current intercept point (IIP3), third-order intermodulation distortions (IMD3), and second and third-order voltage intercept point (VIP2, VIP3) are evaluated as linearity parameters that characterize the device's distortions and linearity. We obtained Ion\({\text{=1.6×}10}^{-4}\) A/µm, Ioff=2.1\({\text{×}10}^{-19}\) A/µm, Ion /Ioff=7.6\({\text{×}10}^{14}\),threshold voltage Vt=0.3449 V. © 2017 Elsevier Inc. All rights reserved.

Influence of Fiber Properties on Harmonic and Intermodulation Distortions of Semiconductor Lasers

This paper introduces modeling and simulation of the harmonic and intermodulation distortions of semiconductor laser radiating an optical fiber link. The study is based on the rate equation model of semiconductor lasers excited by injection current with two sinusoidal tones separated by a radio frequency. The modulated laser signal is modeled in both the time and frequency domains. The laser signal distortions include the 2nd and 3rd harmonic distortion (2HD and 3HD), and the third-order intermodulation distortion IMD3. The laser is assumed to be modulated around its relaxation frequency. Influence of the modulation depth on the signal distortion is investigated when the laser is free running and when it is radiating a fiber link. In the latter case, influences of the attenuation and chromatic dispersion on the signal dispersion are elucidated when the fiber length increases up to 10 km. The results show that the fiber attenuation does not affect the signal distortion, whereas the chromatic dispersion affects both the harmonic distortions and intermodulation distortion. Sending the laser signal down an optical fiber of length ~ 5km can help in minimizing 2HD which is the dominant harmonic distortion of the modulated signal. This range of optical fiber is also characterized with intermodulation distortion less than 0dBc.

Microwave Photonics Analog Link based on two Integrated D-DPMZM Linearized Signals and with Eliminated odd Harmonics and all IMD’s.

A novel Microwave Photonic Link (MPL) system configuration based on two Dual-drive Dual-parallel Mach-Zehnder modulators (D-DPMZMs) and two Balanced Photo-Detectors (BPDs) is reported. The Intermodulation Distortions (IMDs), as well as the harmonic distortions have been eliminated. The proposed linearization of RF signal configuration is double side banded in both D-DPMZM. A full mathematical model has been developed and simulations have been implemented for the proposed configuration. The RF linearization for this configuration has been tested by introducing an additional RF signal, as well as phase and intensity errors in MZ branches. The proposed MPL system configuration exhibits significant performance and it will have great impact on aerospace, radar, and satellite-to-ground downlink communication system applications.