A Linearized Analog Microwave Photonic link with an Eliminated Even-order Distortions

International audienceAn improved linearized analog microwave photonic link (AMPL) with significant multioctave bandwidth performance is experimentally presented. The proposed AMPL configuration is based on a double dual-parallel Mach-Zehnder modulator and a differential balanced photodetector (BPD). Explicitly, a gallium arsenide (GaAs)-based modulators are used as opposed to the commonly known lithium niobate (LiNbO3) modulators, due to its robustness in the harsh environment. The system configuration is designed to process a carrier suppressed double-sideband signal through the link, and then at the receiver, a carrier suppressed double-sideband signal is combined with an unmodulated optical carrier, which is transmitted through a polarization maintained (PM) optical fiber. In our experiment, only PM-based optical components are used for better system stability. The developed theoretical model of the proposed system illustrates the elimination of even-order distortions and a high suppression to the third-order intermodulation distortions at the BPD. Consequently, the fundamental signal to interference ratio of 60 dB was experimentally achieved. Furthermore, experimental results, simultaneously, demonstrate a significant increase of second-order spurious-free dynamic range and third-order spurious-free dynamic range by 19.5 and 3.1dB, respectively, compared to the previously reported AMPL performances based on polarization multiplexing dual-parallel Mach-Zehnder modulator. To the best of our knowledge, this is the highest dynamic range AMPL system performance deploying GaAs electro-optic modulator which has most significant capabilities in managing RF signals and exhibits excessive performance in harsh operating environment in terms of thermal stability, power-handling, radiation resistance and longevity for aerospace, defense, and satellite-to-ground downlink communication system applications

Research progress of on-chip linearization methods for microwave photonic systems

In this paper, we reviewed and presented our latest progress of linearization methods for microwave photonic systems based on programmable photonic circuits, including the linearization in microwave photonic transmission links and programmable functional circuits.</p

Versatile silicon microwave photonic spectral shaper

Optical modulation plays arguably the utmost important role in microwave photonic (MWP) systems. Precise synthesis of modulated optical spectra dictates virtually all aspects of MWP system quality including loss, noise figure, linearity, and types of functionalities that can be executed. However, for such a critical function, the versatility to generate and transform analog optical modulation is severely lacking, blocking the pathways to truly unique MWP functions including ultra-linear links and low-loss high rejection filters. Here, we demonstrate a versatile radiofrequency (RF) photonic spectral shaper integrated in a silicon photonic circuit. The spectral shaper controls the two modulation bands generated from an electro-optic modulation process in their relative amplitude and phase, offering an enhanced versatility for microwave-photonic modulation applications. Using the spectral shaper, we show electrically tailorable modulation transformations. Furthermore, we show a series of unprecedented RF filtering experiments through monolithic integration of the spectral shaper with a network of reconfigurable ring resonators

Chip-Scale Microwave Photonic Signal Processing

The use of optical technology can provide unprecedented performance to the generation, distribution, and processing of microwave. Recently, on-chip microwave photonics (MWP) has gained significant interests for its numerous advantages, such as robustness, reconfigurability as well as reduction of size, weight, cost, and power consumption. In this chapter, we review our recent progress in ultracompact microwave photonic signal processing using silicon nanophotonic devices. Using the fabricated silicon waveguide, silicon microring resonators (MRRs) and silicon photonic crystal nanocavities, we demonstrate on-chip analog signal transmission, optically controlled tunable MWP filter, and ultra-high peak rejection notch MWP filter. The performance of analog links and the responses of MWP filters are evaluated in the experiment. In addition, microwave signal multiplication and modulation are also demonstrated based on a silicon Mach-Zehnder modulator in the experiment with favorable operation performance. The demonstrated on-chip analog links, MWP filters, microwave signal multiplication/modulation may help understand on-chip analog signaling and expand novel functionalities of MWP signal processing

A photonic chip based frequency discriminator for a high performance microwave photonic link

We report a high performance phase modulation direct detection microwave photonic link employing a photonic chip as a frequency discriminator. The photonic chip consists of five optical ring resonators (ORRs) which are fully programmable using thermo-optical tuning. In this discriminator a drop-port response of an ORR is cascaded with a through response of another ORR to yield a linear phase modulation (PM) to intensity modulation (IM) conversion. The balanced photonic link employing the PM to IM conversion exhibits high second-order and third-order input intercept points of + 46 dBm and + 36 dBm, respectively, which are simultaneously achieved at one bias point.\ud \u

True linearized intensity modulation for photonic analog to digital conversion using an injection-locked mode-locked laser

A true linearized interferometric intensity modulator for pulsed light has been proposed and experimentally presented in this thesis. This has been achieved by introducing a mode-locked laser into one of the arms of a Mach-Zehnder interferometer and injection-locking it to the input light (which is pulsed and periodic). By modulating the injection-locked laser, and combining its output light with the light from the other arm of interferometer in quadrature, one can achieve true linearized intensity modulator. This linearity comes from the arcsine phase response of the injection-locked mode-locked laser (as suggested by steady-state solution of Adler\u27s equation) when it is being modulated. Mode-locked lasers are fabricated using a novel AlGaInAs-InP material system. By using the BCB for planarization and minimizing the metal pad size and directly modulating the laser, we have achieved very effective fundamental hybrid mode-locking at the repetition rate of ~ 23 GHz. This laser also provided the short pulses of 860 fs and 280 fs timing jitter integrated from 1 Hz- 100 MHz. The linearized intensity modulator has been built by using two identical two-section mode-locked lasers with the same length, one as the slave laser in one of the arms of the Mach-Zehnder interferometer injection-locked to the other one as the master which is the input light to the modulator. A low V? of 8.5 mV is achieved from this modulator. Also the current of the gain section or the voltage of the saturable absorber section of the slave laser has been used to apply the modulation signal. A spur free dynamic range of 70 dB.Hz2/3 is achieved when modulating the modulator through the saturable absorber. Modulating the saturable absorber provides a reduced third-order intermodulation tone with respect to modulating the gain. This is simply because of the unwanted amplitude modulation created when modulating the gain section current. Finally an improved design is proposed and demonstrated to improve the modulator performance. This is achieved by introducing a third section to the laser. Using the impurity free vacancy disordering technique the photoluminescence peak of this section is blue-shifted selectively and therefore there would not be any absorption in that passive section. By applying the modulation signal to this passive section rather than applying it to the gain section or saturable absorber section, the amplitude and phase modulation could be decoupled. The experimental results have presented here and an almost six-fold reduction in V? and 5 dB improvement in spur free dynamic range have been achieved. The proposed and demonstrated configuration as an analog optical link has the potential to increase the performance and resolution of photonic analog-to-digital converters

Noise and distortion analysis of dual frequency comb photonic RF channelizers

Dual frequency combs are emerging as highly effective channelizers for radio frequency (RF) signal processing, showing versatile capabilities in various applications including Fourier signal mapping, analog-to-digital conversion and sub-sampling of sparse wideband signals. Although previous research has considered the impact of comb power and harmonic distortions in individual systems, a rigorous and comprehensive performance analysis is lacking, particularly regarding the impact of phase noise. This is especially important considering that phase noise power increases quadratically with comb line number. In this paper, we develop a theoretical model of a dual frequency comb channelizer and evaluate the signal to noise ratio limits and design challenges when deploying such systems in a high bandwidth signal processing context. We show that the performance of these dual comb based signal processors is limited by the relative phase noise between the two optical frequency combs, which to our knowledge has not been considered in previous literature. Our simulations verify the theoretical model and examine the stochastic noise contributions and harmonic distortion, followed by a broader discussion of the performance limits of dual frequency comb channelizers, which demonstrate the importance of minimizing the relative phase noise between the two frequency combs to achieve high signal-to-noise ratio signal processing

Architectures and Novel Functionalities for Optical Access OFDM Networks "Arquitecturas y Nuevas Funcionalidades para Redes OFDM de Acceso Óptico"

En los últimos años ha habido un gran aumento en el despliegue de redes de acceso ópticas de fibra hasta el hogar (FTTH, del inglés fibre-to-the home). FTTH es una solución flexible, una tecnología de acceso de futuro que permite proporcionar tasas de datos del orden de Gbit/s por ususario. Diversos estudios indican que FTTH se convertirá en la diferencia clave entre los operadores más importantes. Además, FTTH es la única tecnolotgía capaz de crear nuevas fuentes de ingresos de aplicaciones de alta velocidad, como por ejemple entretenimiento de alta definición (vído y juegos de alta definición...) Dede el punto de vista del operador, una de las vientajas importantes que proporciona FTTH es que permite una mayor eficiencia operativa en coparción con otras tecnologías de acceso, principalmente por la reducción de costes de mantenimiento y de operación. Además, FTTH reduce los requisitos de los equipos de las centrales. Esta tesis doctoral tiene como ojetivo extender estas ventajas más allá del concepto FTTH mediante la integración de la red óptica de distribución desplegada dentro del hogar así como el enlace radio final de corto o medio alcance inalámbrico. Esto proporciona una arquitctura de red FFTH integrada de extremo a extremo. De este modo, los beneficios de la reducción de costes operativos y mayor eficiencia se extienden hasta el usuario final de la red. En esta tesis doctoral, se propone una arqutectura de acceso integrada óptica-radio basada en la multiplexación por división ortogonal de fecuencia (OFDM, del inglés orthogonal frequency división multiplexing) para proporcionar diferentes servicios al usuario como Internet, teléfono/voz, televisión de lata definición, conexión inalámbrica y seguridad en el hogar. Las señales OFDM se utilizan en muchos estándares inalámbricos como las señales de banda ultraancha (UWB, del inglés ultra-wide band), WiMAX, LTE, WLAN, DVB-T o DAB. Estos formatos aprovechan las características intrínsecas de la modulación OFDM como su mayor inmunidad ante desvanecimiento multi-camino. Esta tesis incluye la propuesta y la demostración experimental de la transmisión simultánea y bi-direccional de señales OFDM multi-estándar en radio-sobre-fibra proporcionando servicios triple-play basados en OFDM como UWB para televisión de alta definición, WiMAX para datos de Internet, y LTE para el servicio telefónico.Morant Perez, M. (2012). Architectures and Novel Functionalities for Optical Access OFDM Networks "Arquitecturas y Nuevas Funcionalidades para Redes OFDM de Acceso Óptico" [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/15076Palanci