RESUMEN
We develop, analyze and apply a linearization technique based on dual parallel Mach-Zehnder modulator to self-beating microwave photonics systems. The approach enables broadband low-distortion transmission and reception at expense of a moderate electrical power penalty yielding a small optical power penalty (<1 dB).
RESUMEN
We present a model to compute the figures of merit of self-beating Microwave Photonic systems, a novel class of systems that work on a self-homodyne fashion by sharing the same laser source for information bearing and local oscillator tasks. General and simplified expressions are given and, as an example, we have considered their application to the design of a tunable RF MWP BS/UE front end for band selection, based on a Chebyshev Type-II optical filter. The applicability and usefulness of the model are also discussed.
RESUMEN
Multimode interference reflectors (MIRs) were recently introduced as a new type of photonic integrated devices for on-chip, broadband light reflection. In the original proposal, different MIRs were demonstrated based on total internal reflection mirrors made of two deep-etched facets. Although simpler to fabricate, this approach imposes certain limits on the shape of the field pattern at the reflecting facets, which in turn restricts the types of MIRs that can be implemented. In this work, we propose and experimentally demonstrate the use of aluminium-based mirrors for the design of 2-port MIRs with variable reflectivity. These mirrors do not impose any restrictions on the incident field, and thus give more flexibility at the design stage. Devices with different reflectivities in the range between 0 and 0.5 were fabricated in a 3 um thick SOI platform, and characterization of multiple dies was performed to extract statistical data about their performance. Our measurements show that, on average, losses both in the aluminium mirror and in the access waveguides reduce the reflectivities to about 79% of their target value. Moreover, standard deviations lower than ±5% are obtained over a 20 nm wavelength range (1540-1560 nm). We also provide a theoretical model of the aluminium mirror based on the effective index method and Fresnel equations in multilayer thin films, which shows good agreement with FDTD simulations.
RESUMEN
A photonic system capable of estimating the unknown frequency of a CW microwave tone is presented. The core of the system is a complementary optical filter monolithically integrated in InP, consisting of a ring-assisted Mach-Zehnder interferometer with a second-order elliptic response. By simultaneously measuring the different optical powers produced by a double-sideband suppressed-carrier modulation at the outputs of the photonic integrated circuit, an amplitude comparison function that depends on the input tone frequency is obtained. Using this technique, a frequency measurement range of 10 GHz (5-15 GHz) with a root mean square value of frequency error lower than 200 MHz is experimentally demonstrated. Moreover, simulations showing the impact of a residual optical carrier on system performance are also provided.
