International audienceElectro-optic modulators are key components in high bit-rate optical transmissions. Decreasing the manufacturing cost without damage on performances is one of the most challenging issues for such components. We demonstrate that the electro-optic modulators based on polymer are compatible with high bandwidth requirements. Indeed, according to the results obtained by numerical simulation and partly validated by experiments, with the via-free GCPW-MS-GCPW electrodes proposed and analyzed in this article, the (400 MHz–67 GHz) bandwidth is achievable with electro-optic modulators based on suitable polymers. These encouraging results are very useful for low-cost mass production of polymer-based electro-optic modulators for a wide range of applications: digital and analogue high bit-rate transmissions

Analog-to-digital converters (ADC) are an important part of realizing direct digital receivers in future communication systems, where broad bandwidth, high effective number of bits, and low DC power consumption are an important requirement of achieving it at microwave frequencies.Due to a number of physical limitations of electrical ADC, design of an all-optical analog-todigital converter (AOADC) is pursued and presented here based on highly stable mode-locked laser based clock signal pulses for optical sampling, and a combination of leaky waveguide optical deflector using electro-optical (EO) polymers and stationary optical windows followed with high-speed photodetectors as optical quantizer. The reported principle of the AOADC is to convert a broadband RF signal into a spatially sampled light using optical deflection angle variation before quantizing it using either binary or Gray coded optical windows. The design and modeling of an AOADC working up to 20 GHz RF frequencies (with Nyquist sampling rate of over 40 GS/s) and for providing a resolution of better than 6 bits with under 4W of power consumption. Performance is currently limited by both optical and microwave attenuation in the available EO polymers.

International audienceAn ultra-wideband complex permittivity extraction method is reported here using numerical fitting of scattering parameters to measured results. A grounded coplanar waveguide transmission line is realized on an unknown dielectric material, whose dielectric constant and loss tangent are extracted by the best fitting of the simulated magnitude, |S21|, and phase, ϕ21, of forward scattering parameter using an electromagnetic full-wave simulator (high frequency structure simulator) to the measured results. The genetic algorithm is employed for optimum rapid extraction, where errors between the numerically simulated and measured S21 (|S21| and ϕ21) are minimized in an iterative manner. As long as the convergence criterion is not satisfied, modifications to dielectric properties are made with this genetic algorithm implemented in Matlab. Feasibility of this extraction technique is validated on benzocyclobutane polymer from 10 MHz to 40 GHz