Showing papers by "Richard DeSalvo published in 2011"

Photonic frequency conversion for wideband RF-to-IF down-conversion and digitization

Abstract: A photonic frequency converter based on optical sideband filtering can be used to produce up- and down-converted signals over a wide range of RF frequencies. The reduction of mixing spurs provides an important advantage over conventional RF mixers for wide-band operation. We demonstrate down-conversion from 5 – 20 GHz to a 100 MHz IF with positive gain and high linearity, and direct digitization of down-converted RF signals at 10 and 20 GHz with low degradation of ADC performance.

Scalable Photonic-Assisted Wideband Frequency Converter

Abstract: We present a photonic-assisted wideband tunable RF frequency converter with low phase noise to provide RF to IF frequency translation, and demonstrate 121 dB*Hz2/3 spur-free dynamic range at 20 GHz RF and 2 GHz IF.

Photonic-based low phase noise frequency synthesis for RF-to-millimeter wave carriers and wideband RF-to-IF down-conversion

Abstract: We present a photonic method for tunable high frequency carrier generation and wideband tunable RF frequency down-conversion with low phase noise. The phase noise of the photonic generated RF/IF signal is limited by the RF signal generator used to synthesize the optical local oscillators. We show phase noise measurements of photonic frequency synthesized carriers at 24 GHz and down-conversion measurements with +24 dBm OIP3 and positive gain from 5 – 20 GHz RF and 100 MHz IF, with ADC-limited digitization.

Tunable RF filter device using optical waveguides with dispersion slopes of opposite signs and related methods

Abstract: A tunable Radio Frequency (RF) filter device includes a tunable optical source configured to generate an optical carrier signal, and a modulator coupled to the tunable optical source and configured to modulate the optical carrier signal with an RF input signal. The tunable RF filter device may also include first and second optical waveguides coupled to the modulator and having first and second dispersion slopes of opposite sign, and an optical-to-electrical converter coupled to the first and second optical waveguides and configured to generate an RF output signal with a frequency notch therein based upon the tunable optical source.

Dynamic linearity improvement of phase and frequency modulated microwave photonic links using optical lattice filter discriminators

Abstract: A phase modulated (PM) microwave photonic link (MPL) with linearity improvement is presented. The link demodulates the PM using a phase discriminator based on a dynamically tunable, integrated, sixth-order optical lattice filter in planar lightwave circuit (PLC) technology. The linearity of the demodulation process is optimized by using electrical spectrum monitoring and a feedback algorithm to automatically choose the filter coefficients. For a 2 GHz modulation frequency, the link achieves a 6.7 dB improvement in the third-order output intercept point (OIP3) for intermodulation distortion (IMD) over a Mach-Zehnder interferometer (MZI).

Tunable RF filter device using optical waveguide paths with splitter and combiner pairs and related methods

Abstract: A tunable Radio Frequency (RF) filter device includes a tunable optical source generating an optical carrier signal, and a modulator coupled to the tunable optical source and modulating the optical carrier signal with an RF input signal The tunable RF filter device may include first and second optical waveguide paths coupled to the modulator and having first and second dispersion slopes of opposite sign from each other, one or more of the first and second optical waveguide paths comprising an optical splitter and combiner pair therein, and an optical-to-electrical converter coupled to the first and second optical waveguide paths and generating an RF output signal with a frequency notch therein based upon the tunable optical source

Eliminating co-location radio interference with photonic-enhanced spectrum management in cognitive radio networks

Abstract: Co-location of RF emitters (communications plus jammer) is a problem in tactical operations where the goal within a tactical platform is to maintain blue force communications and deny (jam) red force communications or, indeed, any red force use of spectrum. Dynamic Spectrum Access (DSA) on the DARPA neXt generation (xG) communications program [1] has a goal to sense and share spectrum for more efficient use. A port and test of this DSA capability from a commercial radio to a tactical radio showed significant improvement in tactical communications in a jamming environment.

Photonic communications device with an fm/pm discriminator and related methods

Abstract: A communications device includes a transmitter device having first and second optical sources and generating respective first and second modulated optical carrier signals at first and second optical carrier frequencies based upon an input signal. The communications device also includes an optical waveguide coupled to the transmitter device, and a receiver device coupled to the optical waveguide and including an FM-PM discriminator having a transfer function with a positive slope portion and a negative slope portion so that the first optical carrier frequency is positioned on the positive slope portion and the second optical carrier frequency is positioned on the negative slope portion.

System impacts of modulation technology and phase noise on coherent analog optical links

Abstract: We describe an analog optical link using amplitude modulation and coherent detection for high SFDR, gain, and low noise figure. We then address the dominant performance-limiting parameters and discuss several approaches to overcome these limitations.

An ontology for RF and photonic-assisted cognitive radio networks

Abstract: Automating the management of capabilities of dynamic networks (mobile ah-hoc networks or MANETs) has been addressed as a design problem. But in a network of cognitive radios, the set of manageable parameters expands the design space far in excess of current design automation or manual analysis capabilities.