Showing papers by "Robert A. Minasian published in 2014"

Instantaneous high-resolution multiple-frequency measurement system based on frequency-to-time mapping technique.

Abstract: A new microwave photonic instantaneous frequency measurement system that can simultaneously measure multiple-frequency signals while achieving very high resolution and wide frequency measurement range is presented. It is based on the frequency-to-time mapping technique implemented using a frequency shifting recirculating delay line loop and a narrowband optical filter realized by the in-fiber stimulated Brillouin scattering effect. Experimental results demonstrate the realization of a multiple-frequency measurement capability over a frequency range of 0.1–20 GHz that can be extended to 90 GHz, and with a measurement resolution of 250 MHz.

Photonic Multiple Frequency Measurement Using a Frequency Shifting Recirculating Delay Line Structure

Abstract: A new photonic frequency measurement structure that can realise multiple-frequency measurement, while simultaneously achieving a high resolution and a wide measurement range is presented It is based on successively frequency shifting the modulation sideband of an optical signal until it falls close to the reference carrier frequency, and then combining it with an unshifted carrier and detecting it through a narrowband filter Experimental results demonstrate a multiple-frequency detection capability over a range of 01–20 GHz, which can readily be extended to 100 GHz, together with a high measurement resolution of 250 MHz and small measurement error

Photonic Radio Frequency Memory Using Frequency Shifting Recirculating Delay Line Structure

Abstract: A new structure for storing a radio frequency (RF) signal utilising a fibre-optic delay line is presented. It is based on a frequency shifting recirculating delay line loop for the RF pulse storage, which prevents lasing and enables multiple recirculations and long storage time to be realised. The new photonic RF memory (PRFM) can realise a long reconfigurable storage time, wide instantaneous bandwidth and high dynamic range. Experimental demonstration of the frequency shifting loop based PRFM has been carried out for the first time, showing a long and reconfigurable storage time of more than 300 μs with high signal fidelity.

A Study of the Linearity Performance of a Stimulated Brillouin Scattering-Based Microwave Photonic Bandpass Filter

Abstract: The linearity of stimulated Brillouin scattering (SBS) is studied in detail for the first time. A closed-form expression which measures the linearity of an SBS system is derived. This expression allows one to design the region of linear operation, and the amount of Brillouin gain of an SBS system, by altering some basic system parameters. The theory presented is experimentally verified using an SBS-based microwave photonic filter structure. The effect of the length of the Brillouin medium on the linearity of the filter is investigated, and a 9.7 dB extension in the dynamic range is demonstrated by reducing the length of the fibre used as the Brillouin medium, from 25 to 0.57 km, while the filter stopband rejection level remains 30 dB.

Microwave photonic mixer with high spurious-free dynamic range.

Abstract: A new linearized photonic mixer structure, which can fully eliminate the third-order intermodulation distortion, is presented. It is based on an integrated dual-parallel Mach-Zehnder modulator to which an optimized RF split and an optimized optical phase shift are applied, in series with a Mach-Zehnder modulator driven by the LO. The mixer achieves a very high spurious-free dynamic range performance, it enables essentially infinite isolation between the RF and LO ports, and it has the ability to function over a multioctave frequency range. Experimental results demonstrate a record measured spurious free dynamic range performance of 127 dB·Hz(4/5), which is over 22 dB higher than that of the conventional dual-series Mach-Zehnder modulator-based microwave photonic mixer.

Optical-to-RF phase shift conversion-based microwave photonic phase shifter using a fiber Bragg grating

Abstract: A novel microwave photonic phase shifter structure is presented. It is based on the conversion of the optical carrier phase shift into an RF signal phase shift via controlling the carrier wavelength of a single-sideband RF-modulated optical signal into a fiber Bragg grating. The new microwave photonic phase shifter has a simple structure and only requires a single control to shift the RF signal phase. It also has the ability to realize multiple phase shifts. Experimental results demonstrate a continuous 0°–360° phase shift with low amplitude variation of <2 dB and low phase deviation of <5° over a wideband microwave range.

High-Resolution Single Bandpass Microwave Photonic Filter With Shape-Invariant Tunability

Abstract: A novel high-resolution microwave photonic signal processor is presented, which can realize single bandpass response, narrow passband characteristic, and widely tuned center frequency with shape-invariance. It realizes the single passband signal processing function within the optical link via shifting the dispersion induced RF fading of the modulated bipolar optical broadband source. The configuration can overcome the distortion in shifted dispersion induced RF fading caused by the non-uniformity in the group delay slope of dispersive delay lines. Therefore, a wider spectrum source can be used to improve the selectivity of the passband response. Experimental results verify the new proposed structure and demonstrate a shape-invariant tunable bandpass filter with a 3 dB bandwidth of 157 MHz over 0-20 GHz range.

All-Optical Frequency Shifter Based on Stimulated Brillouin Scattering in an Optical Fiber

Abstract: A new optical frequency shifter that can shift the light frequency in the microwave or millimeter-wave frequency range is presented. It is based on the use of stimulated Brillouin scattering gain and loss spectrums in an optical fiber to suppress one sideband of a double-sideband suppressed carrier modulation signal while amplifying the other sideband. The new optical frequency shifter only involves optical components and is capable of operating over a wide frequency range with low spurious generation and with tunable capabilities. It can be also used as a single-sideband suppressed carrier modulator. Experimental results demonstrate a 20 GHz frequency shift with a 25 dB signal-to-noise ratio and a widely tunable frequency shifting operation.

Wideband Microwave Photonic Downconverters with High Dynamic Range and High Conversion Efficiency

Abstract: Microwave photonic frequency conversion is a key function that is essential in many optical-wireless system applications. Photonic mixers are attractive because of the wide bandwidth potential, the high isolation between the RF and the LO ports, and the advantage of electromagnetic interference immunity. Recent new methods in wideband microwave photonic downconverters, including carrier suppression techniques that can achieve high conversion efficiency, and new linearized structures that can achieve a high spurious free dynamic range, are presented.

Recent advances in single bandpass microwave photonic filtering

Abstract: We describe recent advances in the field of microwave photonic signal processing, with a focus on single bandpass filtering approaches that overcome spectral periodicity and achieve wideband frequency operating range.

Nonlinear stimulated Brillouin scattering based photonic signal processors

Abstract: Recent new methods in photonic signal processing based on stimulated Brillouin scattering, that enable the realization of photonic mixers with high conversion efficiency, ultra-wide continuously tunable high-resolution microwave photonic filters and programmable switchable microwave photonic tunable filters, are presented. These processors provide new capabilities for the realisation of high-performance and high-resolution signal processing.