Shane J. Strutz

An 8-18-GHz all-optical microwave downconverter with channelization

A wide-band fiber-optic image-rejection downconverter capable of channelizing received signals into a 500-MHz intermediate frequency band is demonstrated. The downconverter utilizes phase modulators to convert received signals into optical side-bands prior to heterodyne detection with the system local oscillator. Experimental measurements performed on a two-channel system which maps 8-18-GHz signals into intermediate frequencies between 2 and 2.5 GHz reveal an image rejection of 20 dB and a spur-free dynamic range of 107 dB/Hz/sup 2/3/.

110 km 256-QAM digital microwave over fiber link

A 110 km digital microwave fiber-optic link has been designed and demonstrated with 256 QAM at 20 GHz. The design approach, involving the management of loss, dispersion, and Brillouin threshold throughout the link is discussed.

A 0.8-8.8-GHz image rejection microwave photonic downconverter

We report the performance of a wideband image rejection microwave downconverter which maps 0.8-8.8 GHz signals into intermediate frequencies between 1-2 GHz. Measurements performed on the system reveal an image rejection of greater than 150 dB and a spur free dynamic range of 106 dB/Hz/sup 2/3/. In addition, spurious signals present in the original system have been removed.

Demonstration of a wide-band image rejection microwave downconverter

A photonic image-rejection downconverter capable of down-converting radio-frequency (RF) signals over a range of 5-18 GHz into an IF band 2.1 GHz wide (3.3-5.4 GHz) is presented. RF signals received by the system are first up-converted into the passband of a 21.3-23.4-GHz filter, and then optically down-converted to 3.3-5.4 GHz. The system exhibited better than 60 dB of image rejection over its entire bandwidth and spurious signals resulting from harmonic mixing products were more than 25 dB below the downconverted signal.

Polarization-maintaining hybrid erbium-Brillouin amplifier for high-power low-noise sources

A low-noise high-power source incorporating a polarization-maintaining erbium-Brillouin fiber amplifier is presented. The output noise power is analyzed and a theoretical noise spectral density is determined. Shot-noise-limited performance is predicted and experimentally achieved within the 1-8-GHz-offset frequency range. The polarization extinction ratio was measured as 25 dB.

A high-power, low-noise polarization maintaining Erbium/Brillouin fiber amplified source

A polarization maintaining erbium/Brillouin fiber amplifier was investigated. The output noise of the amplified source was measured and compared to shot-noise. Shot-noise limited performance was achieved within the 1 GHz to 8 GHz frequency band.