Showing papers by "Richard DeSalvo published in 2009"

High performance microwave photonic links using double sideband suppressed carrier modulation and balanced coherent heterodyne detection

Abstract: Optical transmission of microwave signals offers many advantages such as increased bandwidth; immunity to electromagnetic interference; reduction of size, weight and power consumption; and low, frequency-independent loss over long distances. But microwave photonic links often lack the performance required to replace traditional microwave links. We present a microwave photonic link architecture that enables high gain and dynamic range, low noise figure, and multi-octave bandwidth operation. Our method uses double sideband suppressed carrier modulation together with a balanced coherent heterodyne detection scheme. The modulation method increases link linearity by producing amplitude modulation based on the optical field rather than intensity. The combination of carrier suppression, optical amplification, phase-locked local oscillator insertion, and balanced detection provide high signal-efficient gain, reduced intermodulation distortion, wide-band operation, and low link noise. The resulting link places this microwave photonic approach in the same performance realm as state-of-the-art microwave links.

Balanced coherent heterodyne detection with double sideband suppressed carrier modulation for high performance microwave photonic links

Abstract: Optical transmission of microwave signals offers many advantages such as increased bandwidth; immunity to electromagnetic interference; reduction of size, weight and power consumption; and low, frequency independent loss over long distances. But microwave photonic links often lack the performance required to replace traditional microwave links. We present a microwave photonic link architecture that enables high gain and dynamic range, low noise figure, and multi-octave bandwidth operation. Our method uses double sideband suppressed carrier (DSB-SC) modulation together with a balanced coherent heterodyne detection scheme. The modulation method increases link linearity by producing amplitude modulation based on the optical field rather than intensity. The combination of carrier suppression, optical amplification, phase-locked local oscillator insertion, and balanced detection provide high performance microwave photonic links.

Suppressed carrier techniques for multi-octave high dynamic range microwave photonic links

Abstract: Optical transmission of microwave signals offers many advantages such as increased bandwidth, immunity to electromagnetic interference, reduction of size and weight, and minimal loss over long distances. But microwave photonic links often lack the sufficiently high dynamic range and large instantaneous bandwidth required in many applications. Optical carrier suppression has been used to increase link dynamic range, but second harmonic distortion terms limit the operational bandwidth to sub-octave applications. We present a method to apply carrier suppression to microwave photonic links while maintaining multi-octave operation. Our technique uses double sideband suppressed carrier modulation together with coherent heterodyne balanced detection to increase dynamic range, eliminate bandwidth-limiting second-order distortion terms, and reduce link noise figure. This approach provides efficient amplification of the modulated signal while limiting the effect of shot noise from the source laser and reducing common-mode noise terms such as source laser RIN and amplifier-related beat noise.

RF photonic notch filters in high dynamic range links

Abstract: Optical implementation of RF filtering provides processing and switching advantages for analog optical links, bringing additional versatility to the field of RF photonics. Many RF photonic notch filter designs have demonstrated this increased link functionality, but most techniques are sensitive to polarization and phase noise, and are tunable over limited ranges, set by the tunability limits of conventional link components such as DFB lasers. We demonstrate an RF photonic notch filter with extremely wide tunability, high extinction ratio, and large range of useable bandwidths as part of a high dynamic range RF photonic link. We discuss methods for improved filter operation, present experimental results for X-band operation of the filter, and describe its use in applications such as co-site interference mitigation.