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Linear Photonic RF Front-End Technology (PHOR-FRONT)

The objective of Lineaer Photonic RF Front-End Technology (PHOR-FRONT) is to provide a universal photonic radio frequency (RF) front-end that helps bring the vision of high dynamic range and high instantaneous bandwidth (IBW) RF-to-bits receivers to fruition. More specifically, the PHOR-FRONT program will develop and demonstrate the photonic modules deemed most critical in achieving the noise figure (NF) and spurious-free dynamic range (SFDR) requirements for dramatically improved RF front-ends. It has been determined that a coherent analog photonic link is the most promising approach to enable the required RF system performance. PHOR-FRONT exploits the linear electro-optic effect, which converts an RF voltage signal into a phase modulated optical signal with "perfect" linearity. PHOR-FRONT components will show a clear path to supporting the following system specifications for RF center frequencies from 0.5-18 GHz: > 90 dB 2-tone SFDR in 500 MHz IBW and 3 dB NF. The resulting link will be capable of supporting a signal-to-noise ratio (SNR) of approximately 175 dB (normalized to 1 Hz bandwidth).

It has been determined that a coherent analog photonic link is the most promising approach to enable the required RF system performance...

PHOR-FRONT development is divided between two main thrust areas: a 1550 nm coherent optical oscillator and a linear optical phase demodulator. The high-power, low-noise and narrow-linewidth laser required to approach the required SNR ratio while maintaining a 3 dB NF is an extremely challenging task and mandates significant innovation. The linear phase demodulator is equally challenging, with the goal being to demodulate the coherent phase-modulated signal with "perfect" linearity. Furthermore, the components and subsystems developed in PHOR-FRONT will be designed to be suitable for on-board processing within air, ground, or maritime military platforms.