High-Gain, Low-Noise-Figure, and High-Linearity Analog Photonic Link Based on a High-Performance Photodetector

We report a high-gain, low-noise-figure, and high-linearity analog photonic link. The link combines a high-power and low-noise fiber laser, a Mach-Zehnder modulator, a high-gain erbium-doped fiber amplifier (EDFA), and a high-performance charge-compensated modified unitraveling-carrier photodiode. The critical characteristics of the photodiode include 16-GHz bandwidth, 200-mA saturation current, and >35 dBm third-order intercept point. In the link, low biasing is utilized to reduce the noise and maximize the signal-to-noise ratio, and an EDFA is used to provide sufficient optical input to the MUTC photodiode to ensure that the link can achieve high gain and high output RF power. The combination of high-power low-noise fiber laser and high-bandwidth high-power photodiode, we have enabled high gain (27.8 dB at 6 GHz and 24.5 dB at 12 GHz), low noise figure (4.7 dB at 6 GHz and 6.9 dB at 12 GHz), and high spur free dynamic range (>120 dB · Hz^2/3) in the frequency range 6-12 GHz.