Suppression of Even-Order Photodiode Nonlinearities in Multioctave Photonic Links

Field Test on the Feasibility of Remoting HF Antenna with Fiber Optics

“…The installation process of the link has been described, specifically noting that phase matching of the link must be performed. A complete technical report on the link design and proof-of-concept experiments is provided in [1], with a more-detailed description of the novel fiber-optic receiver provided in [3]. The primary results of this report are that the RF performance metrics measured in the field agree with those reported in [1] and that accurate direction-finding capability has been demonstrated.…”

“…As shown in Figure 3(b), the four optical outputs on the transmitter are connectorized using FC/APC connections for mating to the fiber-optic cable. The receiver has four FC/APC-terminated optical inputs, which feed to a custom photodiode array that minimizes even-order distortions [1], [3]. The RF output of the receiver feeds an analog-to-digital converter (ADC) or other equipment defined by the user.…”

The performance of unbiased balanced photodiodes for optical calibration of radio-frequency antenna arrays

“…We have previously demonstrated that reversed-biased balanced photodiodes will suppress photodiode-induced even-order distortion for RF-over-fiber applications [4]. In this work, we demonstrate a 26-dB increase in second-order output intercept point (OIP2) in unbiased balanced photodiodes for array calibration applications.…”

Optical Comb Sources and High-Resolution Optical Filtering for Measurement of Photodiode Harmonic Distortion

“…Diverse applications ranging from optical signal processing [1] and optical analog-to-digital conversion [2] to antenna remoting [3], [4] continue to drive enhanced link performance. In conventional externally intensity-modulated direct-detection (IMDD) analog optical links employing Mach-Zehnder intensity modulators (MZMs), link performance is predominantly determined by two quantities-the efficiency of the MZM and the average received photocurrent [5], [6].…”

“…While these techniques have been utilized to achieve spur(ious)-free dynamic ranges in excess of 130 dB (in a 1-Hz bandwidth), such demonstrations have only been performed in modest-photocurrent links ( mA). As the average current is increased to improve link performance, nonlinearities in the photodiode (PD) will eventually surpass those of the MZM [4]. Therefore, it is increasingly important to look beyond the well-understood nonlinearity of Mach-Zehnder modulators to quantify and, eventually, mitigate the nonlinearity of other components-of particular interest are the photodiodes utilized in the receiver.…”