A dual-detector optical heterodyne receiver for local oscillator noise suppression

Novel ring resonator-based optical beamformer for broadband phased array receive antennas

“…Therefore, the unmodulated optical carrier must be reinserted before optical detection. Balanced detection is used instead of direct single-ended detection, because it enhances the dynamic range of the system [4], [8].…”

Analysis of Analog Photonic Links Employing Multiple-Channel (Arrayed) Receivers

“…It is well known that the addition of an optical amplifier (EDFA) raises the electrical noise floor in both digital and analog applications [6,7] due to the presence of amplified spontaneous emission (optical) noise. To mitigate this additional noise in systems employing EDFAs prior to modulation, dual-output optical modulators and balanced-detection [8,9] are frequently employed. This technique has been utilized alone to achieve the first multi-gigahertz bandwidth analog optical link with a noise figure < 10 dB [10] and in concert with other techniques to achieve an RF noise figure approaching 3 dB [11].…”

Coherent optical array receiver for PPM signals under atmospheric turbulence

“…There are two main advantages; first of all, since the balanced receiver generates the difference between the noise processes in the two photodetectors, this results in a cancellation of any correlated noise terms that appear in the two detectors. Intensity fluctuations that appear due to RIN in the local oscillator laser (LO) are correlated in the two photodetectors and are cancelled (Abbas et al, 1985).…”

“…In order to achieve good wideband noise cancellation, it is critical to obtain a stable and accurate balance (Alexander and Stephen, 1997) between both photocurrents and also to have equal paths from the optical coupler to the each photodetector (Abbas et al, 1985 andAlexander, 1987). In practice, it is easy to achieve shot noise limited performance using this configuration (Henry andPersonick, 1990 andAbbas et al, 1985).…”