Open AccessAccurate control of optoelectronic amplitude to phase noise conversion in photodetection of ultra-fast optical pulses
Author(s) -
Romain Bouchand,
Daniele Nicolodi,
Xiaopeng Xie,
Christophe Alexandre,
Yann Le Coq
Publication year - 2017
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.25.012268
Subject(s) - photodetection , photodetector , optics , photodiode , phase noise , optoelectronics , noise (video) , physics , demodulation , laser , relative intensity noise , phase modulation , materials science , semiconductor laser theory , telecommunications , computer science , channel (broadcasting) , artificial intelligence , image (mathematics)
When illuminating a photodiode with modulated laser light, optical intensity fluctuations of the incident beam are converted into phase fluctuations of the output electrical signal. This amplitude to phase noise conversion (APC) thus imposes a stringent constraint on the relative intensity noise (RIN) of the laser carrier when dealing with ultra-low phase noise microwave generation. Although the APC vanishes under certain conditions, it exhibits random fluctuations preventing efficient long-term passive stabilization schemes. In this paper, we present a digital coherent modulation-demodulation system for automatic measurement and control of the APC of a photodetector. The system is demonstrated in the detection of ultra-short optical pulses with an InGaAs photodetector and enables stable generation of ultra-low phase noise microwave signals with RIN rejection beyond 50 dB. This simple system can be used in various optoelectronic schemes, making photodetection virtually insensitive to the RIN of the lasers. We utilize this system to investigate the impact of the radiofrequency (RF) transmission line at the output of the photodetector on the APC coefficient that can affect the accuracy of the measurement in certain cases.