3.1 Low noise amplifiers

Optical amplifiers are key devices used in a wide range of applications such as optical communications, photon detection, optical processing, and laser physics to compensate passive loss, increase power level or enhance receiver sensitivity. To date all commercialized optical amplifiers are phase-insensitive (PIA), which amplify the two orthogonal quadratures of the input signal equally. This type of optical amplifier is characterized by the well-known 3 dB quantum-limited noise figure (NF) and will thus degrade the output signal-to-noise ratio (SNR) by adding excess noise. Deterministic noise-less linear amplification can only be realized by phase-sensitive amplifiers (PSAs). Such an amplifier requires phase-locked signal and idler being present at the input, and amplifies the in-phase quadrature while deamplifying the out-of-phase quadrature, leading to a 0 dB NF of the in-phase component.


Our group has developed strong activity in the analysis of the noise properties of phase sensitive amplifiers mainly in the context of the EU project PHASORS. In collaboration with other leading groups in Europe, we managed to demonstrate phase sensitive amplification with 26 dB gain and noise figure equal to 1 dB. Now, we consider the exploitation of the PSA technology in niche applications in telecom and sensing where shot noise limited signals are hitting the receiver. 


Related projects:



Significant publications:

  • A. Bogris, D. Syvridis, P. Kylemark and P. A. Andrekson, “Noise characteristics of dual-pump fiber-optic parametric amplifiers,” J. Lightwave Technol. vol. 23, pp. 2788-2795, Sep. 2005.
  • P. Velanas, A. Bogris, D. Syvridis, “Impact of Dispersion Fluctuations on the Noise Properties of Fiber Optic Parametric Amplifiers,” IEEE Journal of Lightwave Technology, vol. 24, pp. 2171-2178, May 2006.
  • Adonis Bogris, Dimitris Syvridis, and Costas Efstathiou, “Noise Properties of Degenerate Dual Pump Phase Sensitive Amplifiers,” IEEE Journal of Lightwave Technology, vol. 28, No. 8, pp. 1209-1217, April 2010.
  • Z. Tong, C. Lundström, A. Bogris, M. Karlsson, P. Andrekson, D. Syvridis, “Measurement of Sub-1dB Noise Figure in a Non-Degenerate Cascaded Phase-Sensitive Fibre Parametric Amplifier,” ECOC 2009, Vienna.