Power Efficient Communications Employing Phase Sensitive Pre-Amplified Receiver
Journal article, 2022

The receiver sensitivity is a very important metric in optical communication links operating at low received signal powers. Phase sensitive optical amplifiers (PSAs) can amplify optical signals without excess noise, thus providing a fundamental sensitivity improvement of 3 dB when employed as a pre-amplifier compared to conventional erbium doped fiber amplifiers (EDFA). In this paper, we investigate, both theoretically and experimentally, the sensitivities achieved using power efficient multi-dimensional modulation formats such as M-ary pulse position modulation format (M-PPM) and M-PPM combined with quadrature phase shift keying (QPSK) along with a near-noiseless PSA pre-amplified coherent intradyne receiver. We find that at high signal to noise ratios (SNRs) corresponding to low bit-error-rates (BER), M-PPM+QPSK results in the best sensitivity, which is improved with the order M, while at low SNRs corresponding to high BER (~14% where 100% overhead forward error correction codes (FEC) would be needed to recover the data), QPSK is the most sensitive format, while at the same time providing the best spectral efficiency. We report experimental sensitivities of 2.1 photons per information bit (PPB) at a pre-FEC BER=10-3 using 64-PPM+QPSK and assuming 7% FEC, and 0.8 PPB at a pre-FEC BER= 0.14 using QPSK and assuming 100% FEC.

Phase shift keying

Modulation format


Receiver sensitivity

Pulse position modulation

Forward error correction

Phase sensitive amplifier


Noise measurement

Bit error-rate

Signal to noise ratio



Ravikiran Kakarla

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

Mikael Mazur


Jochen Schröder

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

Peter Andrekson

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

IEEE Photonics Technology Letters

1041-1135 (ISSN) 19410174 (eISSN)

Vol. 34 1 3-6

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