SNR approach for performance evaluation of time-stretching photonic analogue to digital converter system
Alves , T. M. F.
Optics Express Vol. 19, Nº 2, pp. 1493 - 1509, January, 2011.
ISSN (print): 1094-4087
Scimago Journal Ranking: 2,58 (in 2011)
Digital Object Identifier: 10.1364/OE.19.001493
A semi-analytical simulation method (SASM) is proposed
to evaluate the signal-to-noise ratio (SNR) of time stretched signals at
the output of photonic analogue-to-digital converter (Ph-ADC) system.
Analytical expressions of the signal at Ph-ADC output considering generic
electrical signals applied to the electro-optic modulators of the Ph-ADC
are derived. The contribution to the total variance of the received signal
from the noise introduced by the electrical transmitter and receiver, and
by the optical amplifier are derived analytically taking into account the
pulsed nature of the optical signal. The proposed SASM shows excellent
agreement of SNR estimates with the estimates provided by Monte Carlo
simulation. This result is confirmed for variance dominantly imposed by
the noise introduced by the electrical transmitter, by the optical amplifier
and by the electrical receiver. A simplified approach is also proposed and
compared with previous work. It is shown that mean power estimates
obtained from this simplified approach are valid while the modulator is
operating in the linear region and the signal is not affected by the frequency
response of the electrical receiver filter. Additionally, it is concluded
that the estimates of the noise variance due to the electrical transmitter are
acceptable when a small signal analysis of noise along the Ph-ADC is valid.