Noise figure of parametric wavelength conversion with quasi-phase-matched LiNbO/sub 3/ waveguide

An analytical model of the noise accumulation in a chain of parametric wavelength converters is proposed. Signal-to-noise electrical power ratio is analytically given as a function of node number k in a chained transparent node system that consists of optical amplifiers, parametric wavelength converters, and several loss elements including optical transmission fiber with parameters of pump light excess noise beta
_p
, and average photon numbers per unit time of pump light and input signal langn
_p
rang, and langn
₀
rang, respectively, and spontaneous emission factor of optical amplifier n
_sp
. The signal-to-noise degrades inversely proportional to node number k with the coefficient defined by NF
⁽¹⁾
=2n
_sp
+beta
_p
langn
₀
rang/langn
_p
rang when k is lower than langn
₀
rang/Bo, where B
_o
represents optical bandwidth. The noise figure dependence on pump light quality beta
_p
/langnprang and average photon number of input light langn
₀
rang in a single stage configuration are experimentally evaluated using Er-doped fiber amplifiers and quasi-phase-matched lithium niobate waveguide parametric wavelength conversion