Optimization of intersatellite microwave photonic links by utilizing an optical preamplifier under dual-tone modulation

Abstract

An optical preamplifier is utilized to improve the signal-to-noise and distortion ratio (SNDR) of intersatellite microwave photonic links employing a Mach-Zehnder modulator under dual-tone modulation. The resulting SNDR at an appropriate direct current (DC) bias phase shift is additionally investigated without small-signal approximation in order to optimize the performance of all the links. It is observed that the most limiting factor degrading the SNDR performance is changed, and the fundamental power is seen to increase more compared with the power of third-order intermodulation (IM3) plus noise due to the optical preamplifier. Thus, SNDR can be improved with respect to the case of a nonoptical preamplifier. For the preamplifier gain of 20 dB and noise figure of 3 dB, an increase of about 24 dB in optimum SNDR is accessible. In addition, the optimum DC bias phase shift is found to be insensitive to the preamplifier gain and noise figure, while the optimum SNDR is sensitive to the preamplifier gain and noise figure.

Performance comparison of analogue inter‐satellite microwave photonics link using intensity modulation with direct detection and phase modulation with interferometric detection

“…However, the influence of an optical booster amplifier and optical preamplifier on the performance of both links has not been considered. Furthermore, the intensity modulator biased at the quadrature point is not optimum for amplified analogue inter-satellite microwave photonics link, which has been demonstrated in our earlier work [11,12].…”

“…The exact analytical solution of modulator output power can be obtained as [11] (see (1) below) where α is the insertion loss of DD-MZM, m = πV/2V π is the modulation index of modulator, V = 2P rfin Z in is the amplitude of input RF signal, P rfin is the input RF signal power, Z in = 50 Ω is the link input impedance, V π is the switching voltage of modulator, w rf is the angular frequency of input RF signal, θ is the direct current (DC) bias phase shift, P optin is the laser output power and J M (·) is the Bessel function of first kind with order M.…”

Impact of pointing errors on performance of an intersatellite microwave photonics link with an optical preamplifier under dual-tone modulation

“…In our previous work [12], we presented an analogue intersatellite microwave photonics link model using an external modulator with both an optical booster amplifier and an optical preamplifier, which is a novel system configuration for long-distance highloss intersatellite telecommunication applications. In an extension of the previous work described earlier, we include the effect of a random pointing jitter in the performance analysis, which proves to be significant.…”

“…We have demonstrated that the beat noise between the signal field and the amplifier spontaneous emission (ASE) noise arising from the optical preamplifier, the thermal-Johnson noise, and the selfmixing ASE noise are the main noise components in an analogue intersatellite microwave photonics link [12]. The thermal-Johnson noise is given by…”

“…However, these works focus on the performance of a direct modulation digital intersatellite link without considering the effect of IMD3. We studied the SNDR of an intersatellite microwave photonics link with an optical preamplifier affected by IMD3 while the pointing errors were not taken into account [12]. To the best of our knowledge, the combined effects of IMD3 and pointing errors on the performance of an intersatellite microwave photonics link with an optical preamplifier has never been addressed in the past.…”