A theoretical and experimental performance analysis of a Semiconductor Optical Amplifier -Mach-Zehnder Interferometer (SOA-MZI) photonic sampling mixer used as a frequency up-converter is presented employing Switching and Modulation architectures. An active mode-locked laser, generating 2 ps-width pulses at a repetition rate equal to 10 GHz, is used as a sampling source. An optical carrier intensity modulated by a sinusoidal signal at 1 GHz is up-converted to 9 GHz and 39 GHz. High Conversion Gains (CGs) of about 15 dB are demonstrated for the frequency conversion to 9 GHz using both architectures, whereas up to 4 dB and 9 dB for the conversion to 39 GHz employing Switching and Modulation architectures, respectively. Small-signal equations for the up-converted signal in both architectures are formulated and developed, which permit to quantify the CG from closed-form expressions. The numerically calculated CG values are in very good agreement with those obtained experimentally. The validated equations are subsequently employed to explain the performance differences between the two architectures in terms of the CG. Furthermore, signals modulated by QPSK and 16-QAM complex modulation formats at different baud rates are up-converted from 750 MHz to 9.25 GHz and 39.75 GHz and their Error Vector Magnitude is evaluated and compared. The maximum bit rate that meets the Forward Error Correction (FEC) limit is achieved using the Modulation architecture. It is 1 Gbps and 512 Mbps for QPSK and 16-QAM modulations, respectively.

An experimental comparison of the conversion gain and harmonic distortion performance between Switching and Modulation architectures of an all-optical photonic sampler mixer up-converter using a Semiconductor Optical Amplifier-based Mach-Zehnder Interferometer (SOA-MZI) is presented. The process of frequency up-conversion from 1 GHz to 9 GHz is evaluated. Because of their different principle of operation, the Switching architecture demonstrates higher positive conversion gain by approximately 6 dB and 8 dB for standard and differential configuration, respectively, while the Modulation architecture achieves lower harmonic distortion up to 8 dB, depending on the modulation index of the 1 GHz signal.

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We present a post-distortion linearization technique for a semiconductor optical amplifier Mach-Zehnder interferometer (SOA-MZI) photonic sampler. The sampling source is an active mode-locked laser producing 12.6 ps-width pulses with a repetition frequency of 10 GHz. The mathematical model for the linearization technique is presented and then evaluated for the quasi-static regime, i.e. sampling continuous-wave signals, and for the dynamic regime, i.e. sampling sinusoidal signals. A significant improvement in terms of total harmonic distortion (THD) equal to 23.4 dB is observed for a modulation index equal to 80% in the quasi-static regime, matching the highest observed THD improvement in the dynamic regime.

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