No abstract

International audienceThe key goal of this paper consists of a theoretical and an experimental performances analysis of a photonic microwave mixer used as a signal down- and up-converter based on cross-gain modulation in a semiconductor optical amplifier (SOA). We give, by a small-signal analysis approach, the analytical equations of the output optical power carrying the down- and up-converted signal. Simplified formulas are developed, relating the mixing conversion gain to the modeling parameters of the SOA. The efficiency of the photonic microwave mixer based on an SOA has been evaluated in terms of mixing conversion gain, third-order input intercept point, and electrical phase noise. In addition, a subcarrier modulated by a QPSK, a 16 quadratic-amplitude modulation (QAM) and a 64 QAM at a data rate of 270 ksymb/s has been down converted from 1 GHz to 100 MHz with a low error vector magnitude of about 3.5%

In this paper, a numerical model of Semiconductor Optical Amplifiers (SOA) is experimentally validated in terms of the Alpha Factor and the Four-Wave Mixing (FWM). Besides, a Coherent Optical-Orthogonal Frequency Division Multiplexing (CO-OFDM) simulation platform is used to confirm the good agreement between the measured and the simulated Error Vector Magnitude (EVM) of a received signal amplified by the studied SOA in an optical transmission link. In addition, the performance of the SOA on the amplification of a 10.94 Gb/s QPSK CO-OFDM signal is numerically analyzed with respect to the Amplified Spontaneous Emission (ASE) noise, the Alpha Factor, the output saturation power of the SOA and the bit rate. Index Terms-Advanced modulation formats, coherent optical-OFDM, four wave mixing (FWM), phase-amplitude coupling, semiconductor optical amplifier (SOA).

Up and down frequency conversions in the range of 0.5-39.5 GHz are performed by using a Semiconductor Optical Amplifier-Mach-Zehnder interferometer (SOA-MZI) in a differential configuration as a sampling mixer. The authors show that increasing the sampling frequency by a ratio of 2.5 (from 7.8 to 19.5 GHz) improves the efficiency and the quality of the optical transmission of QPSK and OFDM signals due to a better signal level and a lower aliased noise power when the sampling rate is higher. At the high sampling rate, the obtained EVM is sufficiently low for allowing data bit rates higher than 1 Gbit/s and 245 Mbit/s, respectively, for QPSK and OFDM modulated data.

No abstract

International audienc

No abstract

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.