Thierry Rampone

Performances of a Photonic Microwave Mixer Based on Cross-Gain Modulation in a Semiconductor Optical Amplifier

The 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%.

Semiconductor optical amplifier used as an in-line detector with the signal DC-component conservation

We present in this paper a dc-coupled in-line optical detector based on a multisection semiconductor optical amplifier (SOA). The key principle is to use a voltage reference correlated with the bias voltage level by the way of a two-section or a three-section SOA. So, by means of the differential detection, the signal dc-component is kept with reduced sensitivity to temperature and bias current fluctuations. Experimental and theoretical results are presented when a two-section SOA is used and performance predictions when a three-section is employed. The obtained responsivity is -63 VNV at 40 mA and over -110 VNV at 50 mA when the input optical power, measured within the fiber, is -13 dBm. When the SOA is biased at 40 mA, the detection bandwidth is over 1 GHz when the input optical power is -4 dBm.

Experimental Validation of Numerical Simulations and Performance Analysis of a Coherent Optical-OFDM Transmission System Employing a Semiconductor Optical Amplifier

In this paper, a numerical model of Semiconductor Optical Amplifiers (SOA) is experimentally validated in terms of the Alpha Factor (αH) 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.

Experimental and Simulation Analysis of the Third-Order Input Interception Point in an All-Optical RF Mixer Based on a Semiconductor Optical Amplifier

We present an experimental and computing analysis of the nonlinear distortions of an all-optical radiofrequency mixer based on cross-gain modulation (XGM) in a semiconductor optical amplifier (SOA). Such an all-optical mixer is well suited for radio-over-fiber (RoF) applications. The simulation results are based on a SOA model developed under ADS™ software and are compared to experimental results in various cases. The good correlation between experimental and simulation results permits to demonstrate the ability of our SOA model to study mixing phenomenon by using a Harmonic Balance (HB) simulation method. Optical third-order input intercept point (IIP3) and its electrical equivalent are determined experimentally and by simulation with a good concordance. An optical IIP3 of -5 dBm and a spurious free dynamic range (SFDR) of 85.7 dB/Hz are obtained for a radiofrequency signal at 1 GHz. Moreover, simulations show that the IIP3 increases, all other parameters being equal, when the SOA active zone is shortened.

Semiconductor Optical Amplifiers in Coherent Optical-OFDM Systems

Experimental results of using a semiconductor optical amplifier (SOA) for amplification of a coherent optical-orthogonal frequency-division-multiplexing (CO-OFDM) transmission system are presented. The impact of the SOA nonlinearities on the amplification of a 10.94-Gb/s quadrature phase-shift keying CO-OFDM signal with respect to the input power, the signal wavelength, and the number of subcarriers is investigated.

Optical Radiofrequency Signal Mixing by All-Optical Sampling Based on a Semiconductor Optical Amplifier Mach–Zehnder Interferometer

Experimental performances analysis of an optical radiofrequency signal mixer based on a semiconductor optical amplifier Mach-Zehnder Interferometer utilizing an all-optical sampling method is presented. An optical pulse source generating 21-ps width pulses at a repetition rate of 7.8 GHz samples an intensity-modulated optical carrier carrying an electrical subcarrier at the intermediate frequency 1 GHz. The efficiency of the all-optical radiofrequency mixer is evaluated in terms of mixing conversion gain and third-order input intercept point. The conversion gain varies from 14.4 dB to 20.3 dB according to the chosen frequency. In addition, the electrical subcarrier modulated by a Quadrature phase shift keying (QPSK) and a 16-quadrature amplitude modulation (QAM) signal at a data rate of 1 MSymb/s has been frequency up-converted up to 40 GHz with an error vector magnitude of 11.68% for the QPSK modulation and 10.94% for the 16-QAM.

Down-Conversion Gain of an All-Optical SOA-MZI-Based Mixer Using Bandpass Sampling

The frequency conversion is one function of utmost importance in radio over fiber technologies. In this letter, we propose an optical implementation of a radio frequency down conversion based on a bandpass sampling technique realized by a semiconductor optical amplifier Mach-Zehnder interferometer used as an optical signal sampler. An optical pulse source generating 23-ps width pulses at a repetition rate of 7.8 GHz is employed to sample an intensity-modulated optical carrier carrying the signal to be frequency down converted. The frequency down conversion from a radio frequency signal at 37 GHz to an intermediate frequency at 2 GHz shows a positive conversion gain of 4 dB.

Effects of assist light injection at gain transparency wavelength on transmission and performances of SOAs

In this paper, we have demonstrated that the injection of a CW assist light high power into the SOA cavity at the gain transparency wavelength improves the SOA saturation output power, accelerates the dynamic gain recovery time and reduces the optical signal waveform distortion