SSII cancellation in an EAM-based OFDM-IMDD transmission system employing a novel dynamic chirp model

Abstract

We develop a novel subcarrier-to-subcarrier intermixing interference (SSII) cancellation technique to estimate and eliminate SSII. For the first time, the SSII cancellation technique is experimentally demonstrated in an electro-absorption modulator- (EAM-) based intensity-modulation-direct-detection (IMDD) multi-band OFDM transmission system. Since the characteristics of SSII are seriously affected by the chirp parameter, a simple constant chirp model, we found, cannot effectively remove the SSII. Therefore, assuming that the chirp parameter linearly depends on the optical power, a novel dynamic chirp model is developed to obtain better estimation and cancellation of SSII. Compared with 23.6% SSII cancellation by the constant chirp model, our experimental results show that incorporating the dynamic chirp model into the SSII cancellation technique can achieve up to 74.4% SSII cancellation and 2.8-dB sensitivity improvement in a 32.25-Gbps OFDM system over 100-km uncompensated standard single-mode fiber.

Iterative nonlinear ISI cancellation in optical tilted filter-based Nyquist 4-PAM system

“…The square of the absolute value of signal is the reconstructed intermixing term. The calculated nonlinear ISI is the product of the weighting factor and the sum of beating and intermixing terms, where the weighting factor is obtained by using least squares error [17]. Then the received data after the nonlinear ISI cancellation are demodulated again to get the more accurate detected data.…”

Iterative intersymbol interference cancellation in vestigial sideband Nyquist–subcarrier modulation system

“…IFFT and FFT require ð2NÞ × log 2 ð2NÞ complex multiplications, and the nonlinear ISI calculation requires ð2NÞ × log 2 ð2NÞ complex multiplications. 15,19 Thus, the extra computational complexity of ð4NÞ × log 2 ð2NÞ is required for each iteration.…”

“…A conventional electrical dispersion compensation method, overlap FDE (O-FDE), 8 is used to compensate the linear distortion. An iterative distortion cancellation technique used in an orthogonal frequency division multiplexing system [15][16][17] is introduced to mitigate the nonlinear ISI. Furthermore, we have experimentally demonstrated a 40-Gbps 16-quadrature amplitude modulation (QAM) MachZehnder modulator (MZM)-based VSB-IMDD half-cycle Nyquist-SCM system transmission over a 100-km uncompensated standard single-mode fiber (SSMF) with iterative nonlinear ISI cancellation.…”

40-Gbps vestigial sideband half-cycle Nyquist subcarrier modulation transmission experiment and its comparison with orthogonal frequency division multiplexing

“…[1][2][3] Optical OFDM has been widely explored in systems with both coherent detection and direct detection (DD) due to its advantages in overcoming transmission impairments such as chromatic dispersion (CD) and polarization-mode dispersion. Nyquist modulation is well known from communication theory and has been widely studied in coherent Nyquist-WDM systems in recent years, but is relatively new in DD systems.…”