Reginaldo Silva

Enhanced digital polarization demultiplexation via CMA step size adaptation for PM-QPSK coherent receivers

Fixed step size CMA can exhibit serious penalties due to rapid channel variations during coherent receiver polarization demultiplexing. We propose and experimentally demonstrate two CMA gain adaptation methods that improve dynamic equalizer tracking and convergence.

Achievable Rates of Space-Division Multiplexed Submarine Links Subject to Nonlinearities and Power Feed Constraints

We study the achievable rates of submarine fiber systems in the high-dimensional design space of variables including span length, launch power, number of spatial channels, and power feed current. We identify the regimes in which nonlinearities or power feed equipment constraints become dominant, and demonstrate that optimized system design evolves toward the linear regime as the system scales to a high number of spatial channels. We calculate the bit rate achievable by uniform and probabilistically shaped M-ary Quadrature Amplitude Modulation constellations to identify potential capacity-achieving implementations.

448 Gb/s Dual-Carrier PDM-RZ-16QAM on 75-GHz Grid over 720 km with 10 Flexi-Grid ROADM passes

We show 448 Gb/s transmission of dual-carrier pre-filtered PDM-RZ-16QAM modulation in 75-GHz flexi-grid channel spacing over 720 km and 10 ROADM passes with 5.97-b/s/Hz spectral efficiency.

112 Gb/s DP-QPSK coherent optical transmission over 3000 km using an complete set of digital signal processing algorithms

Digital signal processing is a key feature in coherent dual polarization QPSK optical transmission, and plays an essential role to determine system performance. In this paper, we present a set of signal processing algorithms able to recover a single channel 112 Gb/s DP-QPSK signal after 3000 km propagation in a recirculation loop. The OSNR resilience and optical filtering impact over maximum reached distance were also investigated.

Potential for 1550-nm broadband amplification by using different Er 3+ - doped tellurite fiber structures

A spectral analysis of two Er3+- doped tellurite fiber structures pumped at 980-nm is presented. The samples produced bandwidths in the order of 95 nm around 1550 nm and potential amplification up to 15 dB.

Improved Receiver Sensitivity by Using an Injection-Locked Laser and Double-Pass EDFA Scheme

This work investigates a coherent receiver that uses a single-facet optical injection-locked semiconductor laser embedded into a doubled-pass EDFA. Consequently, receiver sensitivity as low as -65 dBm is possible with this low noise combined scheme.

A comparative analysis of doubled-pass erbium doped fiber amplifiers considering different signal-return schemes

In this work, an experimental comparative analysis of doubled-pass erbium doped fiber amplifiers with different signal-return approaches is presented. The amplifier performance was investigated in terms of gain and noise figure as the signal under amplification was reflected back towards the erbium doped fiber by a mirror, filter, or circulator arrangement. Also, a semiconductor laser under single-facet optical injection locking was tried as an equivalent reflexive element. In particular, the regenerative characteristics provided by the injection locking process were able to provide considerably high gain and low noise figure levels for the amplifier, especially for considerably low input signal power.