Napoleão S. Ribeiro

Hundred-Picoseconds Electro-Optical Switching With Semiconductor Optical Amplifiers Using Multi-Impulse Step Injection Current

An ultrafast electro-optical amplified switch based on chip-on-carrier semiconductor optical amplifier with high optical contrast (33 dB) is presented. Switching times up to 115 ps with small overshoot were achieved by using the multi-impulse step injected current technique. These results are compared with previous preimpulse step injected current technique, and achieve a reduction of the inherent, post switching gain fluctuations without worsening the switching times. In addition, pulse formats for controlling such a kind of electro-optical switches are numerically analyzed and compared with experiments.

Rise Time and Gain Fluctuations of an Electrooptical Amplified Switch Based on Multipulse Injection in Semiconductor Optical Amplifiers

Subnanosecond electrooptical switching times with 26-dB extinction ratio were obtained by using semiconductor optical amplifiers driven by a multipulse injection current. The multipulse switching current was generated by superimposing fast electronic pulse signals in a microwave resistive combiner. Although very fast switching is achievable, nonlinear behavior and circuits parasitic induce gain fluctuations and overshooting during the off-on process. Theoretical and experimental results show that the reduction of parasitics is an important parameter for improving the switching performance. The multipulse injection technique can improve the switching speed for a chosen degree of overshoot.

Optical amplitude modulation extinction by a deep saturated ultra-long semiconductor optical amplifier

The recovery of an optical carrier with the deletion of its amplitude modulation is introduced using a deeply saturated ultra-long semiconductor optical amplifier (UL-SOA). The experimental results were achieved for input signal bit rates up to 12.5 Gbps with high extinction ratio (up to 13.9 dB). The influence of parameters such as UL-SOA bias current, optical bandwidth, signal input power, modulation depth and bit rate are analyzed including the carrier spectral broadening effects due to the self-phase modulation effect.

Data rewriting after carrier erasing by ultra-long SOA

Optical carrier erasing is demonstrated with evaluation of further remodulation up to 12.5Gbps. Small impairments achieved for all but the 7G–7G and 12.5G–12.5G cases, when spurious-pattern noise force higher penalties (respectively 2.3dB and 0.7dB).

BER estimation from measured eye diagrams of a wavelength regenerative converter employing a single-SOA

Bit-error rate (BER) estimations are presented for an all-optical regenerator with wavelength conversion using just one semiconductor optical amplifier (SOA) by means of the cross gain modulation (XGM) in a counter-propagation mode. The extinction ratio (ER) degradation and the quality (Q) factor improvement obtained by the regenerator are analyzed, and good experimental performances were achieved. Others measured features of this regenerative converter are also presented.

Chip-on-carrier microwave mount for semiconductor optical amplifier measurements

The present paper describes a microwave mount (up to 40 GHz) with fiber facility inside an optical table for chip tests. Semiconductor optical amplifier (SOA) switching times of a chip-on-carrier (unpackaged) SOA were tested with rise times below 100 ps. It could be useful for a variety of SOA and photonic devices tests for electro-optical high-speed applications.

Equivalent circuit of a semiconductor optical amplifier chip with the bias current influence

Based on a diode-laser model, this paper presents the equivalent electrical circuit above and below the transparency condition for a chip (unpackaged) semiconductor optical amplifier. The modeling and parameters extraction were obtained as a function of the bias current, achieving good agreement between theoretical and experimental results in a wide frequency range, up to 40 GHz.

Wavelength conversion and 2R-regeneration using one semiconductor optical amplifier with cross-gain modulation compression

A simple all-optical wavelength conversion scheme with 2R-regeneration based on SOA is presented, exploring the cross-gain modulation (XGM) compression phenomenon and performing both the conversion and regeneration in one single device.

Frequency- and time-domain simulations of semiconductor optical amplifiers using equivalent circuit modeling

Abstract. We propose an equivalent circuit modeling for a chip-on-carrier and for two encapsulated semiconductor optical amplifiers (SOAs). The models include main parasitic leaks and were used in reflection and transmission simulations, showing good agreement with experimental data. The model for each SOA is validated, comparing the simulated results with experimental data from SOAs operating as high-speed electro-optical switches, reaching rise times below 200 ps.

Limits on High Bit Rate Wavelength Reuse Using Ultralong Semiconductor Optical Amplifier

Amplitude data erasure for wavelength reuse using an ultralong semiconductor optical amplifier (UL-SOA) in saturation is demonstrated for optical carriers modulated up to 56 Gb/s (NRZ). The erasing performance efficiencies with different input bit rates are presented, as well as the influences of parameters such as input (amplitude) extinction ratio, optical power, wavelength, and UL-SOA bias current. Bit error rate (BER) curves show that the remodulated (upstream) signal has enough quality to be applied in wavelength division multiplexing-passive optical networks (WDM-PON) systems, when very high bit rates or high input extinction ratio are needed and spectral broadening in the erased carrier could be accepted.