Conclusions

In this chapter, we conduct static and dynamic characterization of a integrated MZI-SOA. All active and passive components of the MZI-SOA were characterize to assess the properties of the device for phase modulation experiments. This process allow extracting the coupling factors and relevant gain functions which contribute for the determination of the MZI-SOA behavior, having in mind that most of these parameters are hidden, since they are masked in the output power which are normally a sum or difference of internal fields with amplitude and phase variations.

A novel method to perform optical phase modulation has been presented, based on an all-optical XOR gate configuration. We assess the impact of SOAs bias current and input CW power on the phase of the destructive output of a MZI-SOA. We observed that an increase of the bias current produces higher values of phase spans and output mean powers. However, SOAs gain saturation has an opposite effect on the output signal. The experimental results demonstrate the feasibility of a MZI-SOA device as an optical phase modulator.

Summarizing, having in mind next generation optical networks, which are meant to be as flexible and transparent as possible, this chapter has characterized the operating conditions of the MZI-SOA working as an optical gate and phase modulator, which results will be useful for the next chapters, dealing with advanced modulation format conversion techniques.

References

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Chapter 4

MZI-SOA Static Model

4.1 Introduction

T

However, integrated MZI-SOAs with hybrid technology encompasses several components (couplers, waveguides, phase shifters and SOAs), all with their own tolerances and asymmetries. These issues lead to very long and difficult initial setup phase [1], which varies from device to device due to fabrication and integration yields. However, MZI-SOA working characteristics are well described with a static model, through which we can carry out the operational parameters optimization and the determination of operational limits.

This chapter starts with the description of a static model of a MZI-SOA, based on the interferometric structure of the MZI, and power measurements following the procedure described in the previous Chapter (See section 3.1 for more details). MOGA is exploited for operational parameter extraction of the model.