Analysis of bit rate dependence up to 80Gbit/s of a simple wavelength converter based on XPM in a SOA and a shifted filtering

Abstract

This paper provides the analysis of wavelength converted pulses obtained with a simple semiconductor optical amplifier (SOA)-based wavelength conversion scheme, which exploits cross phase modulation (XPM) in an SOA in conjunction with shifted filtering. The analysis includes experimental measurements of the back-to-back system performances as well as frequency-resolved optical gating (FROG) characterisations of the wavelength converted pulses. These measurements are implemented at different bit rates up to 80 Gbit/s and for both red and blue shifted filtering, particularly showing different patterning effect dependences of red and blue shifting techniques. This analysis is developed by the addition of a numerical study which corroborates the experimental results. A further understanding of the different performances of red and blue filtering techniques, presented in the literature, can thus be proposed.The placement of the filter to undertake red shifted filtering (RSF) allows us to achieve very short pulse widths but high bit rate operation is limited by pattern effects. The blue shifted filtering (BSF) technique shows optimum performance as regards to patterning effects even if the wavelength converted pulses can be larger . 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 thus be proposed. The placement of the filter to undertake red shifted filtering (RSF) allows us to achieve very short pulse widths but high bit rate operation is limited by pattern effects.

On the compensation of chirp induced from semiconductor optical amplifier on RZ data using optical delay interferometer

“…This is negative in the leading edge (red chirp) of the pulse, almost linear with increasing slope in its central part and positive in its trailing edge (blue chirp). The red chirp is related to carrier depletion and gain compression while the blue chirp is linked to carrier regeneration and gain recovery [24]. Since in Fig.…”

“…The idea of using an optical filter, which the ODI essentially is, directly after an SOA to properly engineer the chirp imposed on the pulses passing through, has been undertaken before. However this has been done in various applications of SOA-based switches whose operation relies on the change of the SOA response incurred by one signal and suffered by another [23][24][25][26][27][28][29]. On the contrary in our case the modification of the SOA gain dynamics is provoked by a data-modulated signal onto itself, and so the approach required for removing patterning is different from a physical perspective.…”