Semiconductor optical amplifier pattern effect suppression using Lyot filter

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

“…The format of the pulses is RZ so as to preserve the continuity with our previous relevant work [10][11][12][13], but also because this coding is preferable in terms of better receiver sensitivity and transmission performance compared to its NRZ on-off keying alternative [39,40], for which the nature of the pattern effect that has been addressed in [30] is less complicated [12,13]. Given now that in practice the quantity measured by the diagnostic equipment is the average power, P ave , it is necessary to define its relation to the peak power of the marks, P peak 1 , in order to be able to make the transition between experiment and theory in a straightforward manner.…”

“…Given now that in practice the quantity measured by the diagnostic equipment is the average power, P ave , it is necessary to define its relation to the peak power of the marks, P peak 1 , in order to be able to make the transition between experiment and theory in a straightforward manner. For a modulated pulse train, like the one generated according to the method described in [10][11][12], this is [41] P ave = P peak 1 (1 + 1/ζ)/2D, where ζ = P peak 1 /P peak 0 is the extinction ratio between the marks and spaces and D = T period /T FWHM is the duty factor. Thus by using Eq.…”

“…However, their efficiency in these applications is constrained by the pattern effect that occurs due to the strong saturation and incomplete recovery of their gain in between excitation pulses of random binary content [9]. Among the various methods we have recently proposed [10][11][12] to resolve this problem and enable the unobstructed exploitation of a stand-alone conventional SOA in its classical role, the use of an optical delay interferometer (ODI) with its appealing features [13] is a very promising option. This potential has been demonstrated both theoretically [13] and experimentally [12] for the case of return-to-zero (RZ) data format.…”

“…The ODI is serially placed after the SOA acting as a filter to properly suppress the spectral components of the unevenly amplified pulses that have been broadened under heavy saturation condition due to the manifestation of self-phase modulation (SPM), thus canceling the source of patterndependent distortion [14,15]. In this manner the amplitude wandering at the SOA exit, quantified by the amplitude modulation (AM), can be kept below an acceptable level [10][11][12][13]. This in turn allows the input power dynamic range of the SOA to be extended beyond the quasi-linear regime, where it should otherwise be operated for its gain to be unaffected by irregular variations at the expense of low output power and optical signal-to-noise ratio degradation [16,17].…”

Semiconductor optical amplifier pattern effect suppression for return-to-zero data using an optical delay interferometer

“…Therefore, the ODI is less sensitive to changes in the polarization state of the input signal as opposed to that of Ref. 12. Also, it is compatible with planar waveguide technology 14 and can be integrated with the SOA on a single chip, 16 so it is a more compact option than that of Ref.…”