One of pictures of the oscillations E 1L (t, h, y, x) and E 2L (t, h, y, x) adding result in
the far zone is presented in Fig. 7.15. Here functions of the module |E SLN00 (h, y)|
2
and the contour lines calculated from Eqs. (7.26–7.30) are presented for symmetric
waveguides (Fig. 7.15 a, b) and nonsymmetric waveguides (Fig. 7.15 c, d) of the
first and second optical channels Ch1, Ch2.
From Fig. 7.15 we see that the symmetry disturbance in the optical channels Ch1,
Ch2 leads to the main maximum offset (Fig. 7.15c, d); the side components from the
right side from the main maximum increase by several times. At oscillations E 1L (t,
h, y, x) and E 2L (t, h, y, x) adding in out-of-phase or in “non-quadrature” mode
(Fig. 7.15e–g) for the case of nonsymmetric adding (Fig. 7.15g), the interference
rings undergo the strong distortions with the nonuniform intensity redistribution
over the perimeter of interference rings.
7.2.8 OEO as the Correlator with Utilization of Spatial
Filtering
The structure of OEO MZ presented in Fig. 7.5 contains the spatial filter SF, which is
intended for suppression improvement of the DC component of the optical carrier.
Application of spatial filters in OEO for improvement of the oscillations’ quality is
the promising direction in OEO investigations. In this case, we use methods of
adaptive optics, Fourier transforms, and the spatial correlation analysis.
The OEO MZ structure presented in Fig. 7.5 can be considered as the coherent
optical processor [8] or as the spatial correlator with utilization of spatial filtering. In
OEO, we can perform the convolution operations not only in optical and RF ranges,
but the spectra convolution operation over spatial frequencies. As the spatial filters,
we can use the miniature circular and sector spatial filters, which are well studied in
publications on the Fourier optics.
In the perspective, we may think about researches on a suppression of the DC
component of laser emission in OEO, on equalization of the optical phase in the
transverse section, on correction of the image symmetry on the PD area with
utilization of the nanotechnology innovations. On the one hand, the further investigations are required for new methods of spatial filtering of QWLD emission in OEO
MZ (Fig. 7.5) for improvement of PSD of the phase noise. On the other hand, OEO is
used as a device for the spatial correlation analysis of objects with application of
matched filtering at the RF exact indication.
7.2 The Model of the Dielectric Waveguide Structure of the Laser and the Optical. . .
391
the far zone is presented in Fig. 7.15. Here functions of the module |E SLN00 (h, y)|
2
and the contour lines calculated from Eqs. (7.26–7.30) are presented for symmetric
waveguides (Fig. 7.15 a, b) and nonsymmetric waveguides (Fig. 7.15 c, d) of the
first and second optical channels Ch1, Ch2.
From Fig. 7.15 we see that the symmetry disturbance in the optical channels Ch1,
Ch2 leads to the main maximum offset (Fig. 7.15c, d); the side components from the
right side from the main maximum increase by several times. At oscillations E 1L (t,
h, y, x) and E 2L (t, h, y, x) adding in out-of-phase or in “non-quadrature” mode
(Fig. 7.15e–g) for the case of nonsymmetric adding (Fig. 7.15g), the interference
rings undergo the strong distortions with the nonuniform intensity redistribution
over the perimeter of interference rings.
7.2.8 OEO as the Correlator with Utilization of Spatial
Filtering
The structure of OEO MZ presented in Fig. 7.5 contains the spatial filter SF, which is
intended for suppression improvement of the DC component of the optical carrier.
Application of spatial filters in OEO for improvement of the oscillations’ quality is
the promising direction in OEO investigations. In this case, we use methods of
adaptive optics, Fourier transforms, and the spatial correlation analysis.
The OEO MZ structure presented in Fig. 7.5 can be considered as the coherent
optical processor [8] or as the spatial correlator with utilization of spatial filtering. In
OEO, we can perform the convolution operations not only in optical and RF ranges,
but the spectra convolution operation over spatial frequencies. As the spatial filters,
we can use the miniature circular and sector spatial filters, which are well studied in
publications on the Fourier optics.
In the perspective, we may think about researches on a suppression of the DC
component of laser emission in OEO, on equalization of the optical phase in the
transverse section, on correction of the image symmetry on the PD area with
utilization of the nanotechnology innovations. On the one hand, the further investigations are required for new methods of spatial filtering of QWLD emission in OEO
MZ (Fig. 7.5) for improvement of PSD of the phase noise. On the other hand, OEO is
used as a device for the spatial correlation analysis of objects with application of
matched filtering at the RF exact indication.
7.2 The Model of the Dielectric Waveguide Structure of the Laser and the Optical. . .
391