Contemporary and Future Trends in Optics - Optical Signal Processing by Silicon Photonics - page 15

4

back-to-back (D1)

back-to-back (D2)

back-to-back (D3)
back-to-back (D4)
converted (D1)
converted (D2)
converted (D3)
converted (D4)

6

8

12

14

14

-15 -12 -9 -6 -3

Received power (dBm)

Fig. 2.2 The BER curve of 40 Gb/s shown on each output of the demultiplexer (D1-D4) [ 7 ]

Figure 2.2 shows BER curves of the converted signal at the rate of 40 Gb/s for
each output of the four de-multiplexer (D1-D4). After the modulation the back-
to-back curve is taken directly (no amplifiers, chips or filters in the optical path-
way) of a probe signal which is set to the same wavelength as that of the signal
which is converted. They described the high-speed longest-spanning wavelength
conversion reportedly lie in a dispersion engineered silicon photonic waveguide,
and have characterized the BER degradation quantitatively produced as a result
from the conversion.
The degradation cause is determined primarily and it is found to be due to the
conversion efficiencies which are limited, but in near future some improvements
are really expected in active devices. Thus, the results provide advancement sig-
nificantly toward the ultrafast all-optical parametric processing devices integration
within large-scale optical networking systems.
Turner-Foster et al. [ 7 ] demonstrated ultra-broadband low-peak-power fre-
quency conversion of CW light in a silicon photonic structure via four-wave mix-
ing. The process produces continuous conversion over two-thirds of an octave
from 1,241- to 2,078-nm wavelength light. Also investigate FWM in silicon wave-
guides with the zero GVD (group-velocity dispersion), point near the center of the
C-band where high power pump lasers are readily available. This design is criti-
cal to enable efficient broadband parametric conversion. Pumping near this zero
GVD point and observed extremely broad conversion bandwidth with over 830 nm
allowing for conversion from 1,241 to 2,078 nm continuously.
The signal and pump are launched into the waveguide's TE-like mode all the
way through the inverse nano-taper. Signal is then scanned from 1,241 nm to the C
band's pump wavelength. The average power of the signal and pump are 110 and
1.1 mW respectively, in the waveguide. The bandwidth of conversion very much
rely on the pump wavelength location with respect to the waveguide's zero GVD