Contemporary and Future Trends in Optics - Optical Signal Processing by Silicon Photonics - page 16

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Pump Wavelength: 1554 nm

-25

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1500

Pump Wavelength: 1548 nm

Pump Wavelength: 1554 nm

1600 1700 1800 1900 2000 2100 1500 1600 1700 1800 1900 2000 2100 1500 1600 1700 1800 1900 2000 2100

converted wavelength [nm]

Fig. 2.3 Experimentally measured conversion efficiency as converted wavelength's function of
1,548, 1,554, and 1,560 nm (from left to right ) [ 7 ]

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Fig. 2.4 Sample showing four wave-mixing plot of converted signal light from 1,250 to
2,056 nm wavelength where 1,554.7 nm is the pump's wavelength with − 24 dB of on-off con-
version efficiency [ 7 ]

point and careful tuning of the pump wavelength allows for optimization of the
conversion bandwidth. The zero GVD point for this waveguide tracked at a wave-
length of 1,554 nm, and the dispersion slope is 1.9 ps/nm 2 km. The conversion
bandwidth is extended to 1,930 nm experimentally and then there is a consider-
able decrease for a short pump wavelength as shown in Fig. 2.3 left plot. In case
of a larger pump wavelength of 1,560 nm, the initial bandwidth converted experi-
mentally increased up to 1,760 nm only, the oscillatory features are really sharp as
demonstrated in the rightmost trace of Fig. 2.3 .
However, placing the pump at the zero GVD wavelength of 1,554 nm, the con-
version efficiency is maintained until 2,078 nm where we reach the tuning limit
of our signal laser (1,241 nm). The conversion efficiency over this bandwidth is
around − 18 dB and can be seen in the middle trace of Fig. 2.3 .
Figure 2.4 shows the wavelength conversion from 1,250 to 2,056 nm when the
pump is centered at 1,554.7 nm, the figure further demonstrates about − 24 dB