Advancements in Silicon Photonics - Optical Signal Processing by Silicon Photonics - page 32

application industries of silicon photonics. The speed of technological improve-
ments is so fast that a new type of Moore's law is needed in silicon photonics
industry.
SOI based novel technology enables fabrication of low loss waveguides, high-
quality resonators, high speed modulators, efficient couplers, photo-detectors, and
optically pumped lasers. Developing efficient detectors and lasers for telecom
wavelengths at low-cost are the two main technological hurdles before silicon can
become a broad platform for integrated optics. The future of silicon photonics lies
mainly in producing very low loss waveguides, integrated designs, spot-sized low
loss (less than 0.1 dB) converters, reduced-bend size of resonators, and highly
efficient interconnections. The further advancement in photonics industry will be
the polarization-independent nature of these devices and overcoming the thermal
constraints.
The losses can be reduced by eliminating rough side wall surfaces and care-
ful selection of the waveguide geometries with wavelength selection. Two-
photon absorption can potentially be used to avoid the limits and building a
better silicon light detection devices on the chip. The fields which are to be con-
centrated more in future are level of integration, control signaling, and packag-
ing structures. The greater functionality with lower cost can be achieved if the
CMOS foundries concentrate more and come up with new design techniques of
integration.
4.1 Silicon-on-Insulator Waveguides and Coupling Devices
Silicon on Insulator (SOI) waveguides are attracting considerable attention in
recent years, and the devices based on these optical waveguides are impor-
tant to realize many modern all-optical signal processing systems. The main
driving forces behind these devices are the technological improvements in
exploiting the nonlinear optical phenomenon and their compatibility with
CMOS devices. Although all-optical signal processing devices have been
investigated intensively, the chip-scale solution provided by the silicon pho-
tonics is the most promising one. Silicon photonic devices are finding their
applications not only in telecommunication transmission systems and biomed-
ical instruments, but also in the new generation of high performance comput-
ing system.
In recent years, silicon waveguides have shown numerous nonlinear optical
applications in various areas particularly in communication. The considerable
attention toward the silicon photonics keeps an aim to produce cost-effective opti-
cal signal processing devices that can integrate with the present electronics on
chip-scale dimensions, as well as can meet the near future demand of more than 1
terabit/s rate. This demand of much increased bandwidth will certainly be unbear-
able by copper links.