tailieunhanh - Optoelectronics Devices and Applications Part 10

Tham khảo tài liệu 'optoelectronics devices and applications part 10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Part 4 Optical Switching Devices 17 Energy Efficient Semiconductor Optical Switch Liping Sun and Michel Savoie Communications Research Centre Canada 1. Introduction Energy-saving technology that reduces power consumption is of increasing importance due to the ever-increasing demand for Internet services. To prevent the traffic growth from being strangled by energy bottlenecks novel architectural and technological solutions are indispensable. The most obvious way to cope with the issue is to reduce the energy consumed by the network elements. Fast optical switching is an important enabler of advanced optical networks in particular such functions as routing burst and packet optical signals optical path provisioning and fault restoration. Semiconductor Digital Optical Switches DOSs can fulfill such high speed applications due to their nanosecond switching times step-like switching responses and immunity to variations in temperature wavelength polarization refractive index and device fabrication tolerances. Moreover semiconductor DOSs offer the potential for integration with other semiconductor optoelectronic components and thus promise considerable reductions in the size complexity and cost of an overall optical system. For optical waveguide switches fast optical switching may be achieved by a refractive index change induced either by carrier injection Zegaoui et al. 2009 Bennett et al. 1990 or by the electro-optic effect Cao et al. 2009 Agrawal et al. 1995 within III-V semiconductors such as GaAs-based and InP-based. Compared to carrier-injection switches electro-optic switches have faster switching speeds but larger switching voltages since the refractive index change induced by an electro-optic effect is about two orders of magnitude smaller than that by carrier injection. Therefore until now most of the commercially available semiconductor DOS products have been based on carrier-injection Ikezawa et al. 2008 . These devices typically utilize carrier-induced Total