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All optical switches have been used with measured success in response to a high demand in all optical networks, and a
dramatic increase in the Internet and communication needs over the last decade. The wavelength-selective switch is the
mechanism used in various switching applications. MEMS-based wavelength-selective switches (WSS) are the most
promising technology to bring all-optical switches into wide implementation by providing reasonable cost, excellent
performance, and most reliable use of micro-electromechanical systems (MEMS) technology. Optical-MEMS devices,
often referred to as micro-opto-electromechanical systems or MOEMS; have been used successfully in optical network
systems and particularly in switching devices such as waveguide and free-space switches. Free-space switching devices
are more popular than waveguide switches, because they offer faster switching time and are more scalable. 1D MEMS-based
WSSs, using free-space approach, require the use of integrated multiplexer/de-multiplexer and micro-mirror arrays
for their operations [1, 2]. The switching time depends primarily on the time it takes for the scanning micro-mirrors to
steer de-multiplexed beams to the desired output ports. This is due to the fact that the mirrors are the main inertial
components in free-space switching systems. Grating Light Modulators (GLM) were introduced a decade ago for use in
diffraction optics. Research has begun to investigate their use in communication optics. Unlike other 1D MEMS-based
WSS, GLM promises to offer very low loss for the whole system and fast switching time of as low as 20 ns with no
integrated micro-mirrors [3-5]. We propose the development of a switching system incorporating a GLM as the central
unit acting as both de-multiplexer and switching device in one spot, and which does not require any moving micro-mirror
arrays. Therefore, the switching time is entirely dependent on the GLM device which is relatively fast. GLMs use
diffraction principles to de-multiplex a WDM signal with a square-well grating-like deformation when suitable voltages
are applied to the device to perform switching between 'ON' and 'OFF' states. We review the fundamental of GLM and
its operation and showcase our proposed configuration that will confirm the promise that GLMs hold for future
wavelength switching applications.
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