Ultra-small, self-holding, optical gate switch using Ge_2Sb_2Te_5 with a multi-mode Si waveguide

Abstract

We report a multi-mode interference-based optical gate switch using a Ge(2)Sb(2)Te(5) thin film with a diameter of only 1 µm. The switching operation was demonstrated by laser pulse irradiation. This switch had a very wide operating wavelength range of 100 nm at around 1575 nm, with an average extinction ratio of 12.6 dB. Repetitive switching over 2,000 irradiation cycles was also successfully demonstrated. In addition, self-holding characteristics were confirmed by observing the dynamic responses, and the rise and fall times were 130 ns and 400 ns, respectively.

Simulations of Silicon-on-Insulator Channel-Waveguide Electrooptical 2 × 2 Switches and 1 × 1 Modulators Using a ${\bf Ge_2}{\bf Sb_2}{\bf Te_5}$ Self-Holding Layer

“…Because of multi-micron travel in the film plane, the guided mode here "senses" the GST complex index and responds to changes in index. Experiments in the literature [2], [3] have placed GST upon an exposed surface of a waveguide where this GST layer acts as optical cladding so as to effect the relatively weak "fringing field" of the guided mode [6], [7]. Those papers demonstrated modulation and switching by means of a "pumping" light beam incident upon the cladding.…”

“…optically by an external 700-nm light beam [2]- [4]. We, however, consider electrical control to be more suitable for practical applications than the optical actuation.…”

Amplitude trimming of Si waveguides using phase change material

“…We have previously reported optical switches using phase change material (PCM) [10,11,12,13], and we have proposed a phase and an amplitude trimming method for Si optical devices utilizing PCM [14]. PCM has two stable states at room temperature, amorphous and crystalline.…”

Ultra-compact, self-holding asymmetric Mach-Zehnder interferometer switch using Ge₂Sb₂Te₅ phase-change material

“…In particular, self-holding characteristics are necessary for energy efficient routing nodes. Previously, we proposed optical switches using phasechange material (PCM) [1,2,3,4,5,6] that were suitable for such applications. PCM has two stable states at around room temperature, an amorphous state and a crystalline state [7].…”

“…In addition, the switching time is less than 400 ns, which is much shorter than that of thermo-optic switches. With the PCM switch we achieved stable repetitive switching over 2000 times [3]. In this letter, we describe the fabrication of an asymmetric Mach-Zehnder interferometer (MZI) optical switch using Ge 2 Sb 2 Te 5 and report on a demonstration of the switching operation by laser pulse irradiation onto smallarea Ge 2 Sb 2 Te 5 films on the Si waveguides.…”