The method for constructing fault-tolerant photonic switches for high-performance computing systems

In this paper the new type of fault-tolerant non-blocking photonic switch is presented for the first time. The proposed switch architecture is based on quasi-complete graph topology which use provides non-blocking and fault-tolerant switching process. The new two-stage switch architecture uses the stage of dual photonic switches and pairs of photonic demultiplexers and multiplexers which have been described in detail by authors in their previous works. Depending on the number of different backup connections, the two types of fault-tolerant pho-tonic switches are considered in this paper: single-channel fault-tolerant photonic switch and dual-channel fault-tolerant photonic switch. The mathematical expressions for calculating the switching and fiber complexities of these two types of fault-tolerant photonic switches are also presented here for the first time. The numerical calculations shown that the increasing the reliability of the fault-tolerant photonic switches twice leads to an increasing their switching complexity in 1.4 times and fiber complexity in 1.8 times.

Reduction in Crosstalk Using Uniform Germanium Strips for Dense Integration of Photonic Waveguides

The requirement of low crosstalk between the neighboring waveguides should be considered essentially, in order to achieve the compact photonic integrated circuit (PIC), which includes photonic waveguides. Literature shows that the lower crosstalk can be realized by using the silicon-on-insulator (SOI) based waveguide, having an appropriate separation between them. The current work is focused on reducing the waveguide separation to further improve the photonic integration over the PICs. This has been achieved by inserting the germanium strips between the photonic waveguides. The investigations of the impact of variations in heights and widths of germanium strip have demonstrated that the crosstalk can be reduced by a significant amount, which provides noteworthy improvement in coupling length. The maximum coupling lengths of 81578 µm, 67099 µm, and 66810 µm have been achieved at their respective end-to-end separations of 300 nm, 250 nm, and 200 nm, and their corresponding minimum crosstalk values have been noted as -29.40 dB, -27.71 dB, and − 27.70 dB. Moreover, the analysis to realize the coupling length for Ge-strip, have been compared with the Si-, and SiN-strips. The approach presented in the current work can be utilized for the design of many compact photonic applications, such as polarization splitter, integrated photonic switches, etc.

A Review of Devices for Integrated Silicon Photonic Switches

In this paper, we review devices used in silicon photonic switches. Devices in switches are divided into active and passive devices. Active devices consist of microring resonator, contra directional couplers, mach zhender switches. Passive devices consist of waveguide crossings and arrayed waveguide gratings. We also list the state of the art in devices in a comparison table.