Optical switch compatible with wavelength division multiplexing and mode division multiplexing for photonic networks-on-chip

Abstract

We propose a 2 × 2 multimode optical switch, which is composed of two mode de-multiplexers, n 2 × 2 single-mode optical switches where n is the number of the supported spatial modes, and two mode multiplexers. As a proof of concept, asymmetric directional couplers are employed to construct the mode multiplexers and de-multiplexers, balanced Mach-Zehnder interferometer is utilized to construct the 2 × 2 single-mode optical switches. The fabricated silicon 2 × 2 multimode optical switch has a broad optical bandwidth and can support four spatial modes. The link-crosstalk for all four modes is smaller than -18.8 dB. The inter-mode crosstalk for the same optical link is less than -22.1 dB. 40 Gbps data transmission is performed for all spatial modes and all optical links. The power penalties for the error-free switching (BER<10) at 25 Gbps are less than 1.8 dB for all channels at the wavelength of 1550 nm. The power consumption of the device is 117.9 mW in the "cross" state and 116.2 mW in the "bar" state. The switching time is about 21 μs. This work enables large-capacity multimode photonic networks-on-chip.

Nonvolatile and ultra-low-loss reconfigurable mode (De)multiplexer/switch using triple-waveguide coupler with Ge2Sb2Se4Te1 phase change material

“…The IL ON is lower than 1.0 dB over 80 nm from 1520 nm to 1600 nm and the 1dB-IL OFF bandwidth is over 60 nm from 1520 nm to 1580 nm. Compared to the MZIs based RMDS, the IL is significantly decreased from several dB to less than 1.0 dB 9 . Compared to the micro-rings based RMDS, the bandwidth is dramatically increased from a narrow bandwidth of only < 13 GHz to 100 nm 10 .…”

“…The CTs at “OFF” and “ON” states are −19.08 dB and −22.86 dB, respectively. The total coupling length of the optimised RMDS is L OFF + L ON = 29.3 μm, which is an ultra-compact size compared with that of the MZIs based ones (~several hundreds of micrometers) 9 . We need to pay attention to Fig.…”

“…Only a few RMDSes have been reported based on the Mach–Zehnder interferometers (MZIs) 9 , micro-ring resonators 10 , and multimode interference (MMI) structures with phase shifters 11 . One approach could be the use of the MZIs with phase shifters.…”

“…One approach could be the use of the MZIs with phase shifters. A 2 × 2 multimode optical switch was experimentally achieved with a link-crosstalk for all four modes of <−18.8 dB, composed of two mode DeMUXs, n 2 × 2 SM optical switches and two mode MUXs 9 . This reported approach is based on the independent processing of the single modes’ signals using SM switches, in which the input multimode signals are firstly all converted into the fundamental mode (mode-conversion process); and then, the optical signals are switched by processing of individual channels using conventional optical switches (mode-switching process); finally, the SM signals are reconverted into their original higher-order modes at the output ports (mode-reconversion process).…”

Silicon chip-scale space-division multiplexing: from devices to system

“…A 2×2 mode-selective switch is more efficient than a 1×2 case, because it can manipulate two optical links. Jia et al [125] realized a 2×2 mode-selective switch that supported four-mode channels. For the abovementioned multi-port mode-selective switches, the signals were all demultiplexed to FMs and then handled individually using single-mode elements.…”