A Reconfigurable Multimode Demultiplexer/Switch for Mode-Multiplexed Silicon Photonics Interconnects

Abstract

We experimentally demonstrate a scalable and broadband reconfigurable multimode demultiplexer/switch (RMDS) for mode-division multiplexed inter-and intra-chip data communication systems. The RMDS exploits a thermo-optically tuned tapered multimode interference coupler, enabling simultaneous transmission of the fundamental and first order quasi transverse electric modes in C-band. It is used as the building block in a mode demultiplexer with −20 dB crosstalk, which can be reconfigured as a mode selecting switch with 10.9 µs switching time. An aggregated bandwidth of 2 × 10 Gb/s is achieved by the parallel transmission of two nonreturn-to-Zero (NRZ) PRBS31 data signals at 10 −12 biterror-rate with 2.8 dB BER power penalty. A 1.55 pJ/bit energy efficiency is estimated for a proposed multimode optical link.

Reconfigurable and Scalable Multimode Silicon Photonics Switch for Energy-Efficient Mode-Division-Multiplexing Systems

“…The multiplexed mixed-mode signal propagates through the multimode waveguide and coupled to the input port of MMI-A, which is a reconfigurable multimode demultiplexer/switch (RMDS); designed using the mechanism of symmetric interference. We proposed and tested this novel silicon photonics component, consisting of a 72 μm long 1 × 3 MMI coupler, in [19] for the (de)multiplexing of two parallel high-speed data channels over two simultaneously transmitted TE modes (TE0+TE1). The input port of the MMI-A has a 2.9 μm wide and 20 μm long taper for the multimode transmission to adiabatically couple TE0, TE1 and TE2 modes to the MMI-A.…”

“…The estimated crosstalk is less than −29.0 dB in all cases. The operation principle of the dual-mode (TE0+TE1-in) transmission is reported in [19].…”

“…The operation principle and experimental demonstration of simultaneous dual-mode transmission in an MMI based mode (de)multiplexer is reported in [19]. For the reconfigurable switching of two simultaneous TE modes (TE0+TE1-in), the PS-1 phase shifter is optimized so that the combined light beam of the TE1-in mode components always appear in the middle output port of MMI-B ( Fig.…”

“…4(c)) can provide <−20 dB crosstalk over a large wavelength range (1520 nm -1580 nm) for individual-mode switching, the operating range reduces below 12 nm for the dual-mode transmission with a large (>−10 dB) crosstalk. However, the MMI based mode multiplexer, as in [19], provides broadband response and sufficient crosstalk for simultaneous 2-mode switching. For this reason, the dual-mode (TE0+TE1-in) characterization is done using a MMI based mode multiplexer followed by the SMS of Fig.…”

Multilayered Maxwell’s fisheye lens as waveguide crossing

“…New methods supporting the crossing of multiple waveguides based on inverse-design [12] and the MFE lens [13] have been investigated. Multimode waveguides play an important role in PICs and variety of devices are proposed based on them such as optical filters [14][15][16], power splitters [17,18], polarization splitters [19,20], sensors [21,22], (de)multiplexers [23][24][25][26], switches [27][28][29], and wavelength converter [30]. Therefore, designing multimode waveguide crossings is vital in PICs and they have been introduced based on multimode-interference couplers [31,32], subwavelength asymmetric Y-junction [33], and the MFE lens [34].…”