Development of high-density single-mode polymer waveguides with low crosstalk for chip-to-chip optical interconnection

Abstract

High-density single-mode polymer waveguides were fabricated for chip-to-chip optical interconnection. The waveguides were designed as minimized mode field diameters for the lowest inter-channel crosstalk caused by mode coupling. The optimum relative index difference chosen was 1.2% to ensure compatibility with low crosstalk and wide fabrication tolerances. The 60-mm-length linear waveguides demonstrated a low propagation loss of 0.6 dB/cm and -45 dB crosstalk at 1310 nm. Also, a new crosstalk mechanism for a curved waveguide was revealed.

Femtosecond laser written waveguides deep inside silicon

“…Earlier work focused on optical logic; however, the greatest benefit of optical integration is expected to come from optical interconnects operating with low delay times and low power dissipation [2]. Such optical data transfer links are progressively finding use at shorter distances, providing advantages from high transmission rates enabled by wavelength division multiplexed operation over waveguides [3]. However, a major limitation in applying optical interconnects at short distances for chip-to-chip or potentially intra-chip connections is due to challenges in creating dense optical interconnects [4].…”

Optics in Computing: From Photonic Network-on-Chip to Chip-to-Chip Interconnects and Disintegrated Architectures

“…UC Davis demonstrated via gem5 simulations the significant execution time and energy savings accomplished over the electronic baseline [123], revealing also additional benefits when employing bitparallel transmission and flexible bandwidth-allocation techniques [125]. Experimental demonstrations of AWGRbased interconnection for compute node architectures were, however, constrained so far in the C-band regime, limiting their compatibility with electro-optic Printed Circuit Board (PCB) technology that typically offers a low waveguide loss figure at the O-band [126]. As such, AWGR-based experimental compute node interconnect findings were reported so far only in pNoC architectural approaches, using a rather small line-rate operation of 0.3 Gb/s [127].…”

O-Band Silicon Photonic Transmitters for Datacom and Computercom Interconnects

“…Nevertheless, O-band has turned lately into the dominant spectral regime at all levels of DC hierarchy, spanning from on-board level where ultra-low loss polymer waveguide technology [12] can enable chip-to-chip (C2C) interconnects, up to rack-scale [13] and long-reach transmission, where significant benefits arise from the zero-dispersion properties of standard single-mode fiber (SSMF) at 1300 nm [14]. Facing this reality, silicon photonic TX layouts have gradually started to migrate towards O-band operating modules, with recent demonstrations reporting single-channel RM TX devices with high line-rates of ≥60 Gb/s NRZ [15], [16] that can go beyond 100 Gb/s when employing advanced PAM4 modulation [15]- [17] and several RM-based WDM TX demonstrations having already been reported to reach up to 25 Gb/s line rate capabilities [4], [18], [19].…”