High-Efficiency Ultra-Broadband Multi-Tip Edge Couplers for Integration of Distributed Feedback Laser With Silicon-on-Insulator Waveguide

Abstract

A high-efficiency ultra-broadband multi-tip edge coupler based on a silicon-oninsulator platform for direct coupling with the elliptic beam of a distributed feedback laser was developed. The device is composed of a multi-tip section and a combiner section with extra offset regions to reduce the mode mismatch caused by the structural discontinuity which results from a limitation of the fabrication process that creates an inevitable gap width at the junction between the two sections. The widths and the spacing of the tips for the multi-tip section and the extra offset region for the combiner section are fine-tuned by using the particle swarm optimization method to reduce the mode mismatch. A high overall coupling efficiency up to 90.68% (0.4249 dB) at 1550 nm can be achieved for the optimized 90-μm-long four-tip edge coupler. The device can be operated over a broad spectral range of 1260-1675 nm with less than 1 dB extra loss. With its high-efficiency ultra-broadband operation and small device footprint, the proposed device is promising for laser-to-chip edge coupling in silicon photonics.

Edge Couplers in Silicon Photonic Integrated Circuits: A Review

“…The utilization of multiple tips can introduce a high degree of design freedom to realize the expected coupling efficiency within a notably small footprint. The total length of a multi-tip taper is usually below 100 µm [59,60]. As depicted in [60], an edge coupler on the basis of double-tip inverse tapers is designed, fabricated, and characterized.…”

“…On this basis, a multi-tip taper is commonly prepared via electron beam lithography (EBL) patterning, which is highly precise and convenient with a single-step process at the expense of being time-consuming and expensive. In addition to general applications in fiber-to-chip optical coupling, multi-tip tapers with flexible tip width and tip numbers can also work under chip-to-chip communication [56] or laser-to-chip optical interconnect [59].…”

Design of Silicon Nitride Edge Coupler for Monolithically Integrated Laser on Silicon Photonic Circuits With Relaxed Alignment Tolerance and High Efficiency

“…Thus, we can build a bi-layer coupler to expand the mode area easily in both x-and y-direction. If only one 220-nm-thick Si layer is used [8]- [10], the mode area cannot be expanded effectively in the y-direction. The other difference is that we choose a specially designed monolithic laser.…”

“…To our knowledge, this method has so far not been fully investigated for laser-to-chip monolithic coupling. Recent publications demonstrated the integration of a laser die through a Si EC and the reported insertion loss was around 2 dB [8]- [10].…”

CrossLight: A Cross-Layer Optimized Silicon Photonic Neural Network Accelerator

“…Table II shows the optoelectronic parameters considered for this simulation-based analysis. We considered photonic signal losses due to various factors: signal propagation (1 dB/cm [6]), splitter loss (0.13 dB [27]), combiner loss (0.9 dB [28]), MR through loss (0.02 dB [29]), MR modulation loss (0.72 dB [30]), microdisk loss (1.22 dB [31]), EO tuning loss (6 dB/cm [20]), and TO tuning loss (1 dB/cm [17]). We also considered the 1-to-56-Gb/s ADC/DAC-based transceivers from recent work [37].…”