Adiabatic mode converters for silicon photonics: Power and polarization broadband manipulators

Argishti Melikyan,Po Dong

doi:10.1063/1.5080247

Abstract

Highlights

Silicon photonic (SiPh) circuits have recently been demonstrated for applications wherein the operating wavelength range extends beyond the traditional communication C-band
SiPh technology has been demonstrated to be advantageous in applications such as O, E, S, C, and L band coherent communication,4 optical coherence tomography (OCT),3 sensing,5,6 quantum computing,1 and photonic neural network
Silicon photonic passives such as a 3 dB power splitter/combiner with flat wavelength response across the 85 nm measurement wavelength range are reported for both quasi-TM and quasi-TE polarizations

Summary

INTRODUCTION

Silicon photonic (SiPh) circuits have recently been demonstrated for applications wherein the operating wavelength range extends beyond the traditional communication C-band. SiPh technology has been demonstrated to be advantageous in applications such as O, E, S, C, and L band coherent communication, optical coherence tomography (OCT), sensing, quantum computing, and photonic neural network. The level of circuit complexity that silicon photonics will most likely endow requires on-chip manipulation of the power and the polarization in a broad wavelength range. broadband and low-loss passive devices such as 3 dB power splitters/combiners for quasiTE and quasi-TM polarized lights, power tappers, polarization beam splitters (PBS), and polarization rotator splitters (PRS) are going to be crucial. The bandwidth of direction couplers has been improved by designing more complex structures with multiple coupled sections or bent waveguides designs.14–17 These device show excellent wavelength response and low losses, they tend to require tight fabrication. To reduce the probability of non-adiabatic transitions and to increase the operating wavelength range, these devices are usually rather bulky with lengths of around 1 mm.27 Despite of their large dimensions, the adiabatic mode converters remain as the most promising devices for realizing low loss and broadband optical passives because of their simple designs. We use a simple method to optimize the waveguide shapes along the propagation direction Silicon photonic passives such as a 3 dB power splitter/combiner with flat wavelength response across the 85 nm measurement wavelength range are reported for both quasi-TM and quasi-TE polarizations. All the adiabatic mode converters discussed in the paper are tested for their operation in a wavelength range of 1520–1620 nm

Design methods

MEASUREMENT DATA

Power splitter and combiners

Polarization manipulators