Silicon Nitride

Overview

Silicon Nitride (SiN) strengths lie in its low loss and broad transparency range. Where SOI fails to perform, silicon nitride steps in. CMOS compatible, SiN offers some remarkable advantages in performance and has great compatibility with visible light down to about 400 nm.

Characteristics

Silicon nitride is considered a passive platform, meaning that it has no light generating capability, modulators, or detectors directly available. It requires either hybrid or heterogeneous integration with other active components such as amplifiers, photodetectors and lasers for light emission, amplification or detection.

Thanks to its transparency window, light with wavelengths below 1000nm can be used even extending into the visible range down to just above 400nm. This makes SiN one of the platforms with the broadest wavelength coverage and a versatile platform, typically consisting of a single or double slab of SiN with silica (SiO2) as a cladding layer. This cladding can be locally removed to form windows for sensing or add other materials.

A key feature of SiN is its very low propagation loss, which is crucial for many quantum applications. Compared to SOI, SiN can also guide higher laser powers, exceeding 100mW and sometimes even reaching the Watt power level.

Without integrated active components, switching speeds are limited to the kHz range using thermo-optical phase shifters.

With integration of piezo-actuators, speeds of a few hundred MHz can be achieved, and with lithium niobate, up to 10s of GHz can be reached.

Applications

With its broad wavelength coverage, SiN is used beyond data- and telecom, particularly for applications operating in the visible spectrum, such as medical applications including biosensing and quantum applications . Its low losses make it ideal for metrology applications, sometimes in combination with hybrid integrated lasers due to their narrow linewidths.

Bring your PIC project to life

At Epiphany Design, we work with all PIC material platforms and always advise our customers on the best choice for their particular applications. When it comes to silicon nitride photonics, we know how to make the most of its strengths to create solutions across a wide range of use-cases. We specialize in PIC Design, but also provide support at all stages of PIC development when needed.