Dr. Hani Nejadriahi is a postdoctoral fellow at JPL’s Microdevices Laboratory, where she does research and development of integrated-photonic technologies for space applications.

Hani’s work focuses on design, modeling, fabrication, and characterization of passive and active photonic integrated circuits (PICs) in novel materials such as ultra-low loss silicon nitride and gallium nitride that she develops in-house.

Silicon nitride (Si3N4) due to its broad transparency window which extends from UV to NIR (200 to ~2500 nm), low losses (~ <10 dB/m), high optical power handling (due to negligible TPA), thermal stability, customizability and integration capabilities plays a crucial role in the development of laser optics systems for cold atom sensors and applications.

In particular as part of current efforts at MDL towards the laser optics improvements and miniaturization of cold atom sensors, after realizing a ~ 1dB/m loss Si3N4 platform at 780-852 nm, Hani has focused on development of ultra-narrow linewidth external cavity lasers around these wavelengths since commercial lasers are either not available at these wavelengths or are not narrow-linewidth enough. Hence bringing this technology to MDL/JPL is of utmost importance for many applications that benefit from having integrated narrow linewidth lasers.

Additionally, to build a fully working system on-chip, more devices are currently under development by her such as wavemeter, phase modulator/switches, isolators, and passive components such as splitters, couplers and interferometers.

On the other hand, Gallium nitride is a well-established compound semiconductor with many advantages in different functionalities and application due to its piezoelectricity, transparency around UV and visible wavelengths (good coverage around 780-852nm), and the ability to confine acousto-optical interaction with efficient device designs via lithographic control at wavelength scales. Hani actively is working under the Advanced Component Technology (ACT) program where she designs, fabricates, and characterizes acousto-optic devices in GaN-on-Sapphire to achieve high performance acousto-optic modulator (AOM) with mW-level drive powers.

These waveguide platforms enable low SWaP and reliable next generation of devices and systems of interest to many NASA applications spanning from Earth Sciences (i.e., cold atom sensors) to astrophotonics (for coronographs, wavefront correction, and spectrographs). These PICs are wavelength agnostics and can operate at any wavelength depending on the bandgap of the material they are designed in and are a fertile ground to explore new type flight compatible systems.

In addition to her integrated photonics work, Hani works on design and fabrication of diffractive optical elements using both binary and greyscale lithography (i.e., gratings for spectrometers, lenses, etc). Many of these components are essential part of many flight projects at JPL.