Integrated Ammonia Sensor Using a Telecom Photonic Integrated Circuit and a Hollow Core Fiber

Andreas Hänsel,Anders Feilberg,Abubakar Isa Adamu,Christos Markos,Ole Bang,Martijn J.R Heck

doi:10.3390/photonics7040093

Andreas Hänsel, Anders Feilberg + Show 4 more

Open Access

https://doi.org/10.3390/photonics7040093

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Journal: Photonics	Publication Date: Oct 15, 2020
Citations: 2	License type: CC BY 4.0

Affiliation: Aarhus University, Technical University of Denmark

Abstract

We present a fully integrated optical ammonia sensor, based on a photonic integrated circuit (PIC) with a tunable laser source and a hollow-core fiber (HCF) as gas interaction cell. The PIC also contains a photodetector that can be used to record the absorption signal with the same device. The sensor targets an ammonia absorption line at 1522.45 nm, which can be reached with indium phosphide-based telecom compatible PICs. A 1.65-m long HCF is connected on both ends to a single-mode fiber (SMF) with a mechanical splice that allows filling and purging of the fiber within a few minutes. We show the detection of a 5% ammonia gas concentration, as a proof of principle of our sensor and we show the potential to even detect much lower concentrations. This work paves the way towards a low-cost, integrated and portable gas sensor with potential applications in environmental gas sensing.

Highlights

Gaseous emissions from intensive livestock production contribute to global warming and several other environmental challenges
This paper investigates the absorption lines within reach of telecom foundry processes, leveraging the high technological maturity of indium phosphide (InP) based diode lasers
The laser emission wavelength can be tuned by changing the driving current through the semiconductor optical amplifier (SOA), which was used for the fine tuning to sweep over the absorption line

Summary

Introduction

Gaseous emissions from intensive livestock production contribute to global warming and several other environmental challenges. A detailed discussion of PIC-based gas sensors regarding laser, interaction cell, and detector can be found in Reference [7] It is worth mentioning, that the proposed sensor can be adapted for different target gases, such as methane (CH4 ), carbon monoxide, carbon dioxide (CO2 ), acetylene, and hydrogen sulfide [6]. That the proposed sensor can be adapted for different target gases, such as methane (CH4 ), carbon monoxide, carbon dioxide (CO2 ), acetylene, and hydrogen sulfide [6] All of those gases have absorption lines within the possible emission ranges for telecom photonic integrated circuits. An even wider set of gases can be targeted when relying on other foundry processes that enable optical gas detection with PICs at wavelengths other than the telecom band [7]

Setup and Components

Results

Conclusions