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Dal Cin S, Windischhofer A, Pilat F, Leskowschek M, Pecile VF, David M, Beiser M, Weih R, Koeth J, Marschick G, Hinkov B, Strasser G, Heckl OH, Schwarz B. An interband cascade laser based heterodyne detector with integrated optical amplifier and local oscillator. NANOPHOTONICS 2024; 13:1759-1764. [PMID: 38681676 PMCID: PMC11052533 DOI: 10.1515/nanoph-2023-0762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 01/24/2024] [Indexed: 05/01/2024]
Abstract
Heterodyne detection based on interband cascade lasers (ICL) has been demonstrated in a wide range of different applications. However, it is still often limited to bulky tabletop systems using individual components such as dual laser setups, beam shaping elements, and discrete detectors. In this work, a versatile integrated ICL platform is investigated for tackling this issue. A RF-optimized, two-section ICL approach is employed, consisting of a short section typically used for efficient modulation of the cavity field and a long gain section. Such a laser is operated in reversed mode, with the entire Fabry-Pérot waveguide utilized as a semiconductor optical amplifier (SOA) and the electrically separated short section as detector. Furthermore, a racetrack cavity is introduced as on-chip single-mode reference generator. The field of the racetrack cavity is coupled into the SOA waveguide via an 800 nm gap. By external injection of a single mode ICL operating at the appropriate wavelength, a heterodyne beating between the on-chip reference and the injected signal can be observed on the integrated detector section of the SOA-detector.
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Affiliation(s)
- Sandro Dal Cin
- Institute of Solid State Electronics, TU Wien, Gusshausstrasse 25-25a, 1040Vienna, Austria
| | - Andreas Windischhofer
- Institute of Solid State Electronics, TU Wien, Gusshausstrasse 25-25a, 1040Vienna, Austria
| | - Florian Pilat
- Institute of Solid State Electronics, TU Wien, Gusshausstrasse 25-25a, 1040Vienna, Austria
| | - Michael Leskowschek
- Faculty of Physics, Faculty Center for Nano Structure Research, Christian Doppler Laboratory for Mid-IR Spectroscopy, University of Vienna, Boltzmanngasse 5, 1090Vienna, Austria
| | - Vito F. Pecile
- Faculty of Physics, Faculty Center for Nano Structure Research, Christian Doppler Laboratory for Mid-IR Spectroscopy, University of Vienna, Boltzmanngasse 5, 1090Vienna, Austria
- Vienna Doctoral School in Physics, University of Vienna, Boltzmanngasse 5, 1090Vienna, Austria
| | - Mauro David
- Institute of Solid State Electronics, TU Wien, Gusshausstrasse 25-25a, 1040Vienna, Austria
| | - Maximilian Beiser
- Institute of Solid State Electronics, TU Wien, Gusshausstrasse 25-25a, 1040Vienna, Austria
| | - Robert Weih
- Nanoplus Nanosystems and Technologies GmbH, Oberer Kirschberg 4, 97218Gerbrunn, Germany
| | - Johannes Koeth
- Nanoplus Nanosystems and Technologies GmbH, Oberer Kirschberg 4, 97218Gerbrunn, Germany
| | - Georg Marschick
- Institute of Solid State Electronics, TU Wien, Gusshausstrasse 25-25a, 1040Vienna, Austria
| | - Borislav Hinkov
- Institute of Solid State Electronics, TU Wien, Gusshausstrasse 25-25a, 1040Vienna, Austria
| | - Gottfried Strasser
- Institute of Solid State Electronics, TU Wien, Gusshausstrasse 25-25a, 1040Vienna, Austria
| | - Oliver H. Heckl
- Faculty of Physics, Faculty Center for Nano Structure Research, Christian Doppler Laboratory for Mid-IR Spectroscopy, University of Vienna, Boltzmanngasse 5, 1090Vienna, Austria
| | - Benedikt Schwarz
- Institute of Solid State Electronics, TU Wien, Gusshausstrasse 25-25a, 1040Vienna, Austria
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Li J, Xue Z, Shen F, Wang J, Li Y, Wang G, Liu K, Chen W, Gao X, Tan T. Erbium-doped fiber amplifier (EDFA)-assisted laser heterodyne radiometer (LHR) working in the shot-noise-dominated regime. OPTICS LETTERS 2023; 48:5229-5232. [PMID: 37831834 DOI: 10.1364/ol.501761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 09/09/2023] [Indexed: 10/15/2023]
Abstract
A near-infrared (NIR) laser heterodyne radiometer (LHR) using a 1603 nm distributed feedback (DFB) laser, associated with an erbium-doped fiber amplifier (EDFA), used as a local oscillator (LO) was developed. The EDFA was customized for automatic power control to amplify and stabilize the LO DFB laser power, which allowed to reduce baseline fluctuation and thus make the processed atmospheric transmission spectrum with higher precision. The operation of the EDFA-assisted LHR with a shot-noise-dominated performance was analyzed and experimentally achieved by optimizing the LO power. The performance of the developed LHR was evaluated and verified by measuring an atmospheric CO2 absorption spectrum, and the atmospheric CO2 column abundances were then retrieved based on the optimal estimation method (OEM). The results were in good agreement with the Greenhouse Gas Observation Satellite (GOSAT) data. The EDFA-assisted LHR firstly reported in this Letter has a potential to further improve the measurement precision of atmospheric greenhouse gases using ground-based LHR remote sensing.
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Wang J, Tu T, Zhang F, Shen F, Xu J, Cao Z, Gao X, Plus S, Chen W. External-cavity diode laser-based near-infrared broadband laser heterodyne radiometer for remote sensing of atmospheric CO 2. OPTICS EXPRESS 2023; 31:9251-9263. [PMID: 37157498 DOI: 10.1364/oe.482131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
A near-infrared broadband (1500-1640 nm) laser heterodyne radiometer (LHR) with a tunable external-cavity diode laser as the local oscillator is developed and the relative transmittance, which represents the absolute relationship between the measured spectral signals and the atmospheric transmittance, is derived. High-resolution (0.0087 cm-1) LHR spectra in the spectral region of 6248.5-6256 cm-1 were recorded for the observation of atmospheric CO2. Combined with the relative transmittance, the preprocessed measured LHR spectra, the optimal estimation method, and the Python scripts for computational atmospheric spectroscopy, the column-averaged dry-air mixing ratio of CO2 of 409.09 ± 8 ppmv in Dunkirk, France on February 23, 2019, was retrieved, which is consistent with GOSAT and TCCON data. The near-infrared external-cavity LHR demonstrated in the present work has a high potential for use in developing a robust, broadband, unattended, and all-fiber LHR for spacecraft and ground-based atmospheric sensing that offers more channel selection for inversion.
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Shen F, Hu X, Lu J, Xue Z, Li J, Tan T, Cao Z, Gao X, Chen W. Performance Characterization of a Fully Transportable Mid-Infrared Laser Heterodyne Radiometer (LHR). SENSORS (BASEL, SWITZERLAND) 2023; 23:978. [PMID: 36679777 PMCID: PMC9866246 DOI: 10.3390/s23020978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 01/08/2023] [Accepted: 01/12/2023] [Indexed: 06/17/2023]
Abstract
A fully transportable laser heterodyne radiometer (LHR), involving a flexible polycrystalline mid-infrared (PIR) fiber-coupling system and operating around 8 µm, was characterized and optimized with the help of a calibrated high temperature blackbody source to simulate solar radiation. Compared to a mid-IR free-space sunlight coupling system, usually used in a current LHR, such a fiber-coupling system configuration makes the mid-infrared (MIR) LHR fully transportable. The noise sources, heterodyne signal, and SNR of the MIR LHR were analyzed, and the optimum operating local oscillator (LO) photocurrent was experimentally obtained. The spectroscopic performance of the MIR LHR was finally evaluated. This work demonstrated that the developed fully transportable MIR LHR could be used for ground-based atmospheric sounding measurements of multiple trace gases in the atmospheric column. In addition, it also has high potential for applications on spacecraft or on an airborne platform.
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Affiliation(s)
- Fengjiao Shen
- School of Advanced Manufacturing Engineering, Hefei University, Hefei 230601, China
- Laboratoire de Physico-Chimie de l’Atmosphère, Université du Littoral Côte d’Opale, 59140 Dunkerque, France
| | - Xueyou Hu
- School of Advanced Manufacturing Engineering, Hefei University, Hefei 230601, China
| | - Jun Lu
- School of Advanced Manufacturing Engineering, Hefei University, Hefei 230601, China
| | - Zhengyue Xue
- School of Advanced Manufacturing Engineering, Hefei University, Hefei 230601, China
| | - Jun Li
- Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China
| | - Tu Tan
- Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China
| | - Zhensong Cao
- Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China
| | - Xiaoming Gao
- Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China
| | - Weidong Chen
- Laboratoire de Physico-Chimie de l’Atmosphère, Université du Littoral Côte d’Opale, 59140 Dunkerque, France
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Xue Z, Shen F, Li J, Liu X, Wang J, Wang G, Liu K, Chen W, Gao X, Tan T. A MEMS modulator-based dual-channel mid-infrared laser heterodyne radiometer for simultaneous remote sensing of atmospheric CH 4, H 2O and N 2O. OPTICS EXPRESS 2022; 30:31828-31839. [PMID: 36242257 DOI: 10.1364/oe.469271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 08/02/2022] [Indexed: 06/16/2023]
Abstract
The performance of a micro-electro-mechanical system (MEMS) modulator-based dual-channel mid-infrared laser heterodyne radiometer (MIR-LHR) was demonstrated in ground-based solar occultation mode for the first time. A MEMS mirror was employed as an alternative modulator to the traditional mechanical chopper, which makes the system more stable and compact. Two inter-band cascade lasers (ICL) centered at 3.53 µm and 3.93 µm, were employed as local oscillators (LO) to probe absorption lines of methane (CH4), water vapor (H2O) and nitrous oxide (N2O). The system stability greater than 1000 s was evaluated by Allan variance. The experimental MIR-LHR spectra (acquired at Hefei, China, on February 24th 2022) of two channels were compared and were in good agreement with simulation spectra from atmospheric transmission modeling. The mixing ratio of CH4, H2O and N2O were determined to be ∼1.906 ppm, 3069 ppm and ∼338 ppb, respectively. The reported MEMS modulator-based dual-channel MIR-LHR in this manuscript has great potential to be a portable and high spectral resolution instrument for remote sensing of multi-component gases in the atmospheric column.
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Impact of Lock-In Time Constant on Remote Monitoring of Trace Gas in the Atmospheric Column Using Laser Heterodyne Radiometer (LHR). REMOTE SENSING 2022. [DOI: 10.3390/rs14122923] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The time constant selected for lock-in amplification (LIA) has a crucial impact on observed line shapes in laser heterodyne spectroscopy, in particular in the case of ground-based remote monitoring of trace gas in the atmospheric column using laser heterodyne radiometer (LHR). Conventional simulation could not allow validation of LHR spectra measured in a real and complex atmospheric environment exhibiting large temporal and spatial variability (humidity, temperature, pressure, etc) that impact significantly the measured LHR spectra profiles. High-precision spectral measurement is thus crucial to avoid any spectral distortion resulting from the measurement. In this paper, the impact of LIA time constant on spectral line shape is investigated for LHR operating in continuous laser tuning mode, based on analysis of laboratory heterodyne spectra, in terms of signal-to-noise ratio (SNR), line width broadening, absorption depth and line shift. With respect to the given frequency scanning speed in continuous mode and to the halfwidth of the absorption feature to scan, a reasonable scanning time ΔTscan, the time needed for scanning laser frequency through the halfwidth ΔνHWHM of the absorption line, equal to or longer than 14 times of the LIA time constant τ is concluded in order to efficiently reduce the noise while without significant shift and distortion of the line shape. Experimental validation was carried out using a laser heterodyne absorption spectroscopy approach in the laboratory. Four different combinations of time constants τ and scanning time ΔTscan were used to record heterodyne spectra of a CH4 absorption line near 1242.00 cm−1 in continuous laser tuning mode. An optimal combination of a scanning time of 137 ms with a time constant of 1 ms was obtained. This optimal combination was used for ground-based measurements of CH4 and N2O in the atmospheric column by LHR. The extracted LHR spectrum is in good agreement with a referenced TCCON (Total Carbon Column Observing Network) FT-IR (Fourier-transform infrared) spectrum.
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