Multigas detection using a sample-grating distributed Bragg reflector diode laser

Abstract

A sample-grating distributed Bragg reflector (SG-DBR) laser with 18 preprogrammed channels operating at 1540-1580 nm is characterized and compared for use as a source of tunable diode laser gas absorption spectroscopy. Two gases, CO and CO2, were targeted in this study by direct absorption spectroscopy and wavelength modulation spectroscopy with second-harmonic detection. In addition, the detectability of sample optical thickness is reported. Potential extensions of this research in the future are assessed using the SG-DBR diode laser as a source for tunable diode laser gas absorption spectroscopy.

Gas Sensing System Based on an All-Fiber Photothermal Microcell

“…In this regard it is very important to selectively monitor concentrations of various hazardous gases and particles that might be present in the environment. Optical gas sensing principles [1,2] showed high potential due to high selectivity, as most gas molecules have distinctive optical resonant frequencies. Merging bulk optical setups with optical fibers can add further advantages and flexibility to the sensing system, e.g., the possibility for remote sensing (optical fibers allow for transmission over large distances), electric passivity (no electric components within the sensing area), immunity to electromagnetic interference, and compatibility with explosive/hazardous environments.…”

“…A common part of many optical gas sensing principles is a gas cell, which contains the analyzed gas that is illuminated by excitation light with wavelengths aligned to the absorption peaks of the target species within the analyzed gas. The absorption of light by target species is then identified by using different principles, like gas absorption spectroscopy [3], tunable diode laser absorption spectroscopy (TDLAS) [1], photo-acoustic absorption spectroscopy [4], measurement of the anomalous dispersion of refractive index [2], and many others. While these sensing principles are well established, gas absorption cells remain relatively large (long optical path lengths are required), complex for production (which is associated with increased cost), require relatively large sample volumes, are sensitive to vibrations, temperature, and other environmental impacts, and have limited compatibility with optical fibers.…”

A Widely Tunable Three-Section DBR Lasers for Multi-Species Gas Detection

“…Since the tuning range of DFB lasers is relatively small (one or two nanometers), it need multiple lasers in the multiple gases sensing system [7], which make the system very complex. In application, cost-effective monitoring, rapid measurement and equipment miniaturization is of great importance for an excellent gas sensing system, thus the widely tunable semiconductor lasers show their advantages when they are applied in such system [8,9]. At present, because of the rapid development of communications, the DBR lasers emitting at 1.5 and 1.3 µm have been reported [10][11][12][13][14].…”

Distributed Bragg reflector laser (1.8 \mu m) with 10 nm wavelength tuning range

“…In contrast, a distributed Bragg reflector (DBR) laser with single-mode operation can provide better performance due to its large tuning range, compared to DFB lasers. As the absorbing lines of the detected gases are covered in the tuning range of the DBR laser, it is convenient to detect several gases simultaneously using a single DBR laser [2,3] . At present, due to the rapid development of telecommunications, many DBR lasers in the wavelength range from 1.3 to 1.6 μm have been reported [4][5][6][7][8] .…”