Title :
Remote sensing of methane gas by differential absorption measurement using a wavelength tunable DFB LD
Author :
Shimose, Y. ; Okamoto, T. ; Maruyama, A. ; Aizawa, M. ; Nagai, H.
Author_Institution :
Anritsu Corp., Kanagawa, Japan
Abstract :
In the method described a single wavelength tunable distributed-feedback laser diode (DFB LD) in the 1.65- mu m region is used to emit two different wavelengths of equal power which are modulated 180 degrees out of phase with each other at a frequency of 10 kHz. One of the two wavelengths is frequency stabilized via a methane gas cell and a feedback system equipped with a lock-in amplifier. A sensitivity of 4 p.p.m.-m methane in 1-atm nitrogen has been achieved. This light source has greatly simplified the setup for the measurements of this kind.<>
Keywords :
chemical variables measurement; distributed feedback lasers; laser frequency stability; laser tuning; organic compounds; remote sensing by laser beam; semiconductor junction lasers; spectrochemical analysis; 1.65 micron; differential absorption measurement; feedback system; frequency stabilised wavelength; gas fuel safety; light source; lock-in amplifier; methane gas; remote sensing; wavelength tunable DFB LD; Absorption; Amplifiers; Diode lasers; Frequency; Laser feedback; Light sources; Nitrogen; Phase modulation; Remote sensing; Tunable circuits and devices;
Journal_Title :
Photonics Technology Letters, IEEE
