Open AccessIntensity-independent wavelength locking of diode lasers to a spectral slope of a fiber-optic sensor for ultrasonic detection
Author(s) -
Lei Hu,
Ming Han
Publication year - 2017
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.25.031017
Subject(s) - optics , materials science , fiber bragg grating , intensity modulation , fiber optic sensor , laser , distributed feedback laser , optical fiber , fiber laser , laser diode , wavelength , modulation (music) , amplitude modulation , phase modulation , optoelectronics , frequency modulation , physics , phase noise , telecommunications , acoustics , computer science , radio frequency
We propose and demonstrate a simple and low-cost method to lock the wavelength of a diode laser to a point with a particular normalized slope on the spectrum of a fiber-optic sensor. The wavelength locking point is independent of the laser intensity variations. The locking involves simultaneously and independently modulating both the laser wavelength and the laser intensity. On the spectral slope, the wavelength modulation is also converted to intensity modulation that is superimposed to the direct intensity modulation. The error signal is the amplitude of the overall intensity modulation. We demonstrate a potential application of the locking method in a fiber-optic ultrasonic detection system using a distributed feedback diode laser and a phase-shifted fiber Bragg grating sensor.