{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,25]],"date-time":"2025-10-25T12:17:49Z","timestamp":1761394669303,"version":"build-2065373602"},"reference-count":9,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2015,7,6]],"date-time":"2015-07-06T00:00:00Z","timestamp":1436140800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>A time difference method to conveniently measure the phase shift between output wavelength and intensity of distributed feedback laser diodes (DFB-LDs) was proposed. This approach takes advantage of asymmetric absorption positions at the same wavelength during wavelength increase and decrease tuning processes in the intensity-time curve by current modulation. For its practical implementation, a measurement example of phase shift was demonstrated by measuring a time difference between the first time and the second time attendances of the same gas absorption line in the intensity-time curve during one sine or triangle modulation circle. The phase shifts at modulation frequencies ranging from 50 Hz to 50 kHz were measured with a resolution of 0.001\u03c0. As the modulation frequency increased the shift value increased with a slowed growth rate.<\/jats:p>","DOI":"10.3390\/s150716153","type":"journal-article","created":{"date-parts":[[2015,7,6]],"date-time":"2015-07-06T12:21:05Z","timestamp":1436185265000},"page":"16153-16161","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["A Time Difference Method for Measurement of Phase Shift between Distributed Feedback Laser Diode (DFB-LD) Output Wavelength and Intensity"],"prefix":"10.3390","volume":"15","author":[{"given":"Yongning","family":"Liu","sequence":"first","affiliation":[{"name":"School of Information Science and Engineering, Shandong University, Jinan 250100, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jun","family":"Chang","sequence":"additional","affiliation":[{"name":"School of Information Science and Engineering, Shandong University, Jinan 250100, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jie","family":"Lian","sequence":"additional","affiliation":[{"name":"School of Information Science and Engineering, Shandong University, Jinan 250100, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zhaojun","family":"Liu","sequence":"additional","affiliation":[{"name":"School of Information Science and Engineering, Shandong University, Jinan 250100, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Qiang","family":"Wang","sequence":"additional","affiliation":[{"name":"School of Information Science and Engineering, Shandong University, Jinan 250100, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Cunguang","family":"Zhu","sequence":"additional","affiliation":[{"name":"School of Information Science and Engineering, Shandong University, Jinan 250100, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2015,7,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"421","DOI":"10.7452\/lapl.201210015","article-title":"Detection of water vapor concentration based on differential value of two adjacent absorption peaks","volume":"9","author":"Wang","year":"2012","journal-title":"Laser Phys. Lett."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"31540","DOI":"10.1364\/OE.21.031540","article-title":"Acquisition of phase-shift fiber grating spectra with 23.5 femtometer spectral resolution using DFB-LD","volume":"21","author":"Zhu","year":"2013","journal-title":"Opt. Express"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"5803","DOI":"10.1364\/AO.38.005803","article-title":"Theoretical description based on Fourier analysis of wavelength-modulation spectrometry in terms of analytical and background signals","volume":"38","author":"Pawel","year":"1999","journal-title":"Appl. Opt."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Hodgkinson, J., and Tatam, R.P. (2013). Optical gas sensing: A review. Meas. Sci. 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J."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/15\/7\/16153\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T20:48:45Z","timestamp":1760215725000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/15\/7\/16153"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2015,7,6]]},"references-count":9,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2015,7]]}},"alternative-id":["s150716153"],"URL":"https:\/\/doi.org\/10.3390\/s150716153","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2015,7,6]]}}}