Davis, Nicholas M.Lynch, S. F.Gates, J. C.Hodgkinson, JaneSmith, P. G. R.Tatam, Ralph P.2019-10-012019-10-012019-09-25Davis NM, Lynch SF, Gates JC, et al., (2019) Spectroscopic gas detection using a Bragg grating - stabilized external cavity laser, custom written in planar integrated silica-on-silicon. Optics Express, Volume 27, Issue 20, pp. 29034-290441094-4087https://doi.org/10.1364/OE.27.029034https://dspace.lib.cranfield.ac.uk/handle/1826/14579We present the development of an external cavity Bragg grating stabilized laser for tunable diode laser spectroscopy (TDLS). Our design uses a planar integrated silica-on-silicon platform incorporating a custom written Bragg grating as the wavelength-selective element of the laser cavity. We have developed a prototype singlemode laser at 1651 nm and performed a detailed characterization of its performance for the purpose of spectroscopic measurement of methane at this wavelength using a 25 cm path-length single-pass cell. Mode hop-free tuning of 0.13 nm has been demonstrated at frequencies of up to 10 kHz. A single-point limit of detection for TDLS of ΔI/I0 = 8.3 × 10−5 AU was achieved, which is consistent with the performance of standard distributed feedback lasers. The new device exhibits a side-mode suppression ratio of −40 dB and a low RIN of <−150 dB/Hz, and thus avoids the high levels of noise or instability normally associated with larger, mechanically driven external cavity lasers. The silica-on-silicon platform has the potential for low-volume manufacturing of special lasers at the custom wavelengths required for gas detection, without the need for investment in foundry solutions.enAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/Article24662174