Open AccessExternal cavity diode lasers with 5kHz linewidth and 200nm tuning range at 155μm and methods for linewidth measurement
Author(s) -
Shayne Bennetts,
Gordon McDonald,
Kyle Hardman,
J. E. Debs,
Carlos C. N. Kuhn,
John Close,
Nicholas Robins
Publication year - 2014
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.22.010642
Subject(s) - laser linewidth , optics , materials science , laser , semiconductor laser theory , diode , full width at half maximum , injection seeder , optoelectronics , fiber laser , tunable laser , laser diode , physics
Two simple external cavity diode laser designs using fibre pigtailed gain chips are tested and their properties compared with a high end DBR fibre laser. These ECDLs demonstrate a FWHM linewidth as low as 5.2kHz with a fitted Lorentzian FWHM linewidth as low as 1.6kHz. Tuning ranges of 200nm covering 1420nm to 1620nm were demonstrated. To the best of our knowledge these are the narrowest linewidth and most broadly tunable external cavity diode lasers reported to date. The improvement in linewidth is attributed to greatly enhanced acoustic isolation allowed by using fiber coupled gain chips and by replacing kinematic mounts with a pair of rotatable wedges for cavity alignment which eliminates acoustic resonances. A detailed description and discussion of techniques used to characterize the frequency noise and linewidths of these lasers is provided.