A comparison is made between unpackaged and packaged distributed feedback (DFB) fibre lasers
using the Michelson interferometer configuration for delayed self-heterodyne interferometery (MIDSHI)
to ascertain the improvements to the external environmental noise, quantified by reductions in
the Gaussian linewidth. Voigt fitting is used to extract and separate out the Lorentzian and Gaussian
linewidth contributions and therefore the associated sources of noise. Significant improvements in the
Gaussian linewidth were achieved as a result of significant reductions in the sensitivity of the DFB
laser to external perturbations using packaging. However, a broadening of the laser Lorentzian
linewidth was observed.
The temperature profile of the reaction zone inside the substrate tube of a modified chemical vapour deposition
(MCVD) optical fibre perform lathe has been characterised using thermal chirp compensated ultra-high
temperature stable regenerated optical fibre Bragg gratings (FBGs). Results indicate significant differences in
measured internal temperatures than those predicted theoretically or measured externally.