Abstract:
We present an analysis of the spectral characteristics of distributed-feedback (DFB) laser resonators with thermally chirped distributed mirrors. Such DFB resonators have...Show MoreMetadata
Abstract:
We present an analysis of the spectral characteristics of distributed-feedback (DFB) laser resonators with thermally chirped distributed mirrors. Such DFB resonators have the interesting capability of producing a linewidth as narrow as a few kHz. The investigated devices are ytterbium-doped amorphous Al2O3 channel waveguides with a periodic Bragg grating inscribed into its SiO2 top cladding. The resonance in the spectral response of the resonator results from a distributed λ/4 phase-shift produced by increasing the waveguide width. Its frequency is determined by the period of the Bragg grating, whereas its linewidth is determined by the intrinsic losses and the outcoupling losses of the resonator. When such a device is optically pumped to achieve gain and eventually lasing, the grating period becomes thermally chirped, thereby influencing the spectral characteristics of the resonator. We investigate experimentally and via simulations the frequency and linewidth of the resonance in the presence of a thermally induced linear chirp on the grating profile. Experiments and simulations show good quantitative agreement.
Date of Conference: 02-06 July 2017
Date Added to IEEE Xplore: 04 September 2017
ISBN Information:
Electronic ISSN: 2161-2064