https://doi.org/10.1007/s100530050167
Frequency doubling of a fibre-amplified 1083 nm DBR laser
1
European Laboratory for Non-Linear Spectroscopy (LENS) and
Istituto Nazionale Fisica della Materia (INFM), Largo Enrico Fermi
2, 50125 Firenze, Italy
2
Dipartimento di Fisica,
Università di Pisa, Piazza Torricelli 2, 56126 Pisa, Italy
3
Istituto Nazionale di Ottica (INO), Largo Enrico Fermi 6,
50125 Firenze, Italy
4
Istituto Nazionale Fisica della Materia
(INFM) and Dipartimento di Fisica, Politecnico di Milano, Piazza
Leonardo Da Vinci 32, 20133 Milano, Italy
Corresponding authors: a djek@cix.co.uk - b minardi@lens.unifi.it
Received:
25
February
1998
Accepted:
28
May
1998
Published online: 15 September 1998
A good frequency standard is required at 1083 nm for measurements
on the fine structure of helium and of the fine structure constant.
Several milliwatts of CW frequency-doubled light offers the prospect
of stabilisation to a Doppler-free hyperfine transition in molecular
iodine. The 1083 nm emission of an extended-cavity DBR diode
laser has been amplified using an ytterbium-doped fibre amplifier,
and applied to a type-I phase matched Mg:LiNbO3 crystal in a
high-Q fundamental-resonant cavity for frequency doubling. The
amplifier gain at 1083 nm under typical operating conditions
was 13.8 dB, with a coherent output power up to 63 mW, limited
by the maximum signal input power. The doubling cavity Q was
, and about 70% of the incident power was coupled
in. The maximum 2nd-harmonic conversion efficiency exceeded 20%
and provided an output power of 3.7 mW for making continuous frequency
scans of up to 600 MHz in the green. An optical spectrum analyser
at 541.5 nm showed fringes of 4.6 MHz full width half maximum,
close to the instrumental width.
PACS: 42.65.Ky – Harmonic generation, frequency conversion / 42.72.Ai – Infrared sources / 42.72.Bj – Visible and ultraviolet sources
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1998
