8 research outputs found
Continuous frequency tuning of an external cavity diode laser significantly beyond the free spectral range by sweeping the injection current
In this study, the frequency of an external cavity diode laser with an
antireflection-coated laser diode was continuously tuned over a range of 14.8
GHz, which was 4.5 times larger than the free spectral range, by only sweeping
the injection current to the laser diode. Without the antireflection coating,
the tuning range was reduced to one-fifth of the free spectral range, and mode
hops occurred with hysteresis. The theoretical analysis starting from the
hysteresis indicated that an unexpectedly wide tuning is possible if the
longitudinal modes of the solitary laser diode vanish owing to antireflection
coating.Comment: 10 pages, 5 figure
Cryogenic-Sapphire-Oscillator-Based Reference Signal at 1 GHz with 10-15 Level Instability
International audienceWe describe a 1 GHz reference signal with 10-15 level fractional frequency stability for averaging times longer than 1 s, synthesized from a 10.8 GHz oscillation frequency of a cryogenic-sapphire-resonator-based ultra-stable oscillator and phase locked to a hydrogen maser with a time constant of about 1000 s. The degradation of the short term stability of the reference signal by phase locking to the hydrogen maser was evaluated. We also report on the implementation of the 1 GHz signal down converted to 5 MHz as a reference oscillator for a cesium atomic fountain frequency standard