Abstract
A new transportable frequency comb has been developed at the National Physical Laboratory. The transportable frequency comb is based around a MenloSystems FC1500 optical frequency synthesizer, which is capable of measuring any frequency between 500 and 2100nm. Measurements made by the comb while off-sites are referenced to the SI second via a global positioning system (GPS)-disciplined Rapco 2804AR rubidium oscillator. All components of the system (except for the GPS antenna) have been integrated into a single mobile unit. Measurements of high-stability narrow-band optical sources using this system, with either the GPS-disciplined oscillator or a hydrogen maser as a reference, are described. Some of these measurements were made simultaneously with a hydrogen-maser-referenced Ti:sapphire-based comb. It was found that the GPS-referenced transportable comb has a fractional inaccuracy of better than 4×10-12 (averaged over several hours) when compared with the maser-referenced Ti:sapphire comb, and a fractional frequency instability of 1×10-12 for an averaging time of 10s. It was also demonstrated that continuous frequency measurements are possible with this system over a period of 60h or more. © The Institution of Engineering and Technology.
| Original language | English |
|---|---|
| Pages (from-to) | 182-187 |
| Number of pages | 6 |
| Journal | IET Optoelectronics |
| Volume | 2 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - 2008 |