| 摘要 |
An optical wavelength interrogator for a fibre optic sensing system has a reference wavelength unit to make calibrated wavelengths available to the system. A wavelength swept optical source 1, such as a tunable laser, produces light which is coupled to a master unit 11 and to several fibre optic sensor strings 7 which may contain fibre Bragg gratings (FBGs). The master unit has a wavelength reference 8 such as a fixed cavity interference filter, reference FBG, etalon, or gas absorption cell. The master unit determines the reference wavelength of the swept source 1 and may be used to calibrate the wavelength versus time profile of the swept source. A reference FBG 5 may also be coupled to the master unit to allow absolute wavelengths to be determined. The output from the master unit may be used as feedback to control the wavelength sweep of the tunable source. The outputs from the sensor strings 7 are coupled to a plurality of slave units 13 separate from the master unit. |
