Fiber optic dispersion method and apparatus
US4750833A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 3, 1985 |
| Grant date | Jun 14, 1988 |
| Priority date | — |
| Expiry date | Dec 3, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01M11/336
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In a single mode fiber under test a direct measurement of transmissive dispersion, such as of colors or polarizations, is produced. In the measurement of chromatic dispersion, light is modulated in amplitude by a first, high frequency signal and between one wavelength and another by a second, low frequency signal. Light transmitted through a fiber under test is received by a photodetector providing an output which is compared to the high frequency reference for phase by a first phase-sensitive detector. The amplitude modulated output of the first phase-sensitive detector is compared by a second phase-sensitive detector, preferably a lock-in amplifier to the low frequency reference signal to provide a signal indicative of transmissive dispersion. Other forms of dispersion, including polarization dispersion, may be measured. A source is modulated at a first, high frequency. A second, low frequency signal is used to vary the light between the first transmissive parameter value and a second, namely a first polarization and a second polarization. The light is varied at the low frequency between two values of the independent variable with respect to which dispersion is measured.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.