Mode partition noise screening apparatus
US5172383A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 8, 1991 |
| Grant date | Dec 15, 1992 |
| Priority date | — |
| Expiry date | Oct 8, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S5/0014
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Accurate mode partition data from a laser are collected simply and rapidly in accordance with the principles of the invention wherein the laser output is directed to a filter which separates a central longitudinal mode from the side modes. The filter operates to present all side modes in a predetermined wavelength range simultaneously and continuously at the output of the filter. By subsequently comparing the intensity or power in the side modes delivered to the filter output with a predetermined threshold, it is possible to determine the frequency of occurrence and magnitude of mode partition events for side modes in the predetermined wavelength range. In one exemplary embodiment, the filter is realized by the combination of a Fabry-Perot etalon, whose longitudinal axis is angled with respect to the longitudinal axis (propagation axis) of the laser output beam directed onto the filter, together with an external reflector which is parallel to the Fabry-Perot etalon to permit multi-passing of the beam between the Fabry-Perot etalon and the reflector. The beam is reflected by the Fabry-Perot etalon so that after two or more passes within the filter only the side modes are output by t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.