Cylindrical microlens external cavity for laser diode frequency control
US5636059A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 8, 1995 |
| Grant date | Jun 3, 1997 |
| Priority date | — |
| Expiry date | Feb 8, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S5/02325
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
This invention relates to a simple, compact, and robust, cylindrical microlens external cavity for laser diode frequency control. The microlens system makes possible a tunable laser diode that utilizes an orthogonal pair of collimating microlenses to form a short external cavity for longitudinal mode and frequency control. The resulting system generates a circular, collimated beam of single frequency, tunable laser radiation. A cylindrical microlens collimator has a powered surface that semi-collimates (i.e., collimates in one axis only) the light from a laser diode. This powered surface is placed so as to be the surface closest to the laser facet. A second lens surface opposite the powered surface, is located in the semi-collimated beam is planar. The second surface of the lens is flat and has a reflective coating. Hence, it provides feedback that is refocused (in one axis) onto the laser aperture. This leads to efficient light coupling back into the laser even if the reflectivity of the second surface is relatively low, and allows the use of lasers with only a single optical output. In another embodiment, a second microlens is used to circularize the beam from the first microlens…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.