Performance of injection lasers with external gratings
Abstract
The operating characteristics of large-area injection lasers in a cavity composed of laser, lens, and grating are studied in detail. Comparison of performances with various combinations of gratings, lenses, and internal absorbers is given. All microscope lenses of N.A. at least 0.3 perform well, but camera lenses are strikingly inferior. Both reflection and transmission gratings give good results. With reflection gratings, the threshold and external efficiency approximate the bare laser with cleaved uncoated facets. The transmission grating has a similar differential efficiency but higher threshold. Its projected beam is highly collimated, with spread equal to the angle subtended at the lens by the near field on the facet; differential efficiency approaches 15% and the spectral radiant intensity reaches 1 GW per steradian per micron. The power sharing between modes of the bare laser and the compound resonator, as well as the spectral width of the tuned diode, follow the same laws as the bare laser.
- Publication:
-
RCA Review
- Pub Date:
- March 1977
- Bibcode:
- 1977RCARv..38...33S
- Keywords:
-
- Gratings (Spectra);
- Injection Lasers;
- Laser Cavities;
- Lens Design;
- Spectral Resolution;
- Cavity Resonators;
- Collimation;
- High Resolution;
- Near Fields;
- Optical Resonators;
- Performance Tests;
- Spectral Line Width;
- Tuning;
- Lasers and Masers