Continuously Tunable 3-5 Micrometers Single-Frequency Laser Source
Abstract
The goal of this project is to develop a 3-5 micrometer continuously tunable single-frequency laser source. Our approach uses an external cavity (EC) and various tuning elements in conjunction with a semiconductor optical amplifier (SOA). Optically pumped, amorphous-silicon ridge-waveguide lasers, grown via molecular-beam epitaxy, were developed that could function as curved-ridge-waveguide SOAs. The lasers operate at a temperature of 295 K, where they output 7 mW per facet. The wavelength is 3 micrometers. Comparison with a stripe laser in the same material suggests that a flaw in the ridge metal mask induces losses that increase the threshold pump power and similarly reduce the external efficiency. The lateral far-field for the ridge-waveguide lasers are multi-lobed, indicating that the lasers are not operating in the fundamental lateral mode. Sarnoff designed and constructed an EC that is compatible with the use the SOAs. The EC is 8 cm long with a footprint less than 1 sq ft. Sarnoff designed, fabricated and partially characterized the tuning etalon that selects one longitudinal cavity mode. It is an air-gap etalon using silicon-based mirrors and a 16.5 micrometers-thick polycarbonate spacer ring. The etalon free spectral range is 9 THz, which is the estimated SOA gain width.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 08, 2003
- Accession Number
- ADA411611
Entities
People
- Ramon U. Martinelli
Organizations
- Sarnoff Corporation