Multiple Wavelength DBR Laser
- Detailed Technology Description
- The invention is a general design for a simultaneously emitting, dual wavelength diode laser for electronically simpler and more efficient remote sensing (e.g., water vapor on Mars, wind/weather analysis, airborne toxins.)
- Countries
- United States
- Application No.
- 6728290
- *Abstract
-
The invention is a general design for a simultaneously emitting, dual wavelength diode laser for electronically simpler and more efficient remote sensing (e.g., water vapor on Mars, wind/weather analysis, airborne toxins.)
DESCRIPTION/DETAILS
Remote sensing uses light detection and ranging (lidar) to send two wavelengths of light through a gas or the atmosphere. One emitted wavelength is chosen to be absorbed by the species, while the other wavelength is not; a comparative ratio of the reflective intensities of the two wavelengths provides a measurement of absorption and therefore the amount of concentration of the species. Traditionally, this process involves two repetitive, serial actions: first, shooting laser light on frequency; then, tuning the laser using the absorption frequency, and shooting the laser again. This invention is a laser that simultaneously produces the two wavelengths, has simpler electronic controls, and can be operated with battery power.
The design has the potential to generate numerous, simultaneous laser wavelengths with careful, cascaded assembly of "blocks" (essentially discrete wavelength-specific resonators having the same gain medium, described fully in the patent). It also includes a surface Bragg grating to permit wavelength tuning.
The invention uses an edge-emitting laser, along with a novel variation on a Bragg grating: a much deeper, surface grating that has higher reflectivity and interaction with the optical field than standard gratings, added to an otherwise finished device. This last feature enables addition of multiple gratings, as needed.
The device can be tuned during operation to allow a precision adjustment of the wavelengths. An added electrode and current alter the grating spacing by generating heat, which in turn changes the refractive index and results in a small wavelength shift. The advantage of this invention lies in its integrated, simple solution to a process that would otherwise require coupling light from separate lasers into fibers, with associated loss, or using integrated waveguides.
APPLICATIONS
- Remote Sensing: Differential absorption (or lidar) for measurement of atmospheric content of various species, for metereology, security, and defense.
- Telecommunications: Wavelength division multiplexing (WDM).
- Cost Savings: This technology reduces costs in packaging, control, and interconnects.
- Tunable: Wavelengths can be adjusted via Bragg gratings to match absorption characteristics of the species to be measured.
- Extendable: The basic concept can be cascaded to simultaneously produce a large number of wavelengths.
For more information about this technology, please contact the University of Illinois at Urbana-Champaign Office of Technology Management at otm@illinois.edu.
- *IP Issue Date
- None
- *IP Type
- Utility
- Country/Region
- USA
