Current Control Technology for Quantum Cascade Laser and Other Applications
Available for licensing in all fields
Summary
For laser-based trace gas sensing applications, precision, stability and reliability are key. This is true for quantum cascade laser-based systems, as well as for those based on more traditional semiconductor laser diodes. A poor choice of power supply can compromise the functionality and reliability of such systems, and reduce their utility or even damage laser devices. Researchers at PNNL have developed a current controller technology that powers quantum cascade lasers (QCLs) safely, and for optimum performance.
Comparable current controllers commercially available today often force a choice between low noise and stability versus functionalities such as rapid control. This can result in excess noise, resonances, drifts, or even spiking when large command inputs are given. The QCLx series of controller developed at PNNL uniquely overcomes these difficulties allowing for noise levels close to the theoretical minimums, excellent long term stability, and smooth, rapid control.
The QCLx series of controller is safe to use with QCLs, and the resulting narrow laser line width and stable output wavelength contribute to improved sensitivity and selectivity in demanding sensor applications. In cases where small quantities of specific gaseous compounds are to be detected in the presence of interferents, these attributes can help the sensor designer achieve lower false positives and negatives.
In addition to the base controller developed in 2002, PNNL scientists have also developed the following improvements to the base controller:
- a means to pulse the power controller to provide pulses down to approximately 10 microseconds without increasing noise or reducing stability;
- a method and apparatus to quickly modulate a QCL to produce waveforms that are beyond the capabilities of currently available technology;
- a pulse width modulated current controller that provides exceptionally stable and low-noise current at low power consumption and minimal thermal loading;
- a means to reduce ringing and accelerate modulation response time by temporarily providing forced input from an auxiliary network.
Advantages
This collection of technology is designed to provide low noise, highly stable current in either pulsed or continuous mode to QCL’s and potentially other applications requiring it. Other features of the technology include relatively low power consumption and thermal loads that make QCL’s much more “field deployable.” Creation of waveforms not presently available in QCL systems is also enabled.
Related Links
- Publication: Free-running frequency stability of mid-infrared quantum cascade lasers - Optics Letters, Vol. 27, No. 3, February 1, 2002
- Publication: Frequency stabilization of quantum-cascade lasers by use of optical cavities - Optics Letters, Vol. 27, No. 24 / December 15, 2002
- Publication: Stabilization, injection and control of quantum cascade lasers, and their application to chemical sensing in the infrared - Elsevier, Spectrochimica Acta Part A 60 (2004)
