Abstract

The spectral linewidth of quantum cascade lasers (QCL) is a few megahertz, while the intrinsic linewidth is only a few hundred hertz. This work proposes to employ strong optical feedback to narrow the linewidth of QCLs without any phase control. It is found that strong optical feedback always reduces the linewidth for any feedback phase. In addition, we experimentally show that the spectral linewidth of the measured QCL is reduced from 7.6 MHz down to 107 kHz by optical feedback with a feedback ratio of -3.8 dB. The corresponding frequency noise below 100 kHz Fourier frequency is reduced by about 40 dB.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.