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Main Authors: Bhuckory, Radhika R., Kacmoli, Sara, Sivco, Deborah L., Gmachl, Claire
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2505.05382
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author Bhuckory, Radhika R.
Kacmoli, Sara
Sivco, Deborah L.
Gmachl, Claire
author_facet Bhuckory, Radhika R.
Kacmoli, Sara
Sivco, Deborah L.
Gmachl, Claire
contents Ring lasers exhibit rich operational regimes such as unidirectional, bidirectional, or bistable operation. The two-mode dynamics of the counter-propagating modes - clockwise (CW) and counterclockwise (CCW) and their selection, have gained attention in the mid-infrared; however, the underlying switching mechanism has been largely unexplored. Previously, we experimentally demonstrated robust and deterministic mode selection in a ring quantum cascade laser (QCL) with an active outcoupling waveguide. Here, we apply the Lang-Kobayashi framework to our system to model the effects of spontaneous emission in the waveguide arms as well as amplified optical feedback from the facets on the mechanics of mode switching. We find that coherent feedback from facet reflections agrees upwards of 93\% with the experimental behavior, indicating that amplified feedback is the dominant mechanism driving the mode selection dynamics.
format Preprint
id arxiv_https___arxiv_org_abs_2505_05382
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Amplified Feedback and Spontaneous Emission Injection in Quantum Cascade Ring Laser Systems
Bhuckory, Radhika R.
Kacmoli, Sara
Sivco, Deborah L.
Gmachl, Claire
Optics
Ring lasers exhibit rich operational regimes such as unidirectional, bidirectional, or bistable operation. The two-mode dynamics of the counter-propagating modes - clockwise (CW) and counterclockwise (CCW) and their selection, have gained attention in the mid-infrared; however, the underlying switching mechanism has been largely unexplored. Previously, we experimentally demonstrated robust and deterministic mode selection in a ring quantum cascade laser (QCL) with an active outcoupling waveguide. Here, we apply the Lang-Kobayashi framework to our system to model the effects of spontaneous emission in the waveguide arms as well as amplified optical feedback from the facets on the mechanics of mode switching. We find that coherent feedback from facet reflections agrees upwards of 93\% with the experimental behavior, indicating that amplified feedback is the dominant mechanism driving the mode selection dynamics.
title Amplified Feedback and Spontaneous Emission Injection in Quantum Cascade Ring Laser Systems
topic Optics
url https://arxiv.org/abs/2505.05382