There are two kinds of exceptional points of degeneracy (EPD) in waveguides: those in the absence of loss and gain, related to slow light, and those where the waveguide has distributed gain and/or loss. Here, we discuss both kinds and highlight their differences. We show EPDs of order 2, 3, 4 and 6 in waveguides supporting two or three modes in each direction, and how the coalescence parameter is a good tool to measure the degree of degeneracy by measuring the angle between the eigenvectors (polarization states). In highlighting the differences between the two kinds of EPDs, we also show different sets of applications, which include sensors, delay lines, distributed amplifiers, antennas, and oscillators.
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Lasing with multimode guided waves with exceptional degeneracy
We will discuss two kinds of exceptional points of degeneracy in waveguides and their respective application in lasers. Such exceptional points occur in waveguides with balanced loss and gain (e.g., PT symmetry), and in waveguides without loss and gain (e.g., periodic Si waveguides). Waveguides with such exceptional points have a strong degeneracy of their wavenumbers and polarization states that enables specific wave physics, only found in these degenerate systems. We will discuss advantages and disadvantages of both concepts to conceive laser regimes, related to high power, high spectral purity, high efficiency, etc, and show some realistic designs involving Si ridge waveguides.
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- Award ID(s):
- 1711975
- NSF-PAR ID:
- 10421533
- Editor(s):
- Subramania, Ganapathi S.; Foteinopoulou, Stavroula
- Date Published:
- Journal Name:
- Proceedings Volume PC12196, Active Photonic Platforms 2022; PC121961M (2022)
- Page Range / eLocation ID:
- SPIE Nanoscience + Engineering, 2022, San Diego
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1117/12.2634283
