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Wavelength shifting is an important process in fiber-optical communications, and is implicated for example, for transferring information between low-loss transmission windows, typically between 1.3 µm and 1.55 µm. This is normally achieved using optical-electrical-optical (OEO) switches that results in speed bottlenecks. Here, we demonstrate an all-optical wavelength shifting scheme using quantum cascade lasers (QCLs)1 for the generation of sidebands on an optical telecom carrier at room temperature, potentially being considerably faster than OEOs. The process is based on resonant nonlinearities where phase matching is less critical. This work is the first demonstration of telecom sideband generation at room temperature with QCLs, where previous works with QCLs 2-4 have been limited to optical pumps in the near-infrared range (~800 nm).
The wavelength shift in the telecom domain was achieved by nonlinear sideband generation using a modified MIR QCL (lambda=10µm), based on InGaAs/AlInAs quantum wells, and a resonant telecom pump, permitting to shift from 1.3 µm to 1.55 µm and vice-versa. Demonstrations at room temperature are shown. THz sideband generation with InGaAs/AlInAs THz QCLs are also demonstrated, compared to those in the MIR and correlated with nonlinear susceptibility calculations.
To conclude, sideband generation in the telecom range has been demonstrated at room temperature. This demonstration in the telecom range will further permit novel approaches for the QCL stabilization/injection locking, and the up-conversion of the MIR emission to the telecom domain.
1. J. Faist, et al., Science 264 (5158), 553-556 (1994).
2. J. Madeo, et al., Nat Photonics 6 (8), 519-524 (2012).
3. P. Cavalie, et al., Appl Phys Lett 102 (22) (2013).
4. S. Houver, et al., J. Tignon and S. S. Dhillon, Opt Express 23 (4), 4012-4020 (2015).
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