On-chip polarization rotator for type I second harmonic generation

Eric J. Stanton; Lin Chang; Weiqiang Xie; Aditya Malik; Jon Peters; Jeff Chiles; Nima Nader; Gabriele Navickaite; Davide Sacchetto; Michael Zervas; Kartik Srinivasan; John E. Bowers; Scott B. Papp; Sae Woo Nam; Richard P. Mirin

arXiv · 1907.13626

On-chip polarization rotator for type I second harmonic generation

Eric J. Stanton·Lin Chang·Weiqiang Xie·Aditya Malik·Jon Peters·Jeff Chiles·Nima Nader·Gabriele Navickaite·Davide Sacchetto·Michael Zervas·Kartik Srinivasan·John E. Bowers·Scott B. Papp·Sae Woo Nam·Richard P. Mirin

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Abstract

We demonstrate a polarization rotator integrated at the output of a GaAs waveguide producing type I second harmonic generation (SHG). Form-birefringent phase matching between the pump fundamental transverse electric (TE) mode near 2.0 $\mu$m wavelength and the signal fundamental transverse magnetic (TM) mode efficiently generates light at 1.0 $\mu$m wavelength. A SiN waveguide layer is integrated with the SHG device to form a multi-functional photonic integrated circuit. The polarization rotator couples light between the two layers and rotates the polarization from TM to TE or from TE to TM. With a TE-polarized 2.0 $\mu$m pump, type I SHG is demonstrated with the signal rotated to TE polarization. Passive transmission near 1.0 $\mu$m wavelength shows ~80 % polarization rotation across a broad bandwidth of ~100 nm. By rotating the signal polarization to match that of the pump, this SHG device demonstrates a critical component of an integrated self-referenced octave-spanning frequency comb. This device is expected to provide crucial functionality as part of a fully integrated optical frequency synthesizer with resolution of less than one part in 10$^{14}$.

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Eric J. Stanton, Lin Chang, Weiqiang Xie, Aditya Malik, Jon Peters, Jeff Chiles, Nima Nader, Gabriele Navickaite, Davide Sacchetto, Michael Zervas, Kartik Srinivasan, John E. Bowers, Scott B. Papp, Sae Woo Nam, Richard P. Mirin. 2019-07-31. On-chip polarization rotator for type I second harmonic generation. https://arxiv.org/abs/1907.13626

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