Ultrahigh Transmission Optical Nanofibers

TL;DR

This paper details a reproducible method for fabricating ultrahigh transmission optical nanofibers with minimal loss, enabling high-power transmission and improved mode control, significantly advancing fiber performance for quantum and photonic applications.

Contribution

The paper introduces a precise fabrication protocol achieving record-low loss and high transmission in optical nanofibers, with detailed procedures and validation against simulations.

Findings

Achieved 99.95% single-mode transmission with minimal taper loss.

Demonstrated over 400 mW high vacuum transmission capability.

Provided the first spectrogram of a fundamental mode launch without asymmetric mode excitation.

Abstract

We present a procedure for reproducibly fabricating ultrahigh transmission optical nanofibers (530 nm diameter and 84 mm stretch) with single-mode transmissions of 99.95 $ \pm$ 0.02%, which represents a loss from tapering of 2.6 $\,\times \,$ 10$^{-5}$ dB/mm when normalized to the entire stretch. When controllably launching the next family of higher-order modes on a fiber with 195 mm stretch, we achieve a transmission of 97.8 $\pm$ 2.8%, which has a loss from tapering of 5.0 $\,\times \,$ 10$^{-4}$ dB/mm when normalized to the entire stretch. Our pulling and transfer procedures allow us to fabricate optical nanofibers that transmit more than 400 mW in high vacuum conditions. These results, published as parameters in our previous work, present an improvement of two orders of magnitude less loss for the fundamental mode and an increase in transmission of more than 300% for higher-order modes, when following the protocols detailed in this paper. We extract from the transmission during the pull, the only reported spectrogram of a fundamental mode launch that does not include excitation to asymmetric modes; in stark contrast to a pull in which our cleaning protocol is not followed. These results depend critically on the pre-pull cleanliness and when properly following our pulling protocols are in excellent agreement with simulations.