Circulator‐Free Brillouin Photonic Planar Circuit. Issue 5 (18th March 2021)

• Record Type: Journal Article
• Authors: Liu, Yang; Choudhary, Amol; Ren, Guanghui; Choi, Duk‐Yong; Casas‐Bedoya, Alvaro; Morrison, Blair; Ma, Pan; Nguyen, Thach G.; Mitchell, Arnan; Madden, Stephen J.; Marpaung, David; Eggleton, Benjamin J.
• Is Part Of: Laser & photonics reviews. Volume 15:Issue 5(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-03-18
• Subjects: Brillouin scattering -- integrated photonics -- inter‐modal optical nonlinearity -- nonlinear optics; Lasers -- Periodicals; Photonics -- Periodicals; Lasers -- Périodiques; Photonique -- Périodiques; 621.36
• DOI: 10.1002/lpor.202000481
• Languages: English
• ISSNs: 1863-8880

Abstract

Abstract: On‐chip stimulated Brillouin scattering (SBS) that results from enhanced light–sound interactions, has recently demonstrated great applicability and versatility for signal generation and manipulation. Progress toward realizing fully integrated Brillouin photonic circuits is promising; however, the control and routing of on‐chip optical waves requires non‐reciprocal elements such as circulators, which is challenging and adds complexity. Here, a circulator‐free Brillouin photonic planar waveguide circuit which eliminates the need for separate non‐reciprocal elements is demonstrated. Backward inter‐modal Brillouin scattering (BIBS) is used in a planar photonic integrated circuit, for the first time, to provide Brillouin processing capability in a multi‐modal waveguide, conveniently allowing for the separation of counter‐propagating pump and signal using passive integrated mode‐selective filters. Using an As2 S3 –Si hybrid multi‐modal photonic circuit, inter‐optical‐mode energy transfer with a Brillouin gain coefficient of 280 m −1 W −1 is experimentally demonstrated, representing two orders of magnitude enhancement compared to conventional optical fibers. This on‐chip BIBS circuit allows for independent routing of pump and signal waves, showing resilience to the cross talk. The experimental demonstrations provide an important basis for achieving fully integrated Brillouin photonic circuits without requiring on‐chip circulators and fine spectral filtering, opening a new dimension for studying spatial‐dependent photon–phonon nonlinear dynamics. Abstract : Inter‐optical‐modal nonlinear light–sound interaction between counter‐propagating optical waves is demonstrated in a planar multi‐modal photonic hybrid integrated circuit. Such backward inter‐modal Brillouin scattering process enables signal processing, with a significantly simplified manner to control optical waves using passive integrated mode‐selective devices. This demonstration provides an important basis for achieving fully integrated Brillouin photonic circuits without requiring on‐chip non‐reciprocal devices.