On-Chip Optical Nonreciprocity Using an Active Microcavity

Abstract

Optically nonreciprocal devices provide critical functionalities such as light isolation and circulation in integrated photonic circuits for optical communications and information processing, but have been difficult to achieve. By exploring gain-saturation nonlinearity, we demonstrate on-chip optical nonreciprocity with excellent isolation performance within telecommunication wavelengths using only one toroid microcavity. Compatible with current complementary metal-oxide-semiconductor process, our compact and simple scheme works for a very wide range of input power levels from ~10 microwatts down to ~10 nanowatts, and exhibits remarkable properties of one-way light transport with sufficiently low insertion loss. These superior features make our device become a promising critical building block indispensable for future integrated nanophotonic networks.

Demonstration of a chip-based optical isolator with parametric amplification

“…In comparison with previous works131415161718192021222324 utilizing nonlinearities, our framework shows explicitly remarkable isolating performance in suppressing the transmission of backward-propagating noise with signal fields launched from both directions simultaneously. Unlike prior work172123, our scheme achieves appreciable isolation functionality with only one coupling fibre, a significant non-trivial step forward.…”

“…In contrast to linear isolators, considerable enthusiasm has been devoted to breaking Lorentz reciprocity with use of various nonlinearities. Among these, to name a few, non-reciprocal light transmission has recently been demonstrated with second-order nonlinearity1314, Kerr or Kerr-type nonlinearities1516, gain/absorption saturation171819, Raman amplification20, stimulated Brillouin scattering21, Bragg scattering22, thermo-optic effects23 and with opto-acoustic effects24.…”

“…Of these nonlinear means131415161718192021222324, asymmetric transmission contrast is typically demonstrated when a wave is injected in either forward or backward direction but never both. The lack of an experiment on the simultaneous presence of waves from both directions causes people to question whether these nonlinear isolators could be actually capable of providing complete isolation under practical operating conditions.…”

Optical Isolation with Nonlinear Topological Photonics

“…A nonlinear photonic structure with strongly intensitydependent transmittance can serve as the basis for an op- tical isolator [10,16,20,21,23,24]. To accomplish this, we introduce couplings η A and η B , as shown schematically in Fig.…”

“…Magneto-optic isolators are the most widely used in current technology, but are challenging to incorporate into on-chip optical circuits [2][3][4]. For this reason, there has been a great deal of research into isolator designs based on spatio-temporal modulation [5,6] and nonlinear materials [2,[7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26].…”