Optical nonreciprocal devices based on magneto-optical phase shift in silicon photonics

Abstract

Silicon waveguide optical nonreciprocal devices that use the magneto-optical phase shift are reviewed. The phase shift caused by the first-order magneto-optical effect is effective in realizing optical nonreciprocal devices on semiconductor waveguide platforms. In a silicon-on-insulator waveguide, the low refractive index of the buried oxide layer contributes to the large penetration of the optical field into a magneto-optical material used as an over-cladding layer. This enhances the magneto-optical phase shift and, hence, contributes greatly to reducing the device footprint. A surface-activated direct bonding technique plays a key role in the fabrication of magneto-optical nonreciprocal devices. This technique makes it possible to use a high-quality single-crystalline magneto-optical garnet that exhibits a large first-order magneto-optical effect. An optical isolator based on the magneto-optical phase shift was demonstrated in a silicon waveguide with an optical isolation ratio as high as 30 dB and an insertion loss of 13 dB at a wavelength of λ = 1548 nm. Furthermore, a four-port optical circulator was demonstrated with maximum isolation ratios of 33.5 and 29.1 dB in the cross and bar ports, respectively, at λ = 1543 nm.

Non‐Reciprocity in High‐Q Ferromagnetic Microspheres via Photonic Spin–Orbit Coupling

“…Non‐reciprocal optical devices such as the optical isolators and circulators are important in the development of photonic integrated circuits . The conventional non‐reciprocal optical devices are based on Faraday effect via an externally applied magnetic field in the direction of the propagation.…”

“…Non-reciprocal optical devices such as the optical isolators and circulators are important in the development of photonic integrated circuits. [1][2][3][4][5][6][7] The conventional non-reciprocal optical devices are based on Faraday effect via an externally applied magnetic field in the direction of the propagation. However, the Faraday effect is weak in most magneto-optical (MO) materials [8] and a long optical path in the MO material is required for practical applications, which inherently limits the footprint of DOI: 10.1002/lpor.201900252 practical MO devices.…”

Magnetic field assisted transmission of THz waves through a graphene layer combined with a periodically perforated metallic film

“…Similar phenomenon -nonreciprocal phase shift 2,3 -takes place in asymmetric structures 4 (e.g., waveguides) when the direction of propagation is perpendicular to the magnetic field (Voigt geometry). These phenomena consitute the basis for the operation principles of a variety of microwave photonic devices, such as optical isolators 5,6 , circulators 7,8 , and switches 9,10 (for a review on practical application of magnetooptical materials see 11,12 ).…”

“…Appendix B: Transmittance of the graphene layer without periodical structure and the dispersion relation of magnetoplasmons When the metal film is absent (d = 0), then right-hand sides of Eqs. (5) and (12) become equal [as well as those of Eqs. (6) and (13)].…”

Optimized Magneto-optical Isolator Designs Inspired by Seedlayer-Free Terbium Iron Garnets with Opposite Chirality

“…Faraday rotation is a nonreciprocal rotation, or mode conversion, that occurs with a magnetic field parallel to the propagating light, and it can provide isolation together with a simple polarizer at the input of a waveguide 20,21 . Almost all of the recent devices in both categories have employed Ce:YIG as the MO material 8,19,[21][22][23][24][25][26] . In the first category, isolators based on Mach-Zehnder interferometers have been developed by bonding Ce:YIG onto Si-on-insulator (SOI) waveguides by surface-activated 18 or adhesive 22 bonding.…”