Magneto-optical devices

Introduction

Integrated nonreciprocal optical components are necessary for on-chip optical isolation and circulation. Different methods were proposed recently to substitute conventional magneto-optical bulk components [1]. One of the approaches is to exploit the Faraday effect for a nonreciprocal phase shift in the waveguides combined with a Mach–Zehnder interferometer [2]. Further miniaturization was proposed based on nonreciprocal disk resonators [3] and photonic crystal  resonators [4]. The proposed integrated concepts use epitaxially grown iron garnets. Up to 5500°/cm Faraday rotation was demonstrated in Ce and Bi comodified iron garnet (CeBiIG) epitaxial films [5]. The magneto-optical garnets are used as a core material of the slab or as a cladding material. These approaches involve structuring of the garnet or high-precision bonding. On the other hand, for non-garnet magneto-optical materials based on polymers, Verdet constants in the order of −10⁶ °/(Tm) at 1.55μm wavelength were demonstrated  recently [6-9]. These polymeric materials may allow a new class of nonreciprocal devices with magneto-optical cladding and can be combined with high-index waveguides in silicon (n=3.5). Apart from a simplified deposition, the cladding will also cover the sidewalls of the waveguides and will allow the use of TE-modes in ring resonators and photonic crystals. Another novel approach is to coat silicon structures with iron garnets with pulsed laser deposition [10]. Unfortunately the crystal structure of silicon and the silica is not compatible with the cerium and bismuth doped iron garnets (Ce:YIG, BIG) which exhibit a strong Faraday rotation. Therefore, yttrium iron garnet buffer layer is needed to successfully coat Ce:YIG and BIG layers onto silicon chips [11].

Goals

• Characterization of magneto-optical polymers on silicon waveguides
• Optical isolators and circulators at 1.55 µm wavelength in the micrometer scale

References

1.   Dötsch, H. et al. Applications of magneto-optical waveguides in integrated optics: review, J. Opt. Soc. Am. B 22, 240–253, (2005).

2.   Fujita, J., Levy, M., Osgood, R. M., JR., Wilkens, L. & Dotsch, H. Waveguide optical isolator based on Mach--Zehnder interferometer, Appl. Phys. Lett. 76, 2158–2160, (2000).

3.   Kono, N., Kakihara, K., Saitoh, K. & Koshiba, M. Nonreciprocal microresonators for the miniaturization of optical waveguide isolators, Opt. Express 15, 7737–7751, (2007).

4.   Wang, Z. & Fan, S. Optical circulators in two-dimensional magneto-optical photonic crystals, Opt. Lett. 30, 1989–1991, (2005).

5.   Sekhar, M. C. et al. Strong enhancement of the Faraday rotation in Ce and Bi comodified epitaxial iron garnet thin films, Appl. Phys. Lett. 94, 181916-3, (2009).

6.   Gangopadhyay, P. et al. Efficient Faraday rotation in conjugated polymers, Proc. SPIE 6331, 63310Z-5, (2006).

7.   Koeckelberghs, G. et al. Regioregularity in poly(3-alkoxythiophene)s: effects on the Faraday rotation and polymerization mechanism, Macromol. Rapid Comm. 27, 1920–1925, (2006).

8.   Gangopadhyay, P. et al. Faraday Rotation Measurements on Thin Films of Regioregular Alkyl-Substituted Polythiophene Derivatives, J. Phys. Chem. C 112, 8032–8037, (2008).

9.   Araoka, F., Abe, M., Yamamoto, T. & Takezoe, H. Large faraday rotation in a π-conjugated poly(arylene ethynylene) thin film, Appl. Phys. Express 2, 11501, (2009).

10. Bi, L. et al. On-chip optical isolation in monolithically integrated non-reciprocal optical resonators, Nat Photon 5, 758–762, (2011).

11. Wehlus, T., Körner, T., Leitenmeier, S., Heinrich, A. & Stritzker, B. Magneto-optical garnets for integrated optoelectronic devices, phys. stat. sol. (a) 208, 252–263, (2011).

Publikationen

• Jalas, D., Petrov, A.Yu, and Eich, M.: Theory of gyrotropic ring resonators with counterpropagating modes coupling Photonics and Nanostructures - Fundamentals and Applications, vol. 9(no. 4,): S. pp. 351–357, May 2011.
• Fan, S., Baets, R., Petrov, A., Yu, Z., Joannopoulos, J.D., Freude, W., Melloni, A., Popovic, M., Vanwolleghem, M., Jalas, D., Eich, M., Krause, M., Renner, H., Brinkmeyer, E., and Doerr, C.R.: Comment on "Nonreciprocal Light Propagation in a Silicon Photonic Circuit" Science, vol. 335( no. 6064): S. p. 38, January 2012.
• Petrov, A.; Jalas, D.; Eich, M.; Freude, W.; Fan, S.; Yu, Z.; Baets, R.; Popović, M.; Melloni, A.; Joannopoulos, J.D.; Vanwolleghem, M.; Doerr, C.R.; and Renner, H.: Comment on ”Linear and passive silicon optical isolator” Scientific Reports 2 , 674(ArXiv e-prints): S. pp. arXiv:1301.7243, January 2013.
• Jalas, D., Stepan, A., Petrov, A.Yu, and Eich, M.: Experimental demonstration of magneto-optical phase shift in silicon on insulator waveguides 8th IEEE International Conference on Group IV Photonics: IEEE: S. pp. 160–162, September 2011.
• Jalas, D.; Petrov, A.; Krause, M.; Hampe, J.; and Eich, M.: Integrated non reciprocal ring resonators Advanced Materials Research, vol. 216: S. pp. 533–538, March 2011.
• Jalas, D., Stepan, A., Petrov, A., Verbiest, T., Koeckelberghs, G., and Eich, M.: Nonreciprocal silicon-organic nanophotonic structures Proceedings of SPIE, vol. 8113: S. pp. 81130H, August 2011.
• Jalas, D.; Petrov, A.Y.; and Eich, M.; : Optical three-port circulators made with ring resonators Optics Letters, vol. 39(no. 6): S. pp. 1425–1428, May 2014.
• Jalas, D.; Petrov, A.Y.; and Eich, M.: Three port optical circulators with ring resonators Proc. SPIE, 9133: S. 913316, May 2014.
• Jalas, D.; Petrov, A.; Eich, M.; Freude, W.; Fan, S.; Yu, Z.; Baets, R.; Popovic, M.; Melloni, A.; Joannopoulos, J.D.; Vanwolleghem, M.; Doerr, C.R.; and Renner, H.: What is [mdash] and what is not [mdash] an optical isolator Nature Photonics, vol. 7(no. 8): S. pp. 579–582, July 2013.