Wouter Van Parys

Transverse magnetic mode nonreciprocal propagation in an amplifying AlGaInAs∕InP optical waveguide isolator

The design, fabrication, and characterization of an amplifying transverse magnetic (TM)-mode optical waveguide isolator operating at a wavelength of 1300nm are presented. The magneto-optical Kerr effect induces nonreciprocal modal absorption in a semiconductor optical amplifier with a laterally magnetized ferromagnetic metal contact. Current injection in the active structure compensates for the loss in the forward propagation direction. Monolithic integration of this optical isolator configuration with active InP-based photonic devices is straightforward. The combination of AlGaInAs∕InP active material and the metal alloy Co50Fe50 results in greatly improved performance. 99dB∕cm TM mode isolation and significantly reduced insertion loss are demonstrated.

Experimental demonstration of nonreciprocal amplified spontaneous emission in a CoFe clad semiconductor optical amplifier for use as an integrated optical isolator

Experimental results are presented for an integrated-optical-waveguide-isolator concept. This concept is based on inducing the transverse magneto-optic Kerr effect in a semiconductor InP-based optical amplifier (SOA) by using a transversely magnetized ferromagnetic metal as an electrical contact. As a result, the SOA exhibits nonreciprocal loss/gain for TM polarized light and is easily monolithically integrated with other InP-based active photonic devices. We have designed, fabricated and characterized prototype ferromagnetic metal-clad optical amplifiers for an operation wavelength of 1300nm. In these first generation devices we obtained isolation strengths of up to 2.0dB∕mm.

Design and optimization of a monolithically integratable InP-based optical waveguide isolator

The optimization design of the layer structure for a novel type of a 1.3 μm monolithically integrated InP-based optical waveguide isolator is presented. The concept of this component is based on introducing a nonreciprocal loss-gain behavior in a standard semiconductor optical amplifier (SOA) structure by contacting the SOA with a transversely magnetized ferromagnetic metal contact, sufficiently close to the guiding and amplifying core of the SOA. The thus induced nonreciprocal complex transverse Kerr shift on the effective index of the guided TM modes, combined with a proper current injection, allows for forward transparency and backward optical extinction. We introduce two different optimization criteria for finding the optimal SOA layer structure, using two different figure-of-merit functions (FoM) for the device performance. The device performance is also compared for three different compositions of the CoxFe1−x(x=0,50,90) ferromagnetic transition metal alloy system. It is found that equiatomic (or quasi-equiatomic) CoFe alloys are the most suitable for this application. Depending on the used FoM, two technologically practical designs are proposed for a truly monolithically integrated optical waveguide isolator. It is also shown that these designs are robust with respect to variations in layer thicknesses and wavelength. Finally, we have derived an analytical expression that gives a better insight in the limit performance of a ferromagnetic metal-clad SOA-isolator in terms of metal parameters.

11.4 dB isolation on an amplifying AlGaInAs/InP optical waveguide isolator

11.4 dB optical isolation combined with forward transparency is demonstrated on a TM-mode amplifying AlGaInAs/InP optical waveguide isolator operating at 1300 nm. Basis for this isolator configuration is non-reciprocal absorption caused by the magneto-optic Kerr effect

Magneto-optic Contact for Application in an Amplifying Waveguide Optical Isolator

We present the development of a metal-semiconductor contact for a TM-mode amplifying waveguide optical isolator and show that it is a compromise between good (magneto-)optical performance and good electrical behavior