Magneto-optical waveguide isolator with 104 dB/cm non-reciprocal propagation

摘要: Optical isolators protect active devices (i.e. lasers) from optical feedback. All research in the past focused on transmission of light through ferromagnetic garnets [1] with low loss at telecom wavelengths and strong magneto-optical (MO) Faraday effects. The monolithic integration III-V host materials would greatly reduce cost a laser diode package by avoiding accurate alignment needed an external isolator. best reported result based bonding shows isolation ratio only 5dB [2]. A novel concept for – transversal magnetic mode (TM) isolator semiconductor amplifier (SOA) contact was proposed [3] demonstrated us [4]. Lateral magnetization induces non-reciprocal shift refractive index TM guided modes, due to MO Kerr effect. propagation losses can be compensated electrical pumping SOA contact. Fig. 1a illustrates device structure 1b operation principle. AlGaInAs-based multi-quantum well (MQW) layer built-in tensile strain has been developed [5] TM-selective gain 1.3μm wavelength. sputter-deposited 50 nm thick Co50Fe50 film patterned into 3.5 μm wide stripes lift-off serves as etch mask define ridge waveguides. 1c hysteresis measured looping field change FM while measuring amplified spontaneous emission SOA. strength extracted transmitted power both lateral directions is 104dB/cm.