ITO-assisted fiber-optic polarization-insensitive electro-absorption optical modulator

The identical modulating ability between transverse electric, TE, and transverse magnetic, TM, modes is stringent condition while realizing polarization insensitive optical modulators. This in turn incorporates significant compromise in polarization sensitive loss, PSL. In this work, we propose the concept of fiber-optic polarization-insensitive optical modulator architecture that is attributed with a microscale length and low PSL. This is achieved by transferring Al/HfO2/ITO/HfO2 stack around the core region of half polished fiber that imposes equal influence on the horizontal and vertical components of propagating optical modes. Moreover, the majority of propagating optical modes is concentrated around active material region that results in compact, enhanced modulator design. The modulator is capable of offering extinction ratio as high as 23.71 dB and insertion loss as low as 1.01 dB for the TE mode. Concurrently, for TM mode are 23.93 dB and 1.07 dB. The PSL at ON-State of ∼0.056 dB ensures similar modulating ability for both TE and TM modes. The 3 dB modulating bandwidth of 45.85 GHz is realized with active length of 10 μm at the expense of 0.39 pJ/bit. The operating wavelength ranges between ∼1475 nm and ∼1625 nm with optical bandwidth excess of 150 nm.