Electro-Optic Contact Poling of Polymer Waveguide Devices and Thin Films

Progressive Poling of Large Area, High r33 Electro-Optic Polymer SEO100c

“…In the test device the electrodes had 3 layers between them, a bottom cladding layer 4.3 µm thick of NOA 73, a 2.7 µm core layer of SEO 100c, and a top cladding layer 4.3 µm thick of NOA 73. The resistivities at 135 • C of NOA 73 and SEO 100c are known to be 3.3 × 10 10 Ωcm and 3.0 × 10 10 Ωcm, respectively [6]. Equation (1) shows how the voltage across the core layer of SEO100c was calculated.…”

“…where λ is the wavelength (1545 nm), d is the thickness of the core layer (2.7 µm), n is the index of refraction of the core (1.65) [6,13] and Γ is the overlap integral is 1 for vertically sandwiched electrodes because the entirety of the waveguide is covered by the uniform electric field. V core is the percentage of V π applied across the core layer, found to be 21% of the total field as described in Equation (1).…”

“…For EO polymers to obtain an r 33 , the chromophores must first be aligned through a poling process [6]. Poling involves heating the EO polymer structure to its glass transition temperature while applying a strong electric field across the EO polymer.…”

“…Poling involves heating the EO polymer structure to its glass transition temperature while applying a strong electric field across the EO polymer. Various methods of efficient poling to reach maximum r 33 while avoiding dielectric breakdown have been demonstrated including corona poling [7], and contact poling [6]. Corona poling is not used due to the need for voltages in excess of 3 kV, and non-uniform polling of EO-Layers [7].…”

“…This higher voltage introduces additional risks to the poling process as the high voltage may cause arcing between electrodes or cause a dielectric break down in any of the device layers. A preferred method to ensure maximization of r 33 for a wave-guiding device structure is to pole utilizing the mid-process poling technique [6]. Mid-process poling is performed after the core layer has been fabricated, allowing poling to be carried out on a partial stack of cladding-core layers, reducing the required applied voltage, and maximizing r 33 .…”