Towards the improvement of attenuation range and response time of electrochromic polymer-based variable optical attenuators

Abstract A solid–liquid electrochromic variable optical attenuator device consisting of a thin layer of LiClO4-doped poly(3,4-ethylenedioxythiophene) (PEDOT) and ferrocene in propylene carbonate has been demonstrated to exhibit a large dynamic range of optical attenuation at the telecommunication wavelength of 1550 nm. Doping of PEDOT film with an electrolyte greatly improves the device performance in terms of optical attenuation or color efficiency at 1550 nm and response time. An optimized single-layer device consisting of LiClO4-doped PEDOT film (440 nm) shows a 10-dB dynamic range of optical attenuation at 1550 nm, a low optical loss of 0.86 dB for the bleached state, and a response time of 5–7 s at the switching potential of 0–2 V.