On-Chip Electro-Optic Modulator With Loss Compensation Based on Polymeric Active-Integrated Waveguides

In this paper, an on-chip electro-optic (EO) modulator with loss compensation based on polymeric active-integrated waveguides was demonstrated. An erbium-doped waveguide amplifier was investigated and integrated with the EO modulator to compensate for signal loss. Polymeric active-integrated waveguides were based on the Mach-Zehnder interferometer structure, which consists of an amplified waveguide formed by two symmetric Y-junction branches and an EO waveguide formed by two decoupled waveguide arms. The dimensions of the polymeric active-integrated waveguides and the modulator were carefully designed and simulated. Moreover, a six-level spectroscopic model pumped at 980 nm was presented. The rate equations and propagation equations were solved, and the gain characteristics were simulated. The internal gain of 4.65 dB was achieved when the signal power was 0.1 mW at 1550 nm, the pump power was 100 mW at 980 nm, the Er
³⁺
concentration was $9.3\times 10^{25}/\text{m}^{3}$ , and the Yb
³⁺
concentration was $8.6\times 10^{26}/\text{m}^{3}$ in one Y-junction branch with a length of 1.5 cm. With the integrated waveguide amplifier, the loss of the EO modulator can be compensated at 9.3 dB in the two symmetric Y-junction branches. The light output intensity was also statistically presented. The proposed device with active-integrated waveguides could be used in polymer-based photonics integrated circuits.