Manufacturing and characterization of integrated optical phase-shift interferometer

Optical interferometers are key devices in constructing aperture synthesis telescope. Compared with optical interferometers implemented with conventional discrete elements, integrated optical phase-shift interferometers possess ultra-compact structure, and thus can be applied in aperture synthesis telescope to optimize its structure and improve its stability as well. Silica based integrated optical phase-shift interferometer was studied, in aspects of its design, fabrication, as well as its characterization. Results show that the two direction couplers in interferometer chip possess well consistency in terms of their coupling efficiency, thanks to integrated optical waveguide technology itself. Excess loss of interferometer chip was measured to be as low as 1.8 dB, with uniformity of 0.1 dB. Phase shift error was estimated by measuring MZ interferometers, and results exhibit that error of 90 phase shifter is approximately 1.5 . Analysis show that silica based waveguide technology is promising in fabrication of optical phase-shift interferometers utilized in aperture synthesis telescope.