Abstract
We have proposed, simulated, fabricated and experimentally demonstrated monolithically integrable semiconductor active waveguide optical isolators based on the nonreciprocal loss at an optical telecommunication wavelength range of 1530-1560nm. The semiconductor active waveguide optical isolators are composed of semiconductor optical amplifier (SOA) waveguides and ferromagnetic metals. In transverse electric (TE) mode semiconductor active waveguide optical isolators composed of InGaAsP SOA waveguides and Fe thin films, we demonstrated 14.7dB/mm optical isolation at the wavelength of 1550nm and 10dB/mm isolation over entire wavelength range of 1530-1560nm. In transverse magnetic (TM) mode semiconductor active waveguide optical isolators, we used epitaxially grown MnAs thin films as top ferromagnetic electrodes, and demonstrated stable electrode performance and 8.8dB/mm optical isolation. Based on these demonstrations, we can realize monolithic integration of optical isolators with edge-emitting semiconductor laser diodes and polarization insensitive semiconductor active optical isolators. We also discussed the problems and solutions of our semiconductor active waveguide optical isolators at present stage.
