Semiconductor laser device

Abstract

Abstract PURPOSE:To improve single oscillation yield by forming a dielectric film, in which the reflectivity does not change from the one before the formation of a coating film and only the phase of light reflected by an end face changes, onto the coating film having low reflection. CONSTITUTION:A semiconductor laser device with a diffraction grating 4 is coated with an SiN film 7a and a metallic or dielectric multilayer film 8 and oscillation spectra are measured, and a dielectric film 9 is shaped onto the SiN film 7a in a semiconductor laser device not oscillated at a single longitudinal mode. An SiN film 9 composed of the same material is formed only by a film thickness section thinner than a quarter wavelength in the first layer of the dielectric film 9, thus elevating reflectivity, then displacing phase. An SiO2 film 9b and an Al2O3 film 9c are shaped onto the SiN film 9, and reflectivity is made the same as the beginning approximately and only phase is changed. Threshold gain difference is taken at a large value, thus allowing single mode oscillation.

Inventors

• 👤 Yasuo Nakajima
• 👤 康雄 中島

Bibliographic Details