LASER-DIODE WAVELENGTH TUNING BASED ON BUTT COUPLING INTO AN OPTICAL-FIBER

An extremely short external cavity that is realized when a Fabry-Perot laser diode is butt coupled to a waveguide or a fiber produces feedba ck that is effective for controlled wavelength tuning. We used butt co upling to tune a high-output-power laser diode over a wide range (as g reat as 15 nm) while maintaining constant driving current and temperat ure. Single-mode or multimode operation repeatedly occurred at specifi c points throughout the tuning range. An analytical model that include s the effect of multiple reflections from the external cavity, each at tenuated by a modal overlap integral, and which is based on phenomenol ogical principles, shows good agreement with the experimental results. (C) 1997 Optical Society of America.