Light coupling from a stripe‐geometry GaAs diode laser into an optical fiber with spherical end

The acceptance angle of a fiber is increased remarkably by forming the fiber end spherically. It was demonstrated with light coupling into a fused‐silica‐core glass fiber from a mesa‐stripe‐geometry GaAs diode laser. The coupling efficiency increased in this way is observed to be 5.2 times as high as that of a previous method. The proper design of a fiber in this manner will lead to a light coupling efficiency higher than 90%.