Optical transmission using super luminosity LEDs as a transmitter and a receiver

Recently, technologies of super luminosity LEDs make rapid progress and visible blight LEDs are now commercially available. In this paper, we investigate to clarify the potential and limitation of super luminosky LEDs for optical transmission applications. Both sending and receiving properties are measured, such as baseband frequency response of direct modulation, wavelength dependences of responsivity. The peak wavelength of emission power and the peak wavelength of responsivity are measured. The interesting phenomenon is found that the two peak wavelengths are different and the peak detection wavelength is shifted to shorter wavelength when compared to the emission peak wavelength. This phenomenon occurs in measured all LEDs and also in laser diodes. Using a simple model, this short wavelength shift is explained. Basic optical transmission experiments using super luminosity LEDs as a transmitter and a receiver are constructed to confirm the photo-detection properties of super luminosity LEDs. We also discuss possible applications of super luminosity LEDs in optical transmission systems.