A key component of the OCT technique is the light source with widely spectrum. Extremely broadband 1.0 μm
semiconductor light sources are fabricated with two kinds of device structures of multiplexing emitting layer. The
measured spectra of the fabricated device with "longitudinal bandgap modulated structure" show that the full-width at half-maximum spectral width could be as large as 156 nm. The wavelength swept sources which contain a fabricated device with "asymmetric dual emitting layers structure" have a center wavelength of 1.06 μm, wavelength range of 90 nm, scanning rate of 2kHz.