Patent ID: 7554668

Claim:
A swept source OCT system comprising: a tunable light source; a beam splitter for dividing the light along a sample and a reference path; a photodetector for receiving light returned from both the sample and the reference paths and generating output signals as a function of time as the wavelength of the source is tuned; a processor for analyzing the output signals to derive a reflectance distribution along the sample path and wherein the tunable light source includes an elongated optical waveguide structure, with one end thereof defining a laser output facet; a linear series of distributed feedback gratings formed along the waveguide structure to define a series of resonant cavities; a series of semiconductor gain structures formed within the waveguide structure and aligned with the gratings, with the bandgap energy of the gain structures increasing towards said output facet; and a power supply for supplying current to the gratings and the gain structures in a manner to generate laser output from each resonant cavity and for wavelength tuning the output.