Green multi-SLED source for high-resolution visible OCT

We demonstrate the first broadband light source based on spectral combination of four superluminescent diodes (SLEDs) in the cyan-to-green wavelength range, suitable for high-resolution, visible optical coherence tomography (OCT). Two integrated combined-SLED sources, each comprising two wavelength-shifted green SLEDs, are realized through micro-optical module integration. Each of those two combined-SLED sources is delivering a highly polarized output spectrum at a polarization-maintaining (PM) fiber. The output of the two PM fibers is then spectrally combined with a free-space, micro-optical combiner module to a common, single-mode fiber output with a broadband output spectrum having a 10dB wavelength range from 481nm to 519nm, a 3dB bandwidth of 32nm and a coherence length of 4.5 microns in air.