A polarization-maintaining buffered Fourier domain mode-locked (FDML) swept source with a center wavelength of 1300 nm is demonstrated. The scanning rate of the buffered FDML swept source is doubled without sacrificing the output power of the swept source by combining two orthogonally polarized outputs with a polarization beam combiner. The stability of the swept source is improved because the polarization state of the laser beam inside the laser cavity is maintained without the use of any polarization controllers. The swept source is capable of an edge-to-edge tuning range of more than 150 nm and a FWHM range of 95 nm at a 102 kHz sweeping rate and with an average power of 12 mW. A swept source optical coherence tomography (SSOCT) system is developed utilizing this buffered FDML swept source. The axial resolution of the SSOCT system is measured to be 9.4 µm in air. The sensitivity of the SSOCT system is 107.5 dB at a depth of 0.25 mm with a 6 dB roll-off at a depth of 2.25 mm.

Multiple light scattering is considered as the major limitation for deep imaging and focusing in turbid media. In this paper, we present an innovative method to overcome this limitation and enhance the delivery of light energy ultra-deep into turbid media with significant improvement in focusing. Our method is based on a wide-field reflection matrix optical coherence tomography (RM-OCT). The time-reversal decomposition of the RM is calibrated with the Tikhonov regularization parameter in order to get more accurate reversal results deep inside the scattering sample. We propose a concept named model energy matrix, which provides a direct mapping of light energy distribution inside the scattering sample. To the best of our knowledge, it is the first time that a method to measure and quantify the distribution of beam intensity inside a scattering sample is demonstrated. By employing the inversion of RM to find the matched wavefront and shaping with a phase-only spatial light modulator, we succeeded in both focusing a beam deep (~9.6 times of scattering mean free path, SMFP) inside the sample and increasing the delivery of light energy by an order of magnitude at an ultra-deep (~14.4 SMFP) position. This technique provides a powerful tool to understand the propagation of photon in a scattering medium and opens a new way to focus light inside biological tissues.

We demonstrate a high-speed and wide-tuning-range swept laser for optical coherence tomography (OCT) imaging. The repetition rate of the laser is twice the speed of the polygon filter and is achieved by using two delay fibers in a Fox-Smith cavity. The performance of the laser is the following: a scanning range of 110nm centered at 1310nm, and the output power of 10mw at a 102.2 kHz sweeping rate. © 2011 Copyright SPIE - The International Society for Optical Engineering.

A polarization maintaining buffered Fourier domain mode-locked (FDML) swept source at center wavelength of 1310 nm for multiplying the scanning rate of FDML swept source was demonstrated. The scanning rate of the buffered FDML swept source was doubled without sacrificing the output power of the swept source by combining two orthogonally polarized outputs with a polarization beam combiner (PBC). The stability of the swept source was improved significantly because the polarization state of the laser beam inside the cavity is maintained without any polarization controllers. With the linear polarization states of the output laser beam, the buffered FDML swept source is also ready to be used in a PSOCT system. The swept source is capable of a tuning range of more than 150 nm at a 102 kHz sweeping rate. An FDOCT system was developed with the built swept source. © 2012 SPIE.