Cost-effective optical coherence tomography spectrometer based on a tilted fiber Bragg grating

Abstract

A compact, fiber-based spectrometer for biomedical application utilizing a tilted fiber Bragg grating (TFBG) as integrated dispersive element is demonstrated. Based on a 45° UV-written PS750 TFBG a refractive spectrometer with 2.06 radiant/µm dispersion and a numerical aperture of 0.1 was set up and tested as integrated detector for an optical coherence tomography (OCT) system. Featuring a 23 mm long active region at the fiber the spectrum is projected via a cylindrical lens for vertical beam collimation and focused by an achromatic doublet onto the detector array. Covering 740 nm to 860 nm the spectrometer was optically connected to a broadband white light interferometer and a wide field scan head and electronically to an acquisition and control computer. Tomograms of ophthalmic and dermal samples obtained by the frequency domain OCT-system were obtained achieving 2.84 µm axial and 7.6 µm lateral resolution.

Upper airway reconstruction using long‐range optical coherence tomography: Effects of airway curvature on airflow resistance

“…Sedation may be avoided with stand‐alone use of the LR‐OCT device. However, imaging in awake children can become challenging as the probe becomes bigger with the need for tracking, and may require the use of fiber Bragg grating . As noted by Lazarow et al one of the limitations of the present study was anatomic distortion of the airway reconstructions owing to sedation and ET tube presence.…”

Highly Efficient Optical Beam Steering Using an In-Fiber Diffraction Grating for Full Duplex Indoor Optical Wireless Communication

“…Without cylindrically symmetric grating structures in a 45° TFG, lateral diffraction is highly polarization dependent [27], making it a perfect in-line fiber polarizer [19]. 45° TFGs have also found rich applications in optical spectrum analysis [28], mode-locked lasers [29], Fourier-domain optical coherence tomography [30], wavelength-encoded imaging [31], and ultrafast photonic time-stretch imaging [32][33]. Here, we present the first comprehensive study and experimental demonstration of using a 45° TFG as a highly efficient in-fiber diffraction device for wavelength-controlled passive optical beam steering.…”

Numerical and Experimental Characterization of Radiation Mode of 45° Tilted Fiber Grating

“…On the other hand, the radiation mode has also attracted much attention. So far, 45° TFG has been successfully applied as a key element to separate polychromatic light into monochromatic components in optical spectrum analyzer, wireless optical communication system, spectrally encoded imaging system, ultrafast photonic time-stretch imaging system and Fourier-domain optical coherence tomography (OCT) spectrometer [16]- [19]. However, different from the traditional volume diffraction gratings, the spatial distributions of the radiation mode of a uniform 45° TFG have several inherent flaws, such as the asymmetrical energy distributions and the large divergence angle.…”