Laser sources and laser interferometry with optical fibers

摘要

At present time the DFB (Distributed FeeBack), VCSEL (Vertical Cavity Surface Emitting Laser) and FBG (Fiber Bragg Grating) based laser diodes are suitable like laser source for using in laser interferometry. Their linewidth of the emission spectrum and the mode-hop free tuning range of the wavelength are crucial parameters for laser sources in laser interferometry, especially absolute laser interferometry. We present our set-up of the fiber laser interferometer where these laser diodes can be used. The design of the optical set-up of the experimental interferometer is realized using fiber optics to reduce the influence of the index of refraction of air. The measurement probe was realized by standard optical fiber with reflection coated optical connector. Our primary wavelength of this laser interferometer is 760 run. We used the DFB laser diode at 760 run wavelength with mode-hop free tuning range above 1 nm and fiber output up to 10 mW. We present our first characteristics without external stabilization of the output wavelength. We compared our new DFB laser source with our previously developed laser source with VCSEL diode and with FBG based laser diodes. On the basis of our simulations and measurements of the commercially available fiber gratings we designed a special 100 mm long fiber Bragg grating with apodization. Finally, we simulated required parameters of fiber gratings arrays for laser interferometry - multiple fiber gratings. Results are presented.