THORLABS OCT-LK2(-BB), Руководство пользователя

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OCTG Series Scanner Chapter 5: Description
Page 10 MTN004419-D02
5.2. Optical Design
5.2.1. Common Path Setup
As shown below in Figure 1, in this configuration, the scanner is factory-configured such that the sample
beam and reference beam are generated after the beam leaves the fiber. This allows you to use single-mode
optical fiber to transport the beam into the scanner while minimizing the use of free-space propagation.
This approach avoids problems that can degrade image quality, related to optical phenomena like polarization
mode dispersion (PMD) and birefringence, and makes the performance of the system independent from the
length of the single-mode fiber.
Figure 5 Diagram of the Common Path Setup
5.2.2. Dual Path Setup (OCTG-NR)
Shown below in Figure 6 is the beam geometry when the scanner is ordered in a special configuration without
reference. The sample beam and reference beam are generated within different fibers, before the beam exits
into free space. In this configuration, the scanner becomes the sample arm of the interferometer. By using
two different fibers, the beamsplitter cube used in the Common Path Setup is no longer needed.
This configuration allows single mode optical fiber to be used to a greater extent within the setup. While this
approach is able to provide greater sensitivity due to the absence of the beamsplitter cube (which reduces
the intensity of the light that returns to the fiber), it is significantly more sensitive to the optical phenomena
mentioned before. Please contact
Thorlabs’ OCT support (see Chapter 11) for details.
Figure 6 Diagram of the Dual Path Setup