Electro-Optic Light Modulators

If you already read in the last section “The Electro-Optic Effect” or, more specifically, the subsection “Electro-Optic Modulation” then you already basically know the workings of an electro-optic modulator. If you have not already read through that section, then I would recommend you do so now as we will be only going over some of the results in this section. We will expand on our previous lessons and look at longitudinal vs transverse modulators.

Table of Contents:

  1. Longitudinal Electro-Optic Modulation
  2. Transverse Electro-Optic Modulation


As can be seen in the figure below, longitudinal electro-optic modulators have the voltages applied parallel to the direction of the light beam; as such, in order to increase the delay, higher voltages must be used. This, then, is one of the main problems with the longitudinal electro-optic modulator: high voltages are required. The voltages for longitudinal electro-optic modulators can in fact reach up to the multi-kV range. One of the main advantages of the longitudinal configuration, though, is that the modulators can have a wide acceptance aperature, so the confinements on needing a well-defined beam (i.e. well collimated) are not as strict. The main applications of longitudinal electro-optic modulators is in applications that do not require a high frequency response, or in non-laser applications.

Course 4, Module 7: Electro-Optic and Acousto-Optic Devices


Free-Space Electro-Optic Modulators
%d bloggers like this: