Operation of Broadband Isolators:

A broadband isolator achieves it wide bandwidth by compensating for the dispersion in the Faraday rotator optic. While the direction of polarization rotation in a Faraday rotator is dependent upon the direction of the rotators' magnetic field, the direction of rotation in a crystal quartz rotator is dependent upon the direction of light propogating through it. By using a 45° crystal quartz optical rotator with its dispersion similar to the optic in the Faraday rotator, and aligning the Faraday rotator and crystal quartz rotator such that they rotate the polarization of back reflected light in opposite directions, the Faraday isolator becomes less wavelength dependant. If 45° rotation at the center wavelength is used for both the Faraday rotator and crystal quartz rotator having the same dispersion, the net rotation will be 0° in the reverse direction and 90° (at the center wavelength only) in the forward direction. Figure 7 shows the effect of light traveling through a broadband isolator in the forward direction.

Figure 8 shows the effect of light traveling in the reverse direction through a broadband isolator.

• Introduction
  
• Operation of a Faraday Isolator
  
• Broadband Isolators for Ti:Sapphire and Other Tunable Lasers
  
• Operation of Broadband Isolators
  
• Dispersion in Ultrafast Ti:Sapphire Lasers; Sellmeiers Equation for TGG
  
• Key Optical Components of a Faraday Isolator
  
• Optical Component Specifications
  
• Isolation Defined
  
• Pulsed Damage Threshold; Root “T” Scaling