Skip to main content
Solved

Adding a free space isolator to a Zemax simulation


Forum|alt.badge.img
  • Single Emitter
  • 1 reply

Has anyone had experience adding a free space isolator to a Zemax simulation?

Best answer by David

Hello RRG,

I have not designed an isolator before, but I have used OpticStudio to design retarders. I attach two non-sequential zar files which are perhaps a starting point.

“Quarter wave plate” determines the thickness of birefringent quartz necessary to make a quarter wave retarder. It’s at 550nm, but could be re-optimized for another wavelength.

“Isolator 1_0” uses that quartz thickness. A Source Ellipse launches 1000 rays with random polarization. They go through a polarizer which consists of a Jones Matrix embedded in a window of N-BK7. They then pass through the QWP and strike a window of N-BK7 which represents downstream optics from which we want isolation. Rays that reflect back go through the QWP again and are killed by the polarizer. The polarizer and QWP are AR coated. (The coating could be improved.) There are detectors which measure transmitted and reflected power.

As designed, the reflected detector receives 2.3%. If the QWP is set to Ignore and Hide the reflection increases to 5.7%.  The as-designed reflection could be reduced by improving the AR on the  polarizer and QWP. Path Analysis can be used to explore reflections in detail.

 

 

View original
Did this topic help you find an answer to your question?

2 replies

David
Luminary
Forum|alt.badge.img+4
  • Luminary
  • 336 replies
  • Answer
  • March 12, 2022

Hello RRG,

I have not designed an isolator before, but I have used OpticStudio to design retarders. I attach two non-sequential zar files which are perhaps a starting point.

“Quarter wave plate” determines the thickness of birefringent quartz necessary to make a quarter wave retarder. It’s at 550nm, but could be re-optimized for another wavelength.

“Isolator 1_0” uses that quartz thickness. A Source Ellipse launches 1000 rays with random polarization. They go through a polarizer which consists of a Jones Matrix embedded in a window of N-BK7. They then pass through the QWP and strike a window of N-BK7 which represents downstream optics from which we want isolation. Rays that reflect back go through the QWP again and are killed by the polarizer. The polarizer and QWP are AR coated. (The coating could be improved.) There are detectors which measure transmitted and reflected power.

As designed, the reflected detector receives 2.3%. If the QWP is set to Ignore and Hide the reflection increases to 5.7%.  The as-designed reflection could be reduced by improving the AR on the  polarizer and QWP. Path Analysis can be used to explore reflections in detail.

 

 


Forum|alt.badge.img
  • Author
  • Single Emitter
  • 1 reply
  • March 15, 2022

Dear David,

 

Thanks so much for you thoughtful reply. I shall take a close look at the sample you provided as a possible guide for my work. Thanks again!

 

RRG


Cookie policy

We use cookies to enhance and personalize your experience. If you accept you agree to our full cookie policy. Learn more about our cookies.

 
Cookie settings