Hi Chandan,

X-Divergence and Y-Divergence are not strictly the beam divergence angles. They are parameters of a Gaussian or super Gaussian distribution. The distribution is Gaussian if the SuperGauss value is 1. In this case, the divergence values are the angles in degrees at which the Gaussian beam intensity falls to 1/e^2 of its maximum intensity on the respective axis.  So this is a half angle. From the help file on Source Diode:

The help entry has information relating these parameters to FWHM beam divergence.

It appears to me that what you wish to model is a pair of laser diodes on one die. The separation of the two diodes appears to be 225 um center-to-center. This is the delta-x value if number of diodes in the array is given as 2 in the x dimension and 1 in the y dimension, as above.

r Hi Chandan,

X-Divergence and Y-Divergence are not strictly the beam divergence angles. They are parameters of a Gaussian or super Gaussian distribution. The distribution is Gaussian if the SuperGauss value is 1. In this case, the divergence values are the angles in degrees at which the Gaussian beam intensity falls to 1/e^2 of its maximum intensity on the respective axis.  So this is a half angle. From the help file on Source Diode:

 

The help entry has information relating these parameters to FWHM beam divergence.

It appears to me that what you wish to model is a pair of laser diodes on one die. The separation of the two diodes appears to be 225 um center-to-center. This is the delta-x value if number of diodes in the array is given as 2 in the x dimension and 1 in the y dimension, as above.

Dear David,

Thanks for your reply.

I am attaching the emission pattern of laser diode that I want to simulate…

As far as I understood based on the above discussion, I have to enter 33 degree in “X - divergence” if I am cosidering x direction as gaussian divergence perpendicular to the junction.  Am I right? 

Regards,

Chandan Maurya

Hi Chandan,

From the graph it appears that 33 degrees is the 1/e^2 half angle, if so then that is correct. I assume that is the 33 entered in the table, but the table as shown does not have column labels.

Also, there is something misleading in my answer above. The divergence parameters give the 1/e^2 angle in degrees regardless of the values of the super-Gaussian (Gx, Gy). However, the formula for FWHM given in the help entry would change for values of Gx, Gy other than 1.

Dear David,

Thanks for inputs, now I have clear idea about X,Y- Divegence.

In above post I didn’t recognize that columns lables are not there. Extremly sorry for that, here I am attaching for your reference.

Regards,

Chandan

Thanks, Chandon. I still remain a bit uncertain. From the graph it appears 33 degrees is the 1/e^2 half angle. But in the table I see a test condition of FWHM. Does the spec say clearly how the 33 degrees is measured?

Dear David,

No, they are not discussing the measurements process.