saturation energy of soa

Vipul Hi,
After going through tutorials you are unable to figure out, how saturation energy in SOA is calculated. In the quoted tutorial the parameters of SOA saturation energy comes out to be 3.7PJ. The formula for calculation of saturation energy in SOA is:
Esat = hv σm / σd

σd the gain cross section, the differential gain
h is planck’s constant
σm = w d / Γ the cross-section area of the wave-guide mode
Γ – the confinement factor
w – width of SOA
d – thickness
You need to refer some standard text book on SEMICONDUCTOR OPTICAL AMPLIFIER to understand it completely.
Regards.

Hi Vipul,

First, I would recommend you to read the detailed answer of Rk Sethi (which is basically answers your question). From myself I would just like to add that in most of design cases in practice we are dealing with the saturation input power which is the output optical power at which the amplifier gain decreases by a factor of two (or by 3 dB). For your further understanding, I am attaching you a short overview about SOA from Cornell University, which is in a free access online.

Hi Ravil and RK sethi,in optisystem SOA model there is input facet reflectivity and output facet reflectivity is 0.Is it possible in practical SOA,s? As as far as reflectivity of SOA is concerned it may be reduced to min but can not be zero.Correct me if i am wrong somewhere.

Hi Sam Sung,

I agree with your point of view and don’t think that it is practically possible to make the reflectivity to be equal exactly zero. However, it is known that it can be reduced to some negligible value (is this what that “0” mean?). Dear Optiwave Team, please, let us know under what conditions such reflectivity is possible…

Thank you Ravil,I have read many articles that faet reflectivity can be reduced by tilted active region or by doing anti reflective coatings. But achieving 0 value is ,i think no practical.may be Damian give this answer better.

You are welcome, Sam Sung! The exact “0” is not achievable due to known physical reasons. However, please, take a look at Damian’s comment. He has highlighted a very interesting point. Thank you for your answer, Damian!

Thankyou for clearing my doubt too!!
I am also using SOA with 0 facet reflectivity in my system setup for all optical t and d flip flop. and have been asked same question.
I also took is as a reference from an article

Thank you Damian for explaining this concept of SOA facet reflectivity.As i am working on the SOA non linearity and applications.Most important point is ,the paper you have given is clearly shows that tn can be possible to achieve value close to zero.So this will work as strong point me to prove,who soever may ask me question about this.
Also tank you Ravil as you also supported my query,you are very helpful too 🙂