Continue to Site

# relationship between VCSEL bias current and output power

#### mohamis288

##### Full Member level 2
Hi,
I am simulating a simple example for transferring data using optical components. please see the "image1" on the attachment. this is my main circuit. when I increased the bias current of VCSEL in "image2" from 5mA to 60mA , output power ended up to zero and oscilloscope does not shows anything( because of zero power). I do not know why, the output power diminished to zero by increasing the bias current?

#### Attachments

• image1.png
447.9 KB · Views: 76
• image2.png
468.2 KB · Views: 73
• image3.png
446.2 KB · Views: 72

Solution
Hi,
I am simulating a simple example for transferring data using optical components. please see the "image1" on the attachment. this is my main circuit. when I increased the bias current of VCSEL in "image2" from 5mA to 60mA , output power ended up to zero and oscilloscope does not shows anything( because of zero power). I do not know why, the output power diminished to zero by increasing the bias current?
in theory, increasing bias current always increase the output power. but as you know in real life, helpless VCSEL can not tolerate such high current and the output power. VCSEL will be going to be ruined. anyway, to simulate the VCSEL you must open the VCSEL laser property by double-clicking on the VCSEL object. after that, go...
Hi,
I am simulating a simple example for transferring data using optical components. please see the "image1" on the attachment. this is my main circuit. when I increased the bias current of VCSEL in "image2" from 5mA to 60mA , output power ended up to zero and oscilloscope does not shows anything( because of zero power). I do not know why, the output power diminished to zero by increasing the bias current?
in theory, increasing bias current always increase the output power. but as you know in real life, helpless VCSEL can not tolerate such high current and the output power. VCSEL will be going to be ruined. anyway, to simulate the VCSEL you must open the VCSEL laser property by double-clicking on the VCSEL object. after that, go to the "physical" tab and uncheck "thermal effect" to ignore the thermal effect. moreover, go to the "numerical" tab and uncheck "adaptive step".
CONGRATULATION!!
you can see the result successfully.

There's a bias current needed to keep it properly lit
(lasing threshold current) at the low end. At / below,
the beam may be incoherent.

Upward from there, efficiency climbs for a while so
power per watt climbs along with power.

Then series resistance and maybe some other inefficiencies
will roll on at higher currents, rolling d(output)/d(watt) down.
Power still climbs, less and less efficiently.

And then you fuse a bond wire and it's over. Though that
ought to take well more than 60mA.