Diode Quantification

[danielbriggs]

A (low) powered test should be doable.
I cannot think of a good reason why it would not emit from the full width of the wafer edge; my understanding is the light will propagate through the entire waveguide. However; there is only one way to find out.

[kecked]

be very careful when you do it so you don't blow your ccd. You might want to use a filter or varibale polarizer to make sure you don't overload the camera. I did try this and it did not go well.

It is also possible that pre Iop the emitter will behave differently in terms of from where the laser emits. I have heard that the multimode diodes can run single mode up toa point before they go modal.

[andyf97]

A (low) powered test should be doable.
I cannot think of a good reason why it would not emit from the full width of the wafer edge; my understanding is the light will propagate through the entire waveguide. However; there is only one way to find out.

Indeed, while your going to the effort to measure them which is very appreciated, might be a good idea to run them and measure the actual emission width at the same time, the wafer width might not be that relevant if beam only comes out of 50%, I have no idea if it does or does not so it's worth to test this too especially on the larger emitter diodes. I guess nobody knows the answer to this for sure until its been tested.

Cheers

Andy

[danielbriggs]

I have just checked, and there are some fantastic diagrams in: Thompson - "Physics of Semiconductor Laser Devices".
He confirms the light emits from the full width junction, as thought.

[steve-o]

ML501P73 -
Emitter size: 98x2µm
ML520G71
Emitter size: 64x2µm

Well, F*ck. I thought that they were supposed to be the same. I thought hat was discussed in another thread earlier

[andyf97]

me too, i was even told this by a mitsubishi applications engineer. So glad i did not buy some hundreds.

[danielbriggs]

Just a point so far, I only have a sample size of 1...
Unlikely they would differ, but just saying these were from one supplier.

[planters]

Maybe just a coincidence, but the emitter size ratio is consistent with the rated power output ratio.

[danielbriggs]

Maybe just a coincidence, but the emitter size ratio is consistent with the rated power output ratio.

Nice observation.
I like it when things follow a rule. I wonder if output power could increase by the same factor as per the extra mileage on the G71's, keeping power density the same? We have an extra bond wire to play with, so you never know.

[planters]

Nice observation.
I like it when things follow a rule. I wonder if output power could increase by the same factor as per the extra mileage on the G71's, keeping power density the same? We have an extra bond wire to play with, so you never know.

I think this is a high likelihood. Same semiconductor. Same wavelength. Same manufacturer and the only reason the conductors were not increased by the NECESSARY 50% is that it was easier to add a second bond wire than to spec a 25% thicker one. As I had speculated earlier on in the G71 thread, the 73 diode is not better or worse its just bigger. Now if the net divergence is less than 50% worse then it is better, but maybe not enough to justify the substantial increase in cost. I think the uncertainty about the ultimate power handling ability of the two diodes will probably follow your speculation. The question is now more whether the optics will see the same ratio.