The ETMY laser was operating at 1.5 A current and 197 mW power.
For the efficient frequency doubling of the AUX laser beam at the ETMY table, a higher power is required.
Steve and I changed the current level of the laser from 1.5 A to 2.1 A in steps of 0.1 A and noted the corresponding power output . The graph is attached here.
The laser has been set to current 1.8 Amperes. At this current, the power of the output beam just near the laser output is measured to be 390 mW.
The power of the beam which is being coupled into the optical fibre is measured to be between 159 mW to 164 mW (The power meter was showing fluctuating readings).
The power out of the beam coming out of the fibre far-end at the PSL table is measured to be 72 mW. Here, I have attached a picture of the beam paths of the ETMY table with the beams labelled with their respective powers.
Next we are going to adjust the green alignment on the ETMY and then measure the power of the beam.
At the output end of the fibre on the PSL, a power meter has been put to dump the beam for now as well as to help with the alignment at the ETMY table.
For the phase locking or beat note measuring we only need ~1 mW. Its a bad idea to send so much power into the fiber because of SBS and safety. The power should be lowered until the output at the PSL is < 2 mW. In terms of SNR, there's no advantage to use such high powers.
Well,the plan is to put in a neutral density filter in the beam path before it enters the fibre. But before I could do that, I set up the camera on the PSL table to look at the fiber output . I will need it while I realign the beam after putting in the Neutral Density Filter. I have attached the ETMY layout with the Neutral Density filter in place herewith.
1.5 days of happy psl-ioo with litle bumps in C1:PSL-126MOPA_HTEMP