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* [https://wiki.physics.wisc.edu/yavuz/images/7/7a/Laser_Tuning_Circuit.pdf Wide Tune Laser Write-Up]
* [https://wiki.physics.wisc.edu/yavuz/images/3/3d/VCO_integrating_circuit.pdf VCO Integrator]
===ECDL Tuning===
'''8/17/15'''
The 1055nm laser does not work well with the ramp set at high ratios so the optimal ratio of 10 mA/V definitely didn't work. I tried a few scans with a ratio of about .07mA/V which is closer to what I used for the 785 laser and it scanned much larger ranges of about 8GHz. Right now the ratios between .12-.17mA/V have produced scans over the whole 0-150V piezo range without mode hops with the laser tuning about 18 GHz. These scans were tried with setpoints of 70,74, 78 mA on the diode driver and all gave similar tuning ranges. The 78 mA setpoint tunes over a a range that is a little offcenter to lower frequencies from the 1055.076nm center (-6-12GHZ). The lower setpoints seems to scan over a different mode and tunes the laser offcenter to higher frequencies from center (-10-8GHz). I think the only way to center the tuning range more is to adjust the horizontal setting of the grating.
'''8/5/15'''
I was able to achieve 20-25GHz tuning range with the 785 nm diode with a ratio of about -.1mA/V. The best scans were with the current at a setpoint between 80-100mA. Through each scan, the current dropped about 15 mA which led to a drop in output power of about 8-9mW. With the 1055nm diode, I got the tuning rates for the piezo to be .14GHz/V. The current tuned extremely slow with about .0134GHz/mA. Using these rates, the ratio for the current and piezo should be 10.45mA/V.
'''7/16/15'''
I tuned the laser by varying the current from 35mA to 120mA and kept the piezo at 2V for one scan and 35V for another. The 2V scan gave a little cleaner data and both gave nearly the same tuning rate of about -1.5 GHz/mA. The rate seemed to increase at higher currents. This tuning rate along with the piezo tuning rate implies that the piezo and current should be tuned with a ratio of about -.107 mA/V which is quite low compared to what I've been reading.
'''7/14/15'''
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