.. I found time and will to put together laser diode driver, TEC controller, data conditioning circuitry and USB interface in one case. One of the DAC’s had been damaged when cleaning up the mess of circuits and loose wires, and the prospect of replacing that tiny SMD device (with the danger of making the whole PCB unusuable) had reduced my incentive to go on with this project since two years…well there were other reasons too. But it wasn’t that bad after all. So now everything works again and I go on developing a stable single mode red diode laser suitable for holography.
Next thing was to rebuild Colin’s laser head with extra emphasis on thermal stability. Just right now automated scans are performed for determining the best operating point (current and temperature). On the pic above you see the laser head in front of my universal diode controller incl digital measurement machinery.
I now also performed long term stability measurements, and posted the results on my revamped web site. After a few minutes warm-up time, the laser runs stable single mode without jumps for hours; the price is a moderate 32mW output compared to the 100mW+ the Rohm diode can do.