I recorded the thermistor (temperature) values that I used for the OPO nonlinear gain measurement.
Initially I searched in increments of +/- 0.01 kOhm on the thermistor, and then checked a bit within the optimal range. Perhaps there is further room for optimisation when zooming in on the oscilloscope though. At 100 mV/div ranges on the oscilloscope, the difference in voltage for thermistor change under 0.01 kOhm was hard to distinguish.
In the table I give the temperature, oscilloscope reading as well as the range value on the power meter - using a range of 1.6 mW on the power meter gives 10x more voltage on the oscilloscope than a range of 16 mW.
| green power [mW] | 0 | 10 | 15 | 20 | 25 | 30 | 35 | 40 | 50 | 60 |
| MZ offset | 3.9 | 4.0 | 4.1 | 4.2 | 4.3 | 4.4 | 4.5 | 4.7 | 4.9 | |
|
Amplification reading [mV] (power meter range [mW]) |
456 (1.6) | 1140 (1.6) | 1710 (1.6) | 234 (16) | 308 (16) | 408 (16) | 578 (16) | 816 (16) | ||
| De-amplification reading [mV] (power meter range [mW]) | 456 (1.6) | 240 (1.6) | 216 (1.6) | 192 (1.6) | 178 (1.6) | 166 (1.6) | 160 (1.6) | 152 (1.6) | ||
| Thermistor value [kOhm] | 7.137 | 7.147 | 7.165 | 7.173 | 7.185 | 7.196 | 7.203 | 7.215 | 7.215 | 7.225 |
| p pol PLL frequency [MHz] | 190 | 180 | 195 | 190 | 200 | 205 | 200 | 205 | 185 | 185 |
| Nonlinear gain | 1 | 2.5 | 3.8 | 5.1 | 6.8 | 8.9 | 12.7 | 17.9 |