For the past day or so the diode chiller temperature has been fluctuating by a couple of degrees with a period
of ~90 seconds.  The fluctuations are noticeable in the temperature of the diode box heatsinks, and in the
injection locking voltage for the oscillator.  Maybe not so noticeable in the output power of the oscillator,
and not in the diode box output power.

    The diode TECs are compensating for the temperature fluctuations.  Since the TECs solely adjust the temperature
of the laser diodes, the temperature fluctuations are clearly caused by the diode chiller.