4 Chapter 1. Introduction
1.3 Temperature and current
Thelaserfrequencyisalsodependentontemperature andinjectioncur-
rent; the sensitivitiesare typically3MHz/µA and 30GHz/K[4]. Thus,
low-noisestable electronics, such asthe MOGLabs DLC externalcavity
diode lasercontroller, are essential [5] to achievesub-MHz linewidth and
stability.
An important aspectof an ECDLis temperaturecontrol ofthe cavity,since
thelaserfrequencydependsonthecavitylengthandhenceonthethermal
expansioncoefficientofthecavitymaterial[6].Thecavitycanbemachined
frommaterialswithlowthermalexpansioncoefficientbuteventhenthe
passive stabilityisinadequateforresearch applications. Activefeedback
ofthecavitytemperatureandpiezocavitylengthprovideflexibleandstable
control.TheMOGLabscateyelaserusesanegativetemperaturecoefficient
(NTC)thermistortosensethecavitytemperatureandPeltierthermoelectric
cooler (TEC) to heat and cool the cavity material.
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