1. Introduction
Semiconductorlaserdiodesarecompact,efficientandlow-cost,butusually
have poor wavelengthcontrol, linewidthand stability. The addition ofan
externalfrequency-selectivecavityallowscontroloftheoperatingwave-
lengthoverafewnmrange,withsub-MHzlinewidthandstability. The
MOGLabscateyelaser(seefigure1.1)ismachinedfromasolidaluminium
block,sothatthelaserisstable,robust,andinsensitivetoacousticdis-
turbances.The cavity is hermetically sealed for additional suppression of
environmentalfluctuationsanddrift.Thecateyelaserblockismountedon
astandardchassis(CEL)oranextendedchassis(CEX)whichcanoptionally
include a fibre output (CEF).
Figure 1.1: The MOGLabs CEL cateye laser. Mechanical version from 2023
shown (serial A323xxxxx and above).
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