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Covesion offers several components which allow complete wavelength conversion solutions to be
constructed. The PPLN Clip, in which PPLN crystals are mounted, is designed to allow easy
handling and mounting of the crystal within the oven. The PPLN Oven permits operation of the
PPLN crystal at elevated temperature, allowing temperature tuning and minimisation of
photorefractive damage. The OC2 Temperature Controller is designed to offer optimum
temperature control of the PPLN crystal within the oven. The following document describes the
recommended operational procedures for the various components.
PPLN Clip
Covesion’s PPLN crystals are supplied mounted in clips, consisting of a clip body, an ITO coated
glass spacer, and the clip springs. The design of the clip ensures that the crystal is held in place
precisely and as such can simply be mounted in a PPLN oven. Under no circumstance should the
user attempt to remove the crystal from the clip. If unmounted crystals are required, then these
can be obtained directly from Covesion Ltd.
The crystals are marked with an alignment groove on underneath, see the diagram above. For
mounted 10, 20 and 40mm crystals, the serial number is scribed on the side of the clip and the
crystal alignment mark is also on the same side. In the case of the 1mm crystals this can be
obscured by the clip, therefore please note the serial number is scribed on the input facet side of
the clip. The gratings within a crystal increase in period the closer they are to the alignment
groove, i.e. period increases from left to right with respect to the input facet.
Users must take care not to mark the optical facets of a PPLN crystal during handling. If the optical
facet does become contaminated during use, then it can be wiped with a cotton bud soaked in
Isopropanol (IPA), although care must be taken not to damage antireflection coatings that are
present.
PPLN Oven
Covesion’s PPLN oven is designed for optimum operation of PPLN crystals at elevated
temperatures, and also offers a convenient and accurate method of mounting and aligning optical
crystals within an optical train.
email: sales@covesion.com tel: +44 (0)1794 521 638
web: www.covesion.com fax: +44 (0)8709 289 714
Figure 1. Oven top removal
Figure 2. PPLN clip installation