A housing is provided for maintaining a planar lightguide circuit at a temperature within a predetermined temperature range independent of ambient temperature. The housing includes a planar heating arrangement supporting and in thermal contact with the planar lightguide circuit. Also included is a frame...http://www.google.se/patents/US6703588?utm_source=gb-gplus-sharePatent US6703588 - Compact, thermally stabilized housing for planar lightguide circuits
