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Thermal compensator for closed-cycle helium refrigeratorThe wave length of an infrared, semiconductor laser diode having an output frequency that is dependent on the diode temperature is maintained substantially constant by maintaining the diode temperature constant. The diode is carried by a cold tip of a closed cycle helium refrigerator. The refrigerator has a tendency to cause the temperature of the cold tip to oscillate. A heater diode and a sensor diode are placed on a thermal heat sink that is the only highly conductive thermal path between the laser diode and the cold tip. The heat sink has a small volume and low thermal capacitance so that the sensing diode is at substantially the same temperature as the heater diode and substantially no thermal lag exists between them. The sensor diode is connected in a negative feedback circuit with the heater diode so that the tendency of the laser diode to thermally oscillate is virtually eliminated.
Document ID
19790008858
Acquisition Source
Legacy CDMS
Document Type
Other - Patent
Authors
Jennings, D. E. (NAS-NRC Washington, D.C., United States)
Hillman, J. J. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
September 3, 2013
Publication Date
January 16, 1979
Subject Category
Engineering (General)
Report/Patent Number
Patent Application Number: US-PATENT-APPL-SN-838337
Patent Number: US-PATENT-4,134,447
Patent Number: NASA-CASE-GSC-12168-1
Accession Number
79N17029
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Patent
US-PATENT-4,134,447|NASA-CASE-GSC-12168-1
Patent Application
US-PATENT-APPL-SN-838337

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