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US 7,130,320 B2Granted
External cavity laser with rotary tuning element
AssigneeMitutoyo Corporation
InventorsJoseph D. Tobiason, David W. Sesko
Life of this patent
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Abstract
An external cavity laser has a wavelength of the laser output that is tuned by a rotary tuning element mounted on the axle of a motor. The rotary tuning element includes a variable thickness interference film for wavelength selection, and a variable thickness compensation prism to adjust the cavity length appropriately for the selected wavelength, to stable wavelengths and mode-hop-free tuning ranges as the tuning element is rotated.
Claims20
A rotary tuning element, comprising:
- a variable transmission filter, having a transmission wavelength that varies as a function of rotation angle;
- a compensation prism having a thickness that varies as a function of rotation angle, the compensation prism usable to alter a cavity length of an external cavity laser to correspond to the transmission wavelength of the variable transmission filter;
- a first etalon having a transmission wavelength that varies as a function of rotation angle in a manner that corresponds to the transmission wavelength of the variable transmission filter;
- and
- a second etalon having a transmission wavelength that varies as a function of rotation angle in a manner that corresponds to the transmission wavelength of the variable transmission filter,
- wherein:
- the first and second etalon are arranged in series along a nominal optical path through the rotary tuning element;
- and
- the variable transmission filter, the compensation prism, and the first and second etalons are arranged such that the rotary tuning element is usable to provide nominally mode-hop free tuning when positioned along an optical path of an external cavity laser.
6 more elements
An external cavity laser, comprising
- a laser diode;
- a reflector;
- a rotary tuning element comprising a variable transmission filter, having a transmission wavelength that varies as a function of rotation angle, and a compensation prism having a thickness that varies as a function of rotation angle, the compensation prism usable to alter a cavity length of an external cavity laser to correspond to the transmission wavelength of the variable transmission filter;
- and
- a rotary motor usable to rotate the rotary tuning element,
- wherein:
- the rotary tuning element is operably disposed along an optical path between the laser diode and the reflector;
- and
- the rotary tuning element includes a pattern that is replicated multiple times around the rotary tuning element as a function of rotation angle and the external cavity laser is operable to provide a variable wavelength output that is mode-hop free and that repetitively varies without the use of reciprocal motion.
6 more elements
Dependencies are inferred from the claim text.