Optomechanical assembly
View Patent ↗A dual enclosure including an inner housing inside an outer housing is provided for an optical bench supporting a plurality of optical elements. An air gap is provided between the inner and outer housings. The inner housing may act as a heat spreader for isothermal operation, and the outer housing may act as a heat insulator. The optical bench may be disposed within the inner housing on a supporting element or elements, which thermally and mechanically decouple the optical bench from the inner housing.
1. An optomechanical assembly comprising:
an optical bench;
a plurality of optical components supported by the optical bench;
an inner heat-spreader housing defining a wall and a first cavity, wherein
the inner heat-spreader housing has a heat conductivity of at least 50 W/m·K;
first support elements mechanically coupled to the inner heat-spreader housing, wherein
the first support elements contact the wall and extend vertically from the wall and into contact with a portion of the optical bench to isolate the wall from the optical bench,
the wall being a non-side wall, and
the first support elements support the optical bench in the first cavity spaced apart from the wall for decreasing a transfer of mechanical stress and heat from outside the first cavity to the optical bench;
a thermal element thermally coupled to the inner heat-spreader housing for adjusting a temperature thereof; and
an outer heat-insulator housing for defining a second cavity and supporting the inner heat-spreader housing therein so that an air gap is provided in the second cavity between the inner heat-spreader housing and the outer heat-insulator housing,
wherein the outer heat-insulator housing has a heat conductivity of 0.4 W/m·K or less, and
wherein the outer heat-insulator housing supports the inner heat-spreader housing via second support elements extending vertically from an additional wall, a distance between the second support elements being greater than a distance between the first support elements.
2. The optomechanical assembly of claim 1 , wherein the first support elements have an elastic modulus of less than 10 MPa.
3. The optomechanical assembly of claim 1 , wherein
the plurality of optical components are thermally matched to the optical bench to within 2 ppm/° C., and
the optical bench has an elastic modulus of between 70,000 MPa and 320,000 MPa.
4. The optomechanical assembly of claim 1 , further comprising:
a temperature sensor, thermally coupled to the inner heat-spreader housing, for determining the temperature thereof.
5. The optomechanical assembly of claim 1 , wherein the thermal element comprises a first thermoelectric cooler partially disposed in the second cavity.
6. The optomechanical assembly of claim 5 , wherein
the plurality of optical components extend from the optical bench in a first direction,
the thermal element further comprises a second thermoelectric cooler partially disposed in the second cavity, and
the first and second thermoelectric coolers extend from the inner heat-spreader housing and through the second cavity in opposite directions perpendicular to the first direction.
7. The optomechanical assembly of claim 6 , further comprising:
a plurality of optical and electrical ports extending through the inner heat-spreader housing and into the second cavity perpendicular to the first direction.
8. The optomechanical assembly of claim 1 , wherein the plurality of optical components comprise a diffraction grating.
9. The optomechanical assembly of claim 1 , wherein the plurality of optical components comprise a liquid crystal array.
10. The optomechanical assembly of claim 1 , wherein the plurality of optical components comprise a wavelength-selective optical switch.
11. The optomechanical assembly of claim 1 , wherein the inner heat-spreader housing comprises a hermetically sealable package comprising a plurality of optical and electrical ports extending therethrough.
12. The optomechanical assembly of claim 1 , wherein the inner heat-spreader housing comprises aluminum or copper.
13. The optomechanical assembly of claim 1 , wherein the optical bench comprises Kovar.
14. The optomechanical assembly of claim 1 , wherein the outer heat-insulator housing comprises a plastic material.
15. The optomechanical assembly of claim 1 , wherein the outer heat-insulator housing comprises an injection-molded shape including a standoff for supporting the inner heat-spreader housing therein.
16. The optomechanical assembly of claim 1 , wherein
the plurality of optical components extend from the optical bench in a first direction;
the inner heat-spreader housing has an outside perimeter wall extending parallel to the first direction,
the thermal element comprises a heater extending along the outside perimeter wall, and
the optomechanical assembly further comprises:
a temperature sensor, thermally coupled to the inner heat-spreader housing, for determining the temperature thereof.
17. A method of packaging an optical bench supporting a plurality of optical components, the method comprising:
providing an inner heat-spreader housing having a heat conductivity of at least 50 W/m·K and defining a wall and a first cavity;
supporting the optical bench, within the first cavity spaced apart from the wall, by first support elements for decreasing a mechanical stress and heat transfer to the optical bench,
wherein the first support elements contact the wall and extend vertically from the wall and into contact with a portion of the optical bench to isolate the wall from the optical bench, and
wherein the wall is a non-side wall;
thermally coupling a thermal element to the inner heat-spreader housing for adjusting a temperature thereof;
providing an outer heat-insulator housing defining a second cavity; and
supporting the inner heat-spreader housing, within the second cavity, so that an air gap is provided in the second cavity between the outer heat-insulator housing and the inner heat-spreader housing,
wherein the outer heat-insulator housing has a heat conductivity of no greater than 2 W/m·K, and
wherein the outer heat-insulator housing supports the inner heat-spreader housing via second support elements extending vertically from an additional wall, a distance between the second support elements being greater than a distance between the first support elements.
18. The method of claim 17 , wherein the first support elements have an elastic modulus of less than 10 MPa.
19. The method of claim 18 , further comprising:
hermetically sealing the first cavity.
20. The method of claim 19 , further comprising:
injection molding the outer heat-insulator housing out of a plastic material.