Optical switching device
View Patent ↗An optical switching device including an optical switching engine may be packaged by omitting an optical bench and disposing optical elements directly on a base of a housing of the optical switching device. The optical switching engine may be disposed on a ceramic portion of the base, and thermally matched to the ceramic base. The base may be reinforced by the housing walls and optional internal rigidity ribs. The optical elements may be thermally matched to the base, and the lid may be strain relieved by thinning lid edges. The housing may be mounted to an external chassis using soft grummets.
1. An optical switching device comprising:
at least one input port for inputting an optical signal comprising a plurality of wavelength channels;
at least one output port for outputting at least one of the wavelength channels;
optics for dispersing and redirecting the wavelength channels between the input and output ports;
a switching engine optically coupled with the optics for redirecting at least one of the wavelength channels towards a selected output port; and
a housing comprising:
a base comprising a first portion comprised of ceramic CTE matched to the switching engine to within 4 ppm/° C., wherein the switching engine is mounted directly to the ceramic first portion; and
a cover, the cover and the base enclosing and sealing the optics and the switching engine, wherein the cover is mounted directly to the base for stiffening the base;
wherein the optics are CTE matched to the base to within 4 ppm/° C. and mounted directly to the base.
2. The optical switching device of claim 1 , wherein the base further comprises a second portion extending from the ceramic first portion and comprised of metal CTE matched to the ceramic within 4 ppm/° C. for supporting at least some of the optics.
3. The optical switching device of claim 1 , wherein the ceramic first portion comprises an HTCC assembly.
4. The optical switching device of claim 1 , wherein the ceramic first portion includes an extension extending beyond the cover, and wherein the extension comprises electrical leads electrically connected to the switching engine and extending beyond the cover.
5. The optical switching device of claim 1 , wherein the housing is mounted to an external chassis via mounts having modulus of elasticity of no greater than 20 MPa.
6. The optical switching device of claim 1 , wherein the cover comprises a frame for mounting directly to the base and a lid having a perimeter and mounted to the frame along the perimeter.
7. The optical switching device of claim 6 , wherein the frame comprises an inner section disposed between the optics and the switching engine and mounted directly to the base, for further stiffening the base, and an outer section surrounding the inner section, the optics, and the switching engine.
8. The optical switching device of claim 7 , wherein the base further comprises a second portion extending from the ceramic first portion and comprised of metal CTE matched to the ceramic within 4 ppm/° C. for supporting at least some of the optics, wherein the second portion comprises the inner section of the frame.
9. The optical switching device of claim 1 , wherein the cover comprises an opening for equating ambient air pressure and inside air pressure.
10. The optical switching device of claim 9 , wherein the optical switching device further comprises a pressure sensor for sensing the ambient air pressure for lessening a wavelength drift of the optical switching device.
11. The optical switching device of claim 1 , wherein the switching engine comprises an LCoS array.
12. The optical switching device of claim 1 , wherein the base further comprises a second portion extending from the ceramic first portion, and wherein the housing further comprises a compensating plate mounted directly to the second portion and having a CTE different from a CTE of the second portion by at least 1 ppm/° C., for introducing thermally dependent deformations for lessening a wavelength drift of the optical switching device with temperature.
13. The optical switching device of claim 6 , wherein the cover further comprises a seal ring mounted directly to the frame and the lid outside of the frame along the perimeter of the lid.
14. The optical switching device of claim 13 , wherein the frame is soldered to the base using a solder having a melting temperature of less than 300° C., and wherein the seal ring is soldered to the frame and the lid using a solder having a melting temperature of less than 140° C.
15. The optical switching device of claim 6 , wherein the housing comprises a hermetic housing, and wherein the lid comprises a thinner portion around the perimeter thereof, for lessening a deformation of the base caused by a pressure differential between inside and outside the housing.
16. The optical switching device of claim 15 , wherein a thickness of the thinner portion is no greater than 0.5 mm, and wherein a geometrical area of the thinner portion is no greater than 25% of a total geometrical area of the lid.
17. The optical switching device of claim 1 , wherein the base is comprised entirely of a ceramic material.
18. The optical switching device of claim 1 , further comprising a heater thermally coupled to the housing, for maintaining the housing at a substantially constant temperature.
19. The optical switching device of claim 18 , wherein the cover comprises a heat spreader having a thermal conductivity of at least 120 W/m·K.
20. The optical switching device of claim 1 , wherein the optics comprise a diffraction grating, and wherein the switching engine comprises an LCoS array, a MEMS array, or a diffractive beamsplitter.