Multi-channel optical coupler

1. An optical coupler for a plurality of optical fibers, comprising:

a molded coupling module comprising a first surface, a second surface, a lens array receptacle, and one or more fiber receptacles configured to receive the plurality of optical fibers;

an optical arrangement comprising:

a particular surface carrying a reflective coating, and

a further surface opposite the particular surface and carrying a plurality of optical filters, each optical filter configured to pass a single optical wavelength,

wherein the optical arrangement has a thickness, T, between the particular surface and the further surface;

a first lens array comprising a plurality of first lenses arranged with a first lens pitch, wherein the first lens array is arranged with the lens array receptacle such that each first lens is associated with a particular optical fiber and is optically aligned with the plurality of optical filters via at least the reflective coating; and

a second lens array comprising a plurality of second lenses arranged with a second lens pitch, wherein the second lens array is arranged with the second surface of the molded coupling module such that each lens of the second lens array is optically aligned with a corresponding one of the plurality of optical filters,

wherein T, the first lens pitch, and the second lens pitch are configured such that the optical coupler produces no more than −10 dB of crosstalk on any of the optical wavelengths passed by the plurality of optical filters, and

wherein the first lens array is configured such that each lens in the first lens array is non-collimating with respect to light received from a corresponding fiber.

2. The optical coupler of claim 1 , further comprising one or more optical beam reflectors arranged with the second surface of the molded coupling module, such that the first lens array is optically aligned with the plurality of optical filters via the one or more optical beam reflectors and the reflective coating.

3. The optical coupler of claim 1 , wherein the further surface of the optical arrangement is mounted to the first surface of the molded coupling module such that the first lens array is optically aligned with the plurality of optical filters via only the reflective coating.

4. The optical coupler of claim 1 , wherein the optical arrangement is configured such that the further surface carries a substantially opaque coating having a footprint that substantially surrounds the perimeter of the plurality of optical filters and substantially covers any intermediate gaps between the plurality of optical filters without substantially interfering with the direct optical paths through the plurality of optical filters.

5. The optical coupler of claim 1 , wherein the plurality of optical filters are arranged in an array comprising:

a number of rows corresponding to the plurality of fibers; and

a number of columns corresponding to a maximum number of optical wavelengths supported for any of the plurality of optical fibers.

6. The optical coupler of claim 5 , wherein all optical filters of a particular column are configured to pass the same optical wavelength.

7. The optical coupler of claim 5 , wherein a subset of the optical filters of a particular column are configured to pass a different optical wavelength than a different subset of the optical filters of the particular column.

8. The optical coupler of claim 1 , wherein each lens in the second lens array is non-collimating with respect to light received from the corresponding optical filter.

9. The optical coupler of claim 1 , wherein the first and second surfaces are substantially parallel, and the second lens array comprises a plurality of off-axis, aspherical lenses.

10. The optical coupler of claim 1 , wherein the first and second surfaces are substantially non-parallel, and the second lens array comprises a plurality of on-axis, aspherical lenses.

11. The optical coupler of claim 1 , further comprising a plurality of optical inserts, each optical insert coupled to a particular lens of the first lens array and positioned in optical alignment between the particular lens and a position, within one of the fiber receptacles, corresponding to an end of an optical fiber.

12. The optical coupler of claim 1 , wherein the one or more fiber receptacles are configured to mate with a plurality of multi-mode fibers having respective ends polished to angles, relative to the respective longitudinal axes of the fibers, of less than or equal to 85 degrees.

13. The optical coupler of claim 12 , wherein:

the one of more fiber receptacles comprise a plurality of fiber stubs;

each particular stub of the plurality of fiber stubs corresponds to a particular fiber of the plurality of multi-mode fibers; and

each particular stub has an end polished at a particular angle to mate with a polished end of the corresponding particular fiber.

14. A wavelength-division multiplexer comprising:

a substrate;

the optical coupler of claim 1 mounted to the substrate; and

a plurality of light sources mounted to the substrate and configured such that each light source is optically aligned with a corresponding lens of the second lens array.

15. A wavelength-division demultiplexer comprising:

a substrate;

the optical coupler of claim 1 mounted to the substrate; and

a plurality of photodiodes mounted to the substrate and configured such that each photodiode is optically aligned with a corresponding lens of the second lens array.

16. A wavelength-division transmitter/receiver comprising:

a substrate;

the optical coupler of claim 1 mounted to the substrate;

a plurality of photodiodes mounted to the substrate and configured such that each photodiode is optically aligned with a corresponding lens of a first portion of the second lens array; and

a plurality of light sources mounted to the substrate and configured such that each light source is optically aligned with a corresponding lens of a second portion of the second lens array.

17. A fiber-to-fiber multiplexer/demultiplexer comprising:

a substrate;

the optical coupler of claim 1 mounted to the substrate; and

a further plurality of fiber receptacles mounted to the substrate such that, within each of the further fiber receptacles, a position corresponding to the end of an optical fiber is optically aligned with a corresponding lens of the second lens array.

18. An optical coupler for a plurality of optical fibers, comprising:

a molded coupling module comprising a first surface, a second surface, a lens array receptacle, and one or more fiber receptacles configured to receive the plurality of optical fibers;

an optical arrangement comprising:

a particular surface carrying a reflective coating, and

a further surface opposite the particular surface and carrying a plurality of optical filters, each optical filter configured to pass a single optical wavelength,

wherein the optical arrangement has a thickness, T, between the particular surface and the further surface;

a first lens array comprising a plurality of first lenses arranged with a first lens pitch, wherein the first lens array is arranged with the lens array receptacle such that each first lens is associated with a particular optical fiber and is optically aligned with the plurality of optical filters via at least the reflective coating; and

a second lens array comprising a plurality of second lenses arranged with a second lens pitch, wherein the second lens array is arranged with the second surface of the molded coupling module such that each lens of the second lens array is optically aligned with a corresponding one of the plurality of optical filters,

wherein T, the first lens pitch, and the second lens pitch are configured such that the optical coupler produces no more than −10 dB of crosstalk on any of the optical wavelengths passed by the plurality of optical filters,

wherein the optical arrangement comprises an optical block having the particular surface and the further surface on opposite faces, and

wherein the further surface of the optical block is mounted to the first surface of the molded coupling module.

19. The optical coupler of claim 18 , wherein the plurality of optical filters are arranged in an array comprising:

a number of rows corresponding to the plurality of fibers; and

a number of columns corresponding to a maximum number of optical wavelengths supported for any of the plurality of optical fibers.

20. An optical coupler for a plurality of optical fibers, comprising:

a molded coupling module comprising a first surface, a second surface, a lens array receptacle, and one or more fiber receptacles configured to receive the plurality of optical fibers;

an optical arrangement comprising:

a particular surface carrying a reflective coating, and

a further surface opposite the particular surface and carrying a plurality of optical filters, each optical filter configured to pass a single optical wavelength,

wherein the optical arrangement has a thickness, T, between the particular surface and the further surface;

a first lens array comprising a plurality of first lenses arranged with a first lens pitch,

wherein the first lens array is arranged with the lens array receptacle such that each first lens is associated with a particular optical fiber and is optically aligned with the plurality of optical filters via at least the reflective coating; and

a second lens array comprising a plurality of second lenses arranged with a second lens pitch, wherein the second lens array is arranged with the second surface of the molded coupling module such that each lens of the second lens array is optically aligned with a corresponding one of the plurality of optical filters,

wherein T, the first lens pitch, and the second lens pitch are configured such that the optical coupler produces no more than −10 dB of crosstalk on any of the optical wavelengths passed by the plurality of optical filters,

wherein the molded coupling module comprises the further surface on which the plurality of optical filters are mounted, and

wherein the particular surface carrying the reflective coating is mounted to the first surface of the molded coupling module, such that a cavity exists between the reflective coating and the plurality of optical filters.