Wavelength division multiplexer with multiple inputs and outputs

A wavelength division multiplexer (WDM) comprising:

• a gradient-index (GRIN) lens including first and second surfaces on opposite sides or ends of the GRIN lens;
• a first plurality or array of common optical fibers, each positioned to input light into the first surface of the GRIN lens and to receive light from the first surface of the GRIN lens;
• a second plurality or array of reflected optical fibers, each positioned to input light into the first surface of the GRIN lens and to receive light from the first surface of the GRIN lens;
• a third plurality or array of transmit optical fibers, each positioned to input light into the first surface of the GRIN lens and to receive light from the first surface of the GRIN lens;
• a WDM filter including first and second surfaces on opposite sides or ends of the WDM filter, the first surface of the WDM filter coupled to the second surface of the GRIN lens;
• and
• a mirror coupled to the second surface of the WDM filter, wherein:
• light having first and second wavelengths output by each common optical fiber propagates through the GRIN lens to the WDM filter which:
• (1) reflects the light of the first wavelength back through the GRIN lens to a unique one of the reflected optical fibers but to no other optical fiber of the array of reflected optical fibers, the array of transmit optical fibers, and the array of common optical fibers, and
• (2) passes the light of the second wavelength to the mirror which reflects the light of the second wavelength back through the WDM filter and the GRIN lens to a unique one of the transmit optical fibers but to no other optical fiber of the array of transmit optical fibers, the array of reflected optical fibers, and the array of common optical fibers.

A wavelength division multiplexer (WDM) comprising:

• a WDM filter;
• a first lens array including a first substrate including plurality of spherical or aspherical lenses positioned on a first side of the WDM filter;
• a second lens array including a second substrate including a plurality of spherical or aspherical lenses positioned on a second side of the WDM filter, wherein each spherical or aspherical lens of the first and second lens arrays includes a rounded, spherical or aspherical surface facing the WDM filter;
• a first plurality or array of common optical fibers, each positioned to input light into one spherical or aspherical lens of the first lens array and to receive light from the one spherical or aspherical lens of the first lens array;
• a second plurality or array of reflected optical fibers, each positioned to input light into one spherical or aspherical lens of the first lens array and to receive light from the one spherical or aspherical lens of the first lens array;
• and
• a third plurality or array of transmit optical fibers, each positioned to input light into one spherical or aspherical lens of the second lens array and to receive light from the one spherical or aspherical lens of the second lens array, wherein:
• light having first and second wavelengths output by each common optical fiber propagates through one spherical or aspherical lens of the first lens array to the WDM filter which:
• (1) reflects the light of the first wavelength back through the one spherical or aspherical lens of the first lens array to the reflected optical fiber positioned to receive light from the one spherical or aspherical lens of the first lens array but to no other optical fiber of the array of reflected optical fibers, the array of transmit optical fibers, and the array of common optical fibers, and
• (2) passes the light of the second wavelength through one spherical or aspherical lens of the second lens array to a unique one of the transmit optical fibers but to no other optical fiber of the array of transmit optical fibers, the array of reflected optical fibers, and the array of common optical fibers.

A wavelength division multiplexer (WDM) comprising:

• a WDM filter;
• an optical fiber array including a first plurality or array of common optical fibers, a second plurality or array of reflected optical fibers, and a third plurality or array of transmit optical fibers,
• a lens array including a substrate including plurality of spherical or aspherical lenses positioned on a first side of the WDM filter, wherein each spherical or aspherical lens includes a rounded, spherical or aspherical surface facing the WDM filter, wherein:
• each spherical or aspherical lens of a first subset of the spherical or aspherical lenses has associated therewith a unique common-reflected optical fiber pair, each of which optical fiber of said unique optical fiber pair is positioned to input light into the spherical or aspherical lens of the first subset of the spherical or aspherical lenses and to receive light from the spherical or aspherical lens of the first subset of the spherical or aspherical lenses;
• and
• each spherical or aspherical lens of a second subset of the spherical or aspherical lenses has associated therewith at least one unique transmit optical fiber positioned to input light into the spherical or aspherical lens of the second subset of the spherical or aspherical lenses and to receive light from the spherical or aspherical lens of the second subset of the spherical or aspherical lenses;
• and
• a mirror positioned on a second side of the WDM filter, wherein:
• light having first and second wavelengths output by each common optical fiber propagates through one spherical or aspherical lens of the first subset of spherical or aspherical lenses to the WDM filter which:
• (1) reflects the light of the first wavelength back through the one spherical or aspherical lens of the first subset of spherical or aspherical lenses to the reflected optical fiber positioned to receive light from the one spherical or aspherical lens of the first subset of spherical or aspherical lenses but to no other optical fiber of the array of reflected optical fibers, the array of transmit optical fibers, and the array of common optical fibers, and
• (2) passes the light of the second wavelength to the mirror which reflects the light of the second wavelength back through the WDM filter to one spherical or aspherical lens of the second subset of spherical or aspherical lenses and to the unique transmit optical fiber positioned to receive light from the one spherical or aspherical lens of the second subset of the spherical or aspherical lenses but to no other optical fiber of the array of transmit optical fibers, the array of reflected optical fibers, and the array of common optical fibers.