Optical transceiver including optical fiber coupling assembly to increase usable channel wavelengths

An optical transceiver comprising:

• a dual core optical fiber pigtail for coupling at least first and second optical fibers to an optical sub-assembly, wherein the dual core optical fiber pigtail includes first and second optical fiber cores spaced with a predefined pitch, wherein the first optical fiber and the first optical fiber core are configured to carry light within a C-band wavelength range and an L-band wavelength range, and wherein the second optical fiber and the second optical fiber core are configured to carry light within the L-band wavelength range;
• a gradient index (GRIN) lens optically coupled to the optical fiber cores, wherein the GRIN lens is configured to bend light passing through the GRIN lens;
• and
• a wavelength division multiplexing (WDM) filter optically coupled to the GRIN lens, wherein the WDM filter is configured to pass light in the C-band wavelength range and to reflect light in the L-band wavelength range, wherein the WDM filter is optically coupled to the GRIN lens such that the light in the L-band wavelength range passing from the first optical fiber core through the GRIN lens is incident on the WDM filter at an incident angle allowing the light in the L-band wavelength to reflect back to the second optical fiber core;
• a transmitter sub-assembly including a laser for emitting laser light in the C-band wavelength range, wherein the laser is positioned such that the laser light is directed at the incident angle to the WDM filter allowing the laser light in the C-band wavelength range to pass through the WDM filter, through the GRIN lens and into the first optical fiber core, and wherein the incident angle of the laser light on the WDM filter prevents back reflection of the laser light outside of the C-band wavelength range;
• and
• a receiver sub-assembly including a photodetector for detecting light in the L-band wavelength range, wherein the photodetector is coupled to the second optical fiber such that the laser light in the L-band wavelength range reflecting off of the WDM filter passes through the GRIN lens and into the second optical fiber core and the second optical fiber and is received by the photodetector.

A wavelength division multiplexed (WDM) passive optical network (PON) comprising:

• a plurality of terminals associated with different respective channel wavelengths and configured to transmit and receive optical signals on the different respective channel wavelengths, at least one of the plurality of terminals including an optical transceiver comprising:
• a dual core optical fiber pigtail for coupling at least first and second optical fibers to an optical sub-assembly, wherein the dual core optical fiber pigtail includes first and second optical fiber cores spaced with a predefined pitch, wherein the first optical fiber and the first optical fiber core are configured to carry light within a C-band wavelength range and an L-band wavelength range, and wherein the second optical fiber and the second optical fiber core are configured to carry light within the L-band wavelength range;
• a gradient index (GRIN) lens optically coupled to the optical fiber cores, wherein the GRIN lens is configured to bend light passing through the GRIN lens;
• and
• a wavelength division multiplexing (WDM) filter optically coupled to the GRIN lens, wherein the WDM filter is configured to pass light in the C-band wavelength range and to reflect light in the L-band wavelength range, wherein the WDM filter is optically coupled to the GRIN lens such that the light in the L-band wavelength range passing from the first optical fiber core through the GRIN lens is incident on the WDM filter at an incident angle allowing the light in the L-band wavelength to reflect back to the second optical fiber core;
• a transmitter sub-assembly including a laser for emitting laser light in the C-band wavelength range, wherein the laser is positioned such that the laser light is directed at the incident angle to the WDM filter allowing the laser light in the C-band wavelength range to pass through the WDM filter, through the GRIN lens and into the first optical fiber core, and wherein the incident angle of the laser light on the WDM filter prevents back reflection of the laser light outside of the C-band wavelength range;
• and
• a receiver sub-assembly including a photodetector for detecting light in the L-band wavelength range, wherein the photodetector is coupled to the second optical fiber such that the laser light in the L-band wavelength range reflecting off of the WDM filter passes through the GRIN lens and into the second optical fiber core and the second optical fiber and is received by the photodetector.