Not applicable.
Not applicable.
A passive optical network (PON) is one system for providing network access over the last mile. A PON may be a point-to-multipoint (P2MP) network with passive splitters positioned in an optical distribution network (ODN) to enable a single feeding fiber from a central office to serve multiple customer premises. A PON may employ one wavelength for upstream traffic and another for downstream traffic on a single fiber. For example, the upstream traffic may be carried by a 1310 nanometer (nm) wavelength light and the downstream traffic may be carried by a 1490 nm wavelength light. As such, a PON transceiver may employ a transmitter optical sub-assembly (TOSA) package and a receiver optical sub-assembly (ROSA) package to couple an outgoing light emitted from a transmitter optically with a single fiber and also to couple an incoming light from the single fiber to a receiver.
Wavelength division multiplexers/demultiplexers are widely used in fiber optic TOSA/ROSA packages in both telecommunication and data center industries. In current markets, demand for small size and low cost modules, like Quad Small Form-Factor Pluggable 28 (QSFP28 and uQSFP28) packages, is increasing. This is especially true in the data center applications, which require miniaturization and low cost for the TOSA/ROSA packages. The typical multiplexer/demultiplexer (mux/demux) consists of multiple standalone components in the packaging, such as a fiber receptacle, a collimate lens, an optic mux/demux block, and a focal lens array. Integration of these components into a single piece monolithic component is a typical solution to reduce the size and cost. For example, the monolithic component may be made from UItem® plastic, which is widely used in optical packaging due to UItem® plastic having stable mechanical and thermal characteristics. An example of a prior art wavelength division mux/demux can be found in U.S. Pat. No. 6,201,908, which discloses a fiber optic fiber receptacle, a collimate lens, an internal reflector, as well as an aspheric lens molded in a single piece.
According to one aspect of the present disclosure, there is provided an optical wavelength division demultiplexer that includes a receptacle having a collimate lens and configured to receive an inlet light, a substrate, a reflector mounted to the substrate and configured to reflect the inlet light and separate the inlet light into multiple wavelengths, a demultiplexer block coupled to the substrate and configured to receive the inlet light from the reflector, a folding prism coupled to the substrate and configured to receive the multiple wavelengths from the demultiplexer block and refract the multiple wavelengths through the substrate, and a focal lens array coupled to the substrate substantially opposite the folding prism and configured to receive and focus the refracted multiple wavelengths.
Optionally, in any of the preceding aspects, another implementation of the aspect provides that the reflector is a fixed reflector or an adjustably-affixed reflector.
Optionally, in any of the preceding aspects, another implementation of the aspect provides that the reflector is either an external reflector or an internal reflector.
Optionally, in any of the preceding aspects, another implementation of the aspect provides that a surface of the reflector is coated with at least one of a high reflective coating or a metal layer.
Optionally, in any of the preceding aspects, another implementation of the aspect provides that the receptacle, the substrate, and the folding prism are part of a single molded piece, and that the reflector is separate from the single molded piece and bonded to the single molded piece after alignment.
Optionally, in any of the preceding aspects, another implementation of the aspect provides that the reflector is adjusted in both linear position and angular orientation before being affixed to the substrate to control an incident angle and an incident location of the inlet light reflected into the demultiplexer block.
Optionally, in any of the preceding aspects, another implementation of the aspect provides that an optical path of the inlet light is directed through the reflector and the demultiplexer block to the folding prism in a first plane, and the refracted multiple wavelengths exit the focal lens array in a direction substantially perpendicular to the first plane.
Further, according to one aspect of the present disclosure, there is provided a method that includes receiving, at a receptacle having a collimate lens, an inlet light, reflecting, by a reflector mounted to a substrate, the inlet light at an angle, receiving, by a demultiplexer block coupled to the substrate, the inlet light from the reflector, separating, by the demultiplexer block, the inlet light into multiple wavelengths, receiving, by a folding prism coupled to the substrate, the multiple wavelengths from the demultiplexer block, refracting, by the folding prism, the multiple wavelengths through the substrate, and focusing, by a focal lens array coupled to the substrate substantially opposite the folding prism, the refracted multiple wavelengths.
Optionally, in any of the preceding aspects, another implementation of the aspect provides that the reflector is a fixed reflector or an adjustably-affixed reflector.
Optionally, in any of the preceding aspects, another implementation of the aspect provides that the reflector is either an external reflector or an internal reflector.
Optionally, in any of the preceding aspects, another implementation of the aspect provides that a surface of the reflector is coated with at least one of a high reflective coating or a metal layer.
Optionally, in any of the preceding aspects, another implementation of the aspect provides that the receptacle, the substrate, and the folding prism are part of a single molded piece, and that the reflector is separate from the single molded piece and bonded to the single molded piece after alignment.
Optionally, in any of the preceding aspects, another implementation of the aspect provides that the reflector is adjusted in both linear position and angular orientation before being affixed to the substrate to control an incident angle and an incident location of the inlet light reflected into the demultiplexer block.
Optionally, in any of the preceding aspects, another implementation of the aspect provides that an optical path of the inlet light is directed through the reflector and the demultiplexer block to the folding prism in a first plane, and the refracted multiple wavelengths exit the focal lens array in a direction substantially perpendicular to the first plane.
Moreover, according to one aspect of the present disclosure, there is provided an optical wavelength division multiplexer that includes a substrate having a first side and a second side, a focal lens array coupled to the first side of the substrate and configured to receive and focus the multiple wavelengths intended for transmission, a folding prism coupled to the second side of the substrate substantially opposite the focal lens array and configured to receive the multiple wavelengths from the focal lens array and refract the multiple wavelengths through the substrate, a multiplexer block coupled to the second side of the substrate and configured to receive the multiple wavelengths from the folding prism, wherein the multiplexer block combines the multiple wavelengths into a combined beam, a reflector mounted to the second side of the substrate and configured to reflect the combined beam at an angle, and a receptacle having a collimate lens and configured to receive the combined beam from the reflector and transmit an outlet light.
Optionally, in any of the preceding aspects, another implementation of the aspect provides that the reflector is a fixed reflector or an adjustably-affixed reflector.
Optionally, in any of the preceding aspects, another implementation of the aspect provides that the reflector is either an external reflector or an internal reflector.
Optionally, in any of the preceding aspects, another implementation of the aspect provides that the receptacle, the substrate, and the folding prism are part of a single molded piece, and that the reflector is separate from the single molded piece and bonded to the single molded piece after alignment.
Optionally, in any of the preceding aspects, another implementation of the aspect provides that the reflector is adjusted in both linear position and angular orientation before being affixed to the substrate to control an incident angle and an incident location of the combined beam reflected into the receptacle.
Optionally, in any of the preceding aspects, another implementation of the aspect provides that the combined beam is directed from the folding prism through the multiplexer block and the reflector in an optical path in a first plane, and the multiple wavelengths intended for transmission enter the focal lens array in a direction substantially perpendicular to the first plane.
Any of the above embodiments may be combined with any of the other above embodiments to create a new embodiment. These and other features will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings and claims.
For a more complete understanding of this disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts.
It should be understood at the outset that although an illustrative implementation of one or more embodiments are provided below, the disclosed systems and/or methods may be implemented using any number of techniques, whether currently known or in existence. The disclosure should in no way be limited to the illustrative implementations, drawings, and techniques illustrated below, including the exemplary designs and implementations illustrated and described herein, but may be modified within the scope of the appended claims along with their full scope of equivalents.
The previously discussed monolithic optical package may have drawbacks in optimizing the optical performance and component layout due to manufacturing limitations. Since all the components are molded in a single piece, the mux/demux does not allow for any optical adjustment during assembly. Therefore, an incident angle into the mux/demux as well as the accuracy of the pitch and locations of optical focal points are pre-determined by the accuracy of the components as well as the accuracy of the bonding processes. This may result in both unfavorable optical performance and cost of assembly. As such, the present disclosure identifies a need for improved miniaturization, reduced cost, and optical performance in optical packages.
Disclosed herein is a mux/demux apparatus having a single molded component comprising a receptacle, a demultiplexer block, a folding prism, or a combination thereof, which can result in more accurate and cost effective multiplexer and demultiplexer apparatuses. The mux/demux apparatus also includes a reflector that can be either fixed or adjustably-affixed during assembly. A fixed reflector is part of a single piece molded apparatus. An adjustably-affixed reflector is bonded to the single molded component after the reflector is aligned and adjusted for optical performance during the assembly process. The adjustably-affixed reflector can be adjusted to control both the incident angle and the incident location with the demultiplexer block. Further, an optical path of the light beam, which defines a first plane, travels through the reflector and the demultiplexer to the folding prism, and exits the folding prism in a direction substantially perpendicular to the first plane, and light focal points are located off a centerline of the apparatus.
The various embodiments disclosed herein will be described as a demultiplexer, although the same embodiments can also be implemented as a multiplexer by reversing the optical path. The disclosed mux/demux can be used in high speed TOSA/ROSA applications. Further, the mux/demux may be advantageous due to the high integration of packaging of single molded components, and due to the flexible optical adjustment of the reflector.
In accordance with various embodiments,
The receptacle 110 can support communication via an optical interface. Further, the inlet light 114 from a fiber 112 embedded in the receptacle 110, either single mode or multi-mode, becomes a collimated beam 116 through the collimate lens 111.
In various embodiments, the reflector 130 is mounted to the substrate 120 and configured to reflect a collimated beam 116, for example to reflect the collimated beam 116 at a substantially right angle. For example, the collimated beam 116 is reflected at 90° (degrees), within 85° to 95°, or within 80° to 100° from the direction of the collimated beam 116 exiting the reflector 130 relative to the direction entering the reflector 130. Reflector 130 reflects the collimated beam 116, as reflected beam 117, according to a total internal reflection, toward the demultiplexer block 140. In various embodiments, the reflector 130 is a fixed reflector and molded as part of the apparatus, as shown in
In various embodiments, the demultiplexer block 140 is coupled to the substrate 120 and configured to receive the reflected beam 117 from the reflector 130. The demultiplexer block 140 comprises an optical block 141 having a reflective surface 142 and a plurality of filters 143 or filter regions. The reflective surface 142 is coated with a reflective layer to reflect the reflected beam 117. The reflective layer can be gold, aluminum, or similar metal, for example. The plurality of filters 143 is configured to filter the multiple wavelengths (λ1, λ2, λ3, and λ4) within the reflected beam 117. The reflected beam 117 is reflected in a zigzag pattern in the demultiplexer block 140 between the plurality of filters 143 and the reflective surface 142. As the reflected beam 117 enters each of the plurality of filters 143, one of n different multiple wavelengths (λ1, λ2, λ3, and λ4) of light is transmitted through each of the plurality of filters 143 and the separated multiple wavelengths (λ1, λ2, λ3, and λ4) move along the optical pathways toward the folding prism 150.
For example and with reference to
In various embodiments, the demultiplexer block 140 can be formed from glass or molded plastic. However, it should be understood that other optical materials can be employed in forming the demultiplexer block 140. Further, the demultiplexer block 140 can also be bonded to the optical wavelength division demultiplexer 100 or can be formed as a portion of the optical wavelength division demultiplexer 100.
The folding prism 150 is coupled to the substrate 120 and configured to receive the filtered multiple wavelengths (λ1, λ2, λ3, and λ4) from the demultiplexer block 140 and refract the multiple wavelengths (λ1, λ2, λ3, and λ4). The multiple wavelengths (λ1, λ2, λ3, and λ4) traveling inside the folding prism 150 are refracted into a vertical or near vertical direction down towards the substrate 120, such as shown in
The focal lens array 160 comprises focal lenses 160A-D coupled to the substrate 120 opposite the folding prism 150 and configured to receive and focus the refracted multiple wavelengths (λ1, λ2, λ3, and λ4). Although shown with four focal lenses 160A-D, the focal lens array 160 can be configured for any number of wavelengths. The multiple wavelengths (λ1, λ2, λ3, and λ4) of light refracted through the folding prism 150 are focused when passing through each of the focal lenses 160A-D and reach a corresponding photodiode (not shown). The focal lens array 160 can be injection molded to the substrate 120. The lenses of each of the focal lenses 106A-D of the focal lens array 160 can be a ball lens or aspheric lens, and the pitch of the focal lens array 160 is about the same as the pitch of a demultiplexer block, such as demultiplexer block 140. Additionally, the surface of the focal lenses 160A-D can be coated with an anti-reflective layer to reduce back reflection. The anti-reflective layer can comprise multiple layers of materials with different refractive indices.
In various embodiments, the reflector 130 can be an internal reflector.
Similarly, in various embodiments, the reflector 130 can be an external reflector.
The internal reflector 230 shown in
In various embodiments and with reference to
As illustrated in
In accordance with various embodiments, the demultiplexer package, such as optical wavelength division multiplexer 100, is designed such that an optical path through the demultiplexer block 140 is substantially parallel to the substrate 120. In addition, the light focal points of the focal lens array 160 are positioned off a centerline of the demultiplexer package in some embodiments. For example,
While several embodiments have been provided in the present disclosure, it may be understood that the disclosed systems and methods might be embodied in many other specific forms without departing from the spirit or scope of the present disclosure. The present examples are to be considered as illustrative and not restrictive, and the intention is not to be limited to the details given herein. For example, the various elements or components may be combined or integrated in another system or certain features may be omitted, or not implemented.
In addition, techniques, systems, subsystems, and methods described and illustrated in the various embodiments as discrete or separate may be combined or integrated with other systems, modules, techniques, or methods without departing from the scope of the present disclosure. Other items shown or discussed as coupled or directly coupled or communicating with each other may be indirectly coupled or communicating through some interface, device, or intermediate component whether optically, mechanically, or otherwise. Other examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and may be made without departing from the spirit and scope disclosed herein.
Although the present disclosure has been described with reference to specific features and embodiments thereof, it is evident that various modifications and combinations can be made thereto without departing from scope of the disclosure. The specification and drawings are, accordingly, to be regarded simply as an illustration of the disclosure as defined by the appended claims, and are contemplated to cover any and all modifications, variations, combinations or equivalents that fall within the scope of the present disclosure.
This application is a non-provisional application of U.S. Provisional Application No. 62/361,865, filed on Jul. 13, 2016, entitled “Wavelength Division Multiplexer/Demultiplexer with Flexibility of Optical Adjustment,” which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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62361865 | Jul 2016 | US |