Modular optical device package compatible with multiple fiber connectors

Embodiments of the present invention are directed to modular optical devices compatible with multiple fiber connectors. A lens block is configured such that one or more lens pins can mechanically couple to the lens block and such that the lens block can mechanically couple to a fabricated package that includes light transmitting and/or detecting components. At least one lens pin has a fiber stop configured to accept a fiber end prepared for use with a first type of fiber connector. A fiber stop disk alters the configuration of the lens pin such that the lens pin can compatibly accept a fiber end prepared for use with a second different type of fiber connector not withstanding that the fiber stop is configured to accept a fiber end prepared for use with the first type of fiber connector.

BACKGROUND OF THE INVENTION

1. The Field of the Invention

The present invention is generally related to optical devices used in fiber optic communications systems. More particularly, the present invention provides for compact low cost modular optical devices compatible with multiple fiber connectors.

2. The Relevant Technology

Fiber optic technology is increasingly employed as a method by which information can be reliably transmitted via a communications network. Networks employing fiber optic technology are known as optical communications networks, and are marked by high bandwidth and reliable, high-speed data transmission.

Optical communications networks employ optical transceivers in transmitting information via the network from a transmission node to a reception node. Generally, such optical transceivers implement both data signal transmission and reception capabilities. For example, a transmitter portion of a transceiver is configured to convert an incoming electrical data signal into an optical data signal and a receiver portion of the transceiver is configured to convert an incoming optical data signal into an electrical data signal.

More particularly, an optical transceiver at the transmission node receives an electrical data signal from a network device, such as a computer, and converts the electrical data signal to a modulated optical data signal using an optical transmitter such as a laser. The optical data signal can then be transmitted in a fiber optic cable via the optical communications network to a reception node of the network. At the reception node, the optical data signal is received at another optical transceiver that uses a photodetector, such as a photodiode, to convert the received optical data signal back into an electrical data signal. The electrical data signal is then forwarded to a host device, such as a computer, for processing.

Generally, multiple components are designed to accomplish different aspects of these functions. For example, an optical transceiver can include one or more optical subassemblies (“OSA”) such as a transmit optical subassembly (“TOSA”), and a receive optical subassembly (“ROSA”). Typically, each OSA is created as a separate physical entity, such as a hermetically sealed cylinder that includes one or more optical sending or receiving components, as well as electrical circuitry for handling and converting between optical and electrical signals. Within the optical transceiver, each OSA generally includes electrical connections to various additional components such as a transceiver substrate, sometimes embodied in the form of a printed circuit board (“PCB”). OSAs in a conventional transceiver are generally oriented such that a longitudinal axis defined by the OSA is substantially parallel to the transceiver substrate. The transceiver substrate, in turn, is mounted to the board of a host bus adapter (“HBA”) or other component.

The transceiver substrate can include multiple other active circuitry components particularly designed to drive or handle electrical signals sent to or returning from one or more of the OSAs. Accordingly, such a transceiver substrate will usually include a number of electrical transmission lines with the one or more OSAs. Such connections may include “send” and “receive” data transmission lines for each OSA, one or more power transmission lines for each OSA, and one or more diagnostic data transmission lines for each OSA. These transmission lines are connected between the transceiver substrate and the OSA using different types of electrical connectors, examples of which include an electrical flex circuit, a direct mounting connection between conductive metallic pins extending from the OSA and solder points on the PCB, and a plug connection that extends from the PCB and mounts into electrical extensions from an OSA.

As part of ongoing efforts to uniformly reduce the size of optical transceivers and other components, manufacturing standards such as the small form factor (“SFF”), small form factor pluggable (“SFP”), and 10 gigabit small form factor pluggable (“XFP”) standards have been developed. Nonetheless, the size of most optical transceivers, even those that comply with such manufacturing standards, best suits them for external connections to a computer system, such as a desktop computer, a laptop computer, or a handheld digital device.

For example, an SFF or SFP optical transceiver can be used to provide an interface between an optical cable and a standard network cable, such as an Ethernet cable for example, that plugs into a computer system. Alternatively, a number of optical transceivers can be mounted in a network panel and configured to include an external connection to a computer system. However, the number of components within a conventional transceiver, as well as the orientation and the size of SFF or SFP optical transceivers, makes it difficult, if not impossible, to integrate conventional optical transceivers into smaller spaces, such as within a pluggable card for use in a laptop computer or hand held device. For example, despite their relatively compact nature, conventional SFF, SFP, and XFP optical transceiver bodies are still too wide and/or tall to fit within a typical PCMCIA laptop envelope.

A related problem concerns the connections of the optical transceiver. In particular, use of the optical transceiver as an external, rather than internal, component necessitates the use of additional connectors and connections, which increase both the overall cost associated with the system as well as the complexity of the system. As well, optical transceivers employed in an external, rather than integrated, configuration are more prone to rough handling and damage than an integrated component.

Furthermore, even if the conventional optical transceiver could fit within such an envelope, the length of the conventional SFF, SFP, or XFP optical transceiver is such that the transceiver substrate takes up an inordinate amount of board space on a corresponding host bus adapter (“HBA”) or other component to which the optical transceiver is attached. This problem is of particular concern in light of the concurrent demands for increases in functionality and decreases in component size. These, and other, considerations make conventional optical transceivers less than ideal for integration within many computer systems.

Additionally, optical transceivers are often designed for compatibility with a single type of fiber. A fiber optical cable typically interfaces with an optical transceiver through a lens pin that receives the fiber optical cable. Due to lens pin configurations, it is often not appropriate to use different types of fibers with different transceivers. For example, MU fibers frequently include a sharp chamfer at the fiber tip and typically cannot be used with LC configured lens pins. Accordingly, what would be advantageous are reduced cost optical transceivers that can fit within relatively small envelopes such that the optical transceivers are compatible with different types of fibers.

BRIEF SUMMARY OF THE INVENTION

The foregoing problems with the prior state of the art are overcome by the principles of the present invention, which are directed to modular optical devices compatible with multiple fiber connectors. A lens block is configured such that one or more lens pins can mechanically couple to the lens block and such that the lens block can mechanically couple to a fabricated package. A fabricated package, including a light source and/or light detector and including a connection portion for electrically coupling the fabricated package to a substrate, is mechanically coupled to the lens block. A lens pin, for transferring an optical signal between the at least one of the light source and light detector and a corresponding external component, is mechanically coupled to the lens block. The lens pin has a fiber stop configured to accept a fiber end prepared for use with a first type of fiber connector (e.g., an LC connector). A fiber stop disk is in mechanical contact with the lens pin and covers the fiber stop. The fiber stop disk alters the configuration of the lens pin such that the lens pin can compatibly accept a fiber end prepared for use with a second different type of fiber connector (e.g., an MU connector) not withstanding that the fiber stop is configured to accept a fiber end prepared for use with the first type of fiber connector (e.g., the LC connector).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The principles of the present invention relate to modular optical devices compatible with multiple fiber connectors. A lens block is configured such that one or more lens pins can mechanically couple to the lens block and such that the lens block can mechanically couple to a fabricated package. A fabricated package, including a light source and/or light detector and including a connection portion for electrically coupling the fabricated package to a substrate, is mechanically coupled to the lens block. A lens pin, for transferring an optical signal between the at least one of the light source and light detector and a corresponding external component, is mechanically coupled to the lens block. The lens pin has a fiber stop configured to accept a fiber end prepared for use with a first type of fiber connector (e.g., an LC connector). A fiber stop disk is in mechanical contact with the lens pin and covers the fiber stop. The fiber stop disk alters the configuration of the lens pin such that the lens pin can compatibly accept a fiber end prepared for use with a second different type of fiber connector (e.g., an MU connector) not withstanding that the fiber stop is configured to accept a fiber end prepared for use with the first type of fiber connector (e.g., the LC connector). The modular optical device can be coupled to a substrate configured to be received within a standard slot of a host device or system, such as a PCI or PCMCIA slot.

In general, embodiments of the present invention describe modular optical devices (e.g., TOSAs and ROSAs) that can be integrated within the relatively small physical envelopes defined by compact components, such as a Host Bus Adapter (“HBA”). Embodiments of the present invention can interoperate with a desktop computer, a laptop computer, or other similar computer system, while maintaining compliance with applicable operational and performance standards.

As used herein, “OSA” refers to any one of a transmit optical subassembly (“TOSA”) or a receive optical subassembly (“ROSA”). Further, a “substrate” refers to a printed circuit board (“PCB”) having electrically conductive elements such as circuit traces for transmitting power and/or communication signals between components in a modular optical device and another system or device, such as a computer system. A transceiver PCB can include circuits, devices and systems for facilitating the operation and control of the modular optical device. Such circuits, devices and systems include, but are not limited to, a laser driver, a post amplifier, and transimpedance amplifier.

Embodiments of the present invention include a lens block that is configured such that one or more lens pins can mechanically couple to the lens block and such that the lens block can mechanically couple to a fabricated package. Lens pins can include fiber stops and can receive fiber stop disks such that the lens pins can compatibly receive a plurality of different types of fiber connectors. Accordingly, a modular optical device can include a lens block, a fabricated package, one or more lens pins, and one or more fiber stop disks.

The fabricated package can include a light source, such as, for example, a laser (e.g., a vertical cavity surface emitting laser (“VCSEL”)) and/or light detector (e.g., photodiode) as well as corresponding openings for transmitting and receiving optical signals. The fabricated package can also include a lead frame (e.g., in thru hole pin or formed lead configuration) for connecting (e.g., utilizing corresponding thru holes or surface mounting) the fabricated package to a Printed Circuit Board Assembly (“PCBA”), such as, for example, a Host Bus Adapter (“HBA”). Alternately, the fabricated package can include a flex circuit for connecting to a PCBA. Thus, active and/or passive circuitry components for driving the light source (e.g., a laser driver), converting a received light signal (e.g., transimpedance amplifier), or for implementing other optical signal processing can be designed into the PCBA.

Configurations of the lens block can include receptacles for accepting one or more lens pins. For example, a transmission lens pin, a reception lens pin, or a combination of transmission lens pins and/or reception lens pins can be mechanically coupled to the lens block. Lens pins mechanically coupled to the lens block can provide appropriate receptacles for receiving external optical connections. Lens pins can include lenses that focus optical signals. Lens pins can include a fiber stop and can receive a fiber stop disk that facilitates the lens pins compatibly receiving a plurality of different types of fiber connectors. Fiber stop disks can be made of metal, plastic, or other appropriate materials.

Accordingly, a lens pin can direct a generated optical signal from the lens block to an external component (e.g., one of a plurality of different optical cables) or can direct a received optical signal from an external component to the lens block. For example, an optical signal generated at a laser in the fabricated package can be transferred through a corresponding lens in the lens block, transferred through a corresponding lens pin, to a corresponding optical cable. Likewise, an optical signal received from an optical cable can be transferred through a corresponding lens pin, transferred through a corresponding lens in the lens block, into a corresponding photodiode in the fabricated package.

Referring now toFIG. 1,FIG. 1illustrates a partial cut-away view of components of an example modular optical device150relative to fiber stop disks118and116. Generally, components similar to those inFIG. 1can be used in modular optical devices of various form factors, including, but not limited to, an SFF, SFP, and XFP optical transceiver. The foregoing is exemplary however, and modular optical devices can be implemented in various other forms as well. Further, embodiments of the invention are suitable for use in connection with a variety of data rates such as about 1 Gbps, about 2 Gbps, about 4 Gbps, and about 10 Gbps, or higher.

FIG. 1depicts lens pins106and108, lens block103, and fabricated package101, which have been mechanically coupled to one another to form modular optical device150. Generally, fabricated packages, lens blocks, and lens pins can be fabricated (e.g., molded, machined, cast, etc.) from plastic, metal, or any other suitable material. Fabricated package101can include a transmission opening (e.g., opening141inFIG. 2) for transmitting generated optical signals. For example, VCSEL151(Vertical Cavity Surface Emitting Laser) can transmit optical signals out of transmission opening141. Fabricated package101can also include a detector opening (e.g., opening142inFIG. 2) for detecting received optical signals. For example, photodiode152can detect optical signals received at detector opening142.

Fabricated package101also includes a formed lead frame107for connecting fabricated package101(both electrically and mechanically) to a Printed Circuit Board Assembly (“PCBA”), such as, for example, a Host Bus Adapter (“HBA”). For example, formed lead frame107can be used to surface mount fabricated package101to a PCBA. Other types of external connectors can also be used.

Lens pins106and108can be slip fit into corresponding receptacles of lens block103to facilitate transferring optical signals between fabricated package101and corresponding external components (e.g., single-mode or multi-mode fiber). Lens block103can be fit onto (e.g., placed flush against) fabricated package101. Lens block103and fabricated package101can be held together using a variety of attachment means, such as, for example, epoxy, metal clips, or laser welding. Laser welding can be particularly advantageous when lens block103and fabricated package101are made of similar plastic compounds. Lens pins (e.g., lens pins108and106) can be held to lens block103using similar means.

Lens pins106and108include fiber stops126and128respectively. Fiber stops126and128are configured to compatibly accept less chamfered fiber ends (e.g., fiber ends prepared for use with LC connectors or “LC fiber ends”). That is, fiber stops126and128prevent LC fiber ends from significantly protruding into either of cylindrical cavities146and148respectively.

Fiber stop disks can be used to alter the configuration of lens pins such that more chamfered fiber ends (e.g., fiber ends prepared for use with MU connectors or “MU fiber ends”) can be compatibly accepted into the lens pins not withstanding that corresponding fiber stops are configured to compatibly accept less chamfered fiber ends (e.g., LC fiber ends). For example, fiber stop disk118can be inserted into cylindrical cavity138and held in mechanical contact with the inside of lens pin108at fiber stop128. Similarly, fiber stop disk116can be inserted into cylindrical cavity136and held in mechanical contact with the inside of lens pin106at fiber stop126.

FIG. 2illustrates a cut-away perspective view of components of example modular optical device150including fiber stop disks118and116. The configuration inFIG. 2can facilitate lens pins106and108compatibly accepting more chamfered fiber ends (e.g., MU fiber ends) not withstanding that fiber stops126and128are configured to compatibly accept less chamfered fiber ends (e.g., LC fiber ends). That is, fiber stop disks116and118prevent the more chamfered fiber ends from protruding significantly into cylindrical cavities146and148respectively. To receive MU fiber ends fiber stop disks can be pressed into place at lens pins106and/or108. Fiber stop disks can be made by a simple, inexpensive stamping process. Fiber stop disks116and118advantageously promote appropriate alignment of MU fiber ends along the Z-axis mitigating any potential drop in performance.

Thus, light signals emitted at opening141can be transferred through lens block103and lens pin108to an MU fiber end. Likewise, light signals received from an MU fiber end can be transferred through lens pin106and lens block103and received at opening142.

FIG. 3Aillustrates an enlarged cut-away view of lens pin108configured to receive an LC fiber end181. As depicted, the diameter of LC fiber end181is greater than the diameter of cylindrical cavity148. Thus, LC fiber end181stops at fiber stop128and does not protrude significantly (or at all) into cylindrical cavity148.

FIG. 3Billustrates an enlarged cut-away view of the lens pin108configured to receive an MU fiber end183. As depicted, the diameter of the tip of MU fiber end183is smaller than the diameter of cylindrical cavity148. However, MU fiber end183stops at fiber stop disk118and does not protrude significantly (or at all) into cylindrical cavity148. Thus, fiber stop disks can be used to alter lens pins to compatibly accept MU fiber ends notwithstanding that fiber stops contained in the lens pins are configured to accept LC fiber ends.

Modular optical device150can be positioned and mounted (e.g., by connecting lead frame107) on a substrate, such as, for example, a host bus adapter. Lead frame107can facilitate electrical communication between circuitry (not shown) on the substrate (or other components to which modular optical device150is mounted) and fabricated package101. Accordingly, lead frame107enables data transmission and/or reception, as well as the transmission and reception of control and monitoring signals, between fabricated package101and a substrate. Electrical communication can include communication between a light source included in fabricated package101, such as, for example, VCSEL151and a corresponding laser driver circuit on the substrate. Likewise, electrical communication can include communication between a light detector included in fabricated package101, such as, for example, photodiode152, and a corresponding transimpedance amplifier circuit on the substrate. Lead frame107can be connected to a substrate in a variety of ways, including, but not limited to, surface mount connectors, thru hole connectors, and compression-type connectors.

Components (now shown), such as, for example, light emitting diodes, a laser driver, a post amplifier, a transimpedance amplifier, a current bias driver, volatile and/or non-volatile memory, and a thermo-electric cooler (“TEC”) can be implemented on either side of a substrate as appropriate. Implemented components can interface electrically with modular optical device150through lead frame107. Likewise, when the substrate is coupled to a computer system or other device, such implemented components can interface electrically with the computer system or other device. Mounting components, circuits and devices on both sides of a substrate can facilitate a compact structure without any meaningful loss in functionality. Moreover, as previously described, this aids space conservation on an HBA or other device to which the modular optical device150is mounted.

Further, including circuitry for interoperating with light sources and light detectors on the substrate (or other appropriate medium) reduces the circuitry that is to be included in fabricated package101. Accordingly, the number and size of components included in fabricated package101is reduced resulting in a cheaper, more compact optical device. Additionally, the reduced size allows for production of relatively shorter transceivers that can be readily integrated within various devices

Modular optical device150can be arranged such that the distance between lens pin108and lens pin106is large enough that a first optical connector can be connected to lens pin108, while a second optical connector is simultaneously connected to lens pin106and vice versa. Generally, lens pins106and108can be configured to receive any of a variety of connectors, such as, for example, MU, SC, LC, ST, and FC connectors. In some embodiments, a lens pin is configured to compatibly receive two or more different types of connectors.

Generally, a HBA can be any type of printed circuit board implemented as a suitable connector interface for use with a computer system, wherein the connector interface may take the form of, for example, a peripheral component interconnect (“PCI”) card having edge connectors configured and arranged to interface with a desktop computer system The connector interface may alternatively take the form of, for example, a printed circuit board with a serial or parallel port, or a Personal Computer Memory Card International Association (“PCMCIA”) standard card. Note that as used herein, “connector interface” generally refers to a PCB or other device that acts as an interface between an optical component, such as the modular optical device150, and a host system such as a laptop computer, desktop computer, or portable computing systems such as personal digital assistants (“PDA”).