This invention relates to transmission of signals by fiber optic cables, and in particular, it relates to connectors between fiber optic cables and USB (Universal Serial Bus) ports, such as USB-C ports, and USB extenders employing such connectors.
Due to their large bandwidth and long reach, fiber optic cables are widely used to transmit data. For example, fiber optic cables may be used to transmit video, audio and other signal between video sources (such as video players, video signal switches, computers, etc.) and display devices (such as digital televisions, monitors, etc.). On the other hand, electronic devices are typically equipped with ports for data communication, where the ports typically comply with various industry standards such as USB (Universal Serial Bus), HDMI (High Definition Multimedia Interface), DP (DisplayPort), DVI (Digital Visual Interface), VGA (Video Graphics Array), etc. Connectors between fiber optic cable and HDMI, DP, DVI, and Keystone ports have been available.
Embodiments of the present invention provide a USB-C connector for fiber optic cable. To overcome challenges arising from various requirements of the USB-C standard, the USB-C connector employs a two-section dongle form to ensure reliability and high performance.
Additional features and advantages of the invention will be set forth in the descriptions that follow and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims thereof as well as the appended drawings.
To achieve the above objects, the present invention provides a signal connector, which includes: a plug section, a dongle assembly, and a connection cable assembly connecting the plug section to the dongle assembly. The plug section includes a plug head having a first plurality of pins and a second plurality of pins, an optical transceiver configured to convert signals between electrical signals and optical signals, and control circuitry configured to control the optical transceiver, the control circuitry being electrically coupled to the first plurality of pins of the plug head. The dongle assembly includes an optical fiber connector and at least one signal processing chip. The connection cable assembly includes a first plurality and a second plurality of optical fibers connecting the optical transceiver of the plug section to the optical fiber connector of the dongle assembly, a first plurality of electrical conductor wires connecting the control circuitry of the plug section to the signal processing chip of the dongle assembly, and a second plurality of electrical conductor wires connecting the second plurality of pins of the plug head of the plug section to the signal processing chip of the dongle assembly. The at least one signal processing chip is configured to process electrical signals transmitted between the second plurality of pins of the plug head and the control circuitry.
In some embodiments, the plug head is a USB-C(Universal Serial Bus-C) plug head and has physical dimensions less than 12.35 mm in width and less than 6.5 mm in height. The first plurality of pins of the USB-C plug head are SuperSpeed signal pins and the second plurality of pins of the USB-C plug head are non-SuperSpeed signal pins. The control circuitry is configured to: control the optical transceiver to convert electrical signals received from the SuperSpeed signal pins of the USB-C plug head to optical signals to be transmitted to the first plurality of optical fibers; control the optical transceiver to convert optical signals received on the first plurality of optical fibers to electrical signals and to transmit the electrical signals to the SuperSpeed signal pins of the USB-C plug head; control the optical transceiver to convert electrical signals received from the signal processing chip via the first plurality of electrical conductor wires to optical signals to be transmitted to the second plurality of optical fibers; and control the optical transceiver to convert optical signals received on the second plurality of optical fibers to electrical signals and to transmit the electrical signals to the signal processing chip via the first plurality of electrical conductor wires.
In some embodiments, the signal processing chip is configured to perform signal multiplexing and demultiplexing and to control signal transmission directions on the optical fibers.
In some other embodiments, the plug head is a USB-A (Universal Serial Bus-A), miniDP (miniDisplayPort), HDMI (High Definition Multimedia Interface), DVI (Digital Visual Interface), or Thunderbolt plug head.
In another aspect, the present invention provides a signal extender, which includes the signal connector described above and a fiber optic cable connected to the signal connector. In some embodiments, another signal connector is connected to the other end of the fiber optic cable. The two connectors may comply with the same or different interface standards, such as USB-C or other standards. In some embodiments, the signal connectors and the fiber optic cable are connected to each other by MPO (Multi-fiber Push On) connectors.
In another aspect, the present invention provides a signal transmitter and receiver device, which includes an enclosure, and a first and a second printed circuit boards disposed within the enclosure. The first printed circuit board has an electrical signal connector, an optical transceiver, and control circuitry mounted on it, wherein the electrical signal connector has a first plurality of pins and a second plurality of pins, the optical transceiver is configured to converts between electrical signals and optical signals, the control circuitry is configured to control the optical transceiver, and the control circuitry is electrically coupled to the first plurality of pins of the electrical signal connector. The second printed circuit board has at least one signal processing chip mounted on it. A bus electrically connects the first and second printed circuit boards, and includes a first plurality of electrical conductors connecting the control circuitry on the first printed circuit board to the signal processing chip on the second printed circuit board, and a second plurality of electrical conductors connecting the second plurality of pins of the electrical signal connector on the first printed circuit board to the signal processing chip on the second printed circuit board. An optical fiber connector is also mounted within the enclosure. A plurality of optical fibers are disposed within the enclosure and connect the optical transceiver on the first printed circuit board to the optical fiber connector. The at least one signal processing chip is configured to process electrical signals transmitted between the second plurality of pins of the electrical signal connector on the first printed circuit board and the control circuitry.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
USB-C Connector
As the current data rates for USB-C and USB 4 signals are above 10 Gbps, copper cables are not able to support transmission distances longer than about 15 feet. Transmission by fiber optic cable often thus becomes highly desirable for longer distances. Therefore, there is a need to provide USB-C connectors that can connect fiber optic transmission cables to USB-C ports on electronic devices. Such a connector includes an optical transceiver that converts signals between electrical signals and optical signals, and digital signal processing chips that process the signal being transmitted. However, USB-C connector plug (the male connector) has a physical dimension requirement of 12.35 mm in maximum width and 6.5 mm in maximum height (width are height are dimensions perpendicular to the longitudinal direction of the plug). Due to this small physical size, issues arise that hinder the implementation of signal processing chips inside the plug. For example, the signal processing chips may be too large to fit inside the plug. Also, heat generated by the signal processing chips may heat up the plug, which may reduce the performance of the optical transceiver components inside the plug, in particular, the lasers.
To solve these problems, embodiments of the present invention provide a USB-C connector for fiber optic cable that employs a two-section dongle form, with the signal processing chips being located in the second section of the dongle. For convenience, in this disclosure, the second section is referred to as the dongle section and the first section is referred to as the plug section. As shown in
The plug section 10 has a USB-C plug head 12 at the first end of the connector 1, configured to be inserted into a USB-C port of a first external device such as a USB host (see
Each of the plug section 10, the dongle section 20 and the cable 30 has an enclosure (i.e. a plastic housing or cover) that encloses the internal components. Preferably, the cable 30 is formed integrally with the plug section 10 and dongle section 20, i.e. they are joined to each other permanently and cannot be separated during normal use.
The structure of the USB-C connector 1 is schematically illustrated in more detail in
The plug section 10 further includes control circuitry 16 which includes, for example, a driver circuit for controlling the light emitters and a transimpedance amplifier (TIA) for amplifying electrical signals generated by the light detectors. The driver circuit and transimpedance amplifier are respectively coupled to the light emitters and light detectors by electrical connections. The control circuitry 16 is electrically coupled to a first group of pins 13-1 of the USB-C plug head 12. The control circuitry 16 is also electrically coupled to the signal processing chips 24 in the dongle section 20 by a first group of electrical conductor wires 33 of the cable 30. The signal processing chips 24 are directly electrically coupled to a second group of pins 13-2 of the USB-C plug head 12 by a second group of electrical conductor wires 34 of the cable 30. Note that in
In preferred embodiments, the dongle section 20 contains no optical-electrical conversion components, and the plug section 10 contains no digital signal processing components (here, digital signal processing is understood to refer to manipulation of digital signals in the digital form; the functions of the driver and TIA are not digital signal processing). In some embodiments, the dongle section 20 may include a power supply connector (not shown) to receive an external power supply to allow power injection if desired. In preferred embodiments, the dongle section 20 has no other signal connection besides the fiber connector 22, the cable 30, and the optional power supply.
A standard USB-C interface, with a 24-pin double-sided layout, includes four SuperSpeed differential pairs TX1+, TX1−, RX1+, RX1−, TX2+, TX2−, RX2+, RX2−. In applications, the SuperSpeed signals may be used to transmit video signals or other data. In the plug section 10, the control circuitry 16 is directly coupled to the SuperSpeed pins of the USB-C plug head 12, which are indicated by reference symbol 13-1 in
More specifically, in the transmitting direction, the SuperSpeed electrical signals received from the first external device on pins 13-1 are fed to the driver circuit of the control circuitry 16, which drives the light emitters accordingly to generate optical signals on the first group of optical fibers 31. The optical signals on optical fibers 31 are coupled to the external fiber optic cable 2 by the fiber connector 22. In the receiving direction, the SuperSpeed optical signals on the first group of optical fibers 31 received via external cable 2 are converted to electrical signals by the light detectors of the optical transceiver 14 and amplified by the TIA of the control circuitry 16, and directly fed to the SuperSpeed pins 13-1 of the USB-C plug head 12.
The standard USB-C interface also includes various high speed (less than 1.5 Gbps) pins and other signal pins including the power wire. For convenience, these signals are collectively referred to as the non-SuperSpeed signals in this disclosure, and the corresponding pins of the USB-C plug head 12 are indicated by reference symbol 13-2. These non-SuperSpeed signals need to be processed between the pins 13-2 and the control circuitry 16. In embodiments of the present invention, the signal processing is performed by the chips 24 located in the dongle section 20, and routed between the plug section 10 and the dongle section 20 by the conductor wires 33 and 34 of the cable 30.
More specifically, in the transmitting direction, the non-SuperSpeed signals received on pins 13-2 are transmitted directly to the chips 24 of the dongle section 20 by the second group of conductor wires 34. Preferably, the second group of conductor wires 34 include sufficient number of wires to separately connect each one of the pins 13-2 to the signal processing chips 24. The signals are processed by the chips 24, and the processed signals are transmitted from the chips to the control circuitry 16 of the plug section 10 by the first group of conductor wires 33 of the cable 30. The driver in the control circuitry 16 drives the light emitters accordingly to generate optical signals on the second group of optical fibers 32. The optical signals on optical fibers 32 are coupled to the external fiber optic cable 2 by the fiber connector 22. In the receiving direction, after the optical signals on the second group of optical fibers 32 are converted to electrical signals by the light detectors of the optical transceiver 14 and amplified by the TIA of the control circuitry 16, the control circuitry sends the electrical signals to the signal processing chips 24 of the dongle section 20 via the first group of conductor wires 33. The signal processing chips 24 processes the signals, and transmits the resulting processed signals directly to the second group of pins 13-2 of the USB-C plug head 12 via the second group of conductor wires 34 of the cable 30.
Preferably, there is a one-to-one correspondence between the first group of conductor wires 33 and the second group of optical fibers 32, so that the plug section 10 can directly perform the optical-electrical and electrical-optical conversions for signals on each conductor wire 33 and corresponding optical fiber 32 without further signal processing (e.g. without signal multiplexing and demultiplexing). If the conductor wires 33 use pairs of differential wires, then there is preferably a one-to-one correspondence between the pairs of conductor wires 33 and the optical fibers 32
It can be seen from the above descriptions that in the USB-C connector 1 according to embodiments of the present invention, the SuperSpeed signals are directly converted to and from optical signals, without being transmitted as electrical signals over a conductor wire of the cable 30. This avoids potential signal degradation by the conductor wire, especially when the SuperSpeed signal speed is further increased from the current speed (5 Gbps) to 20 Gbps or higher in future standards. The further speed increase of the SuperSpeed signal will not change the working principle of the USB-C connector 1 described here. As to the high speed signals and other non-SuperSpeed signals, they can be properly transmitted between the plug section 10 and the dongle section 20 over the conductor wires 33, 34 of the cable 30 without degradation.
The processing of the non-SuperSpeed signals by the signal processing chips 24 includes one or more of the following.
Signal multiplexing and demultiplexing: In the USB-C connector 1, signals on all of the non-SuperSpeed pins 13-2 are multiplexed onto a few (e.g., two to four) optical fibers 32 for transmission over the external fiber optic cable 2 to the remote end. This is possible because of the higher bandwidth of the optical fibers. In the receiving direction, the optical signals on the second group of optical fibers 32, which are multiplexed signals that have been generated (for example by a USB-C connector 1′) at the remote end (see
Regulation of bus utilization (i.e. TX/RX directionality): USB-C standard permits bi-directional data transmission. For example, the D+, D− signal may be bi-directional. Because each optical fiber can transmit signals only in one direction at any given time, the two USB-C connectors 1, 1′ at the two ends of the external fiber optic cable 2 use one of the USB-C signals, such as the Configuration Channel (CC) signal, to dynamically set the transmission direction on each optical fiber. The signal processing chips 24 processes the Configuration Channel signal to set or obtain information regarding the transmission directions on each of the optical fibers. Based on this information, the signal processing chips 24 transmits control commands to the control circuitry 16 of the plug section 10 via a conductor wire of the cable 30, for example one of the first group of conductor wires 33 or a separate conductor wire, to instruct the control circuitry 16 to either transmit or receive signals on each optical fiber.
The signal processing chips 24 may also performs other desired signal processing functions.
The signal processing chips 24 may require an additional power supply to support their power up operation. In a situation where two devices are connected with a metal-wire cable, when the two devices are turned on, the metal wires between the devices will pass signals instantly. In a signal connector such as the USB-C connector 1 shown in
Although the USB-C connector 1 shown in
To summarize, embodiments of the present invention provide a USB-C connectors employing a multi-section dongle form, where the plug section contains only the optical transceiver and its control circuit to perform optical-electrical signal conversion without other signal processing chips, and the dongle assembly (one or two dongle sections) contains the signal processing chips and fiber connector but no optical transceiver. The dongle assembly is connected to the plug section by a suitable connection cable assembly (one or two cables).
The structures of the multi-section dongle form connector 1 described here may be used to implement other connectors such as USB-A connectors, miniDP connectors, HDMI connectors, Thunderbolt connectors, etc. A USB-A connector 1A is illustrated as an example in
USB-C Extender, Other Extenders and Adapters
The configuration shown in
This USB-C extender is transparent, in that it transmits signals between the two ends without storing any data, and it does not interpret the meaning of the data being transmitted.
In an alternative embodiment, the other USB-C connector 1′ may have a USB-C receptacle (female connector), rather than a USB-C plug (male connector), at its end. In this alternative structure, the connector 1′ may have a two-section dongle form, or a one-section form if its physical size can accommodate the signal processing chips without adversely affecting the performance of the optical transceiver.
In an alternative to the configuration shown in
In the fiber optic USB-C extender shown in
As pointed out above, because of the much higher bandwidth of the optical fibers, a small number, such as two to four, optical fibers can carry all of the non-SuperSpeed USB-C signals in a multiplexed manner. Thus, the cable 30 and the external fiber optic cable 2 may each include six to eight optical fibers in total. The external fiber optic cable 2 may alternatively have a different number of optical fibers as the cable 30.
To summarize, the fiber optic USB-C extender shown in
More generally, embodiments of the present invention provide a fiber optic signal extender or adapter, formed by a fiber optic cable of an extended length (e.g. tens or hundreds of feet) and two electrical signal connectors at each end, the two connectors preferably complying with industry standards (same or different at the two ends), where at least one of the two connectors has a multi-section dongle form described above.
Stack-Up Modules
The optical and electrical signal handling and routing scheme used in the USB-C connector 1 can be applied to signal transmitters and receivers of other physical form factors to provide various benefits. One example is a signal transmitter and receiver device suitable for use in a stack-up configuration, shown in
More specifically, the first PCB 401 supports one or more sets of an electrical signal connector 404 (e.g. an HDMI port), a corresponding optical transceiver 405 (including optical coupling components), and corresponding control circuitry 406. The second PCB 402 supports signal processing chips 407, as well as various other electrical signal connectors such as RS-323, IR, USB, RJ45, ARC (Audio Return Channel), and power supply connector. The electrical connections among these components are omitted in
In terms of their functions, the electrical signal connector 404 is similar to the USB-C plug head 12 of the USB-C connector 1, the optical transceiver 405 is similar to the optical transceiver 14, the control circuitry 406 is similar to the control circuitry 16, the signal processing chips 407 are similar to the signal processing chips 24, the fiber connector 408 is similar to the fiber connector 22, the bus 403 is similar to the conductor wires 33, 34, and the optical fibers between the optical transceiver 405 and fiber connector 408 are similar to the optical fibers 31, 32. The optical and electrical signal routing among the various components is also similar to that in the USB-C connector 1. Therefore, further descriptions are omitted. Of course, the signal processing chips 407 may also perform other signal processing functions related to the other signals handled by the device 4.
Using the configuration shown in
Locating the fiber connector (MPO) 408 at one end of the device 4 may facilitate easy plug and pull of the external fiber cable, and also saves PCB real estate (the fiber connector is not mounted on the main PCB). The smaller PCB 401 may be advantageously located at the other end of the device 4 to allow sufficient space inside the enclosure for the fiber between the electrical signal connector 404 and fiber connector (MPO) 408 to bend.
While two HDMI ports are shown in the example of
Dongle Form for Wireless Chipsets
The two-section dongle form may be used in other pluggable devices. For example, some pluggable devices include wireless chipsets for wireless communication. Sometimes, for various reasons, it is undesirable for the wireless chipsets to be physically located close to the computer or other instrument that the pluggable device is plugged into. In such cases, the pluggable device may use a two-section dongle form, with the wireless chipsets located in the dongle section and physically separated from the plug section by a small distance, so that both sections can function properly. This configuration may be used in USB-C, DP, HDMI, etc. connectors, or any other pluggable devices. Note that such pluggable devices are not limited to optical fiber related applications, but have general applicability.
It will be apparent to those skilled in the art that various modification and variations can be made in the USB-C connector, USB-C extender, other extenders, adapters, and stack up modules of the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover modifications and variations that come within the scope of the appended claims and their equivalents.