Avionics pluggable active optical connector

Abstract

To eliminate drawbacks associated with the design and re-design of line replaceable units (LRUs) having a built-in transceiver.SOLUTION: A pluggable active optical connector (14) is modular with one or more channels and converts electrical signals to optical signals and vice versa. On one side, the apparatus has a pluggable electrical interface (16) to a line replaceable unit (LRU) (10a); and, on the other side, the apparatus has a pluggable optical interface (18) to an aircraft fiber optic wiring bundle (20a, 20b). The apparatus is pluggable to different types of LRUs, including rack-mounted and bolted-down LRUs. The apparatus includes electronic and optical communication components sufficient to enable electrical / optical conversion totally within a standard-sized aircraft connector. The apparatus is adaptable to various data communication protocols and has the flexibility to be used in both single-fiber and dual-fiber bidirectional data links.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The technology disclosed herein relates generally to fiber optic networks that enable communication between electronic components, and more particularly to electrical avionics systems connected together by optical avionics data buses. [Background technology]

[0002] The use of fiber optic cables instead of electrical wiring in high speed avionics data networks can significantly reduce the weight, cost, electromagnetic interference, and complexity of installing electrical wiring. Linear replaceable units (LRUs) (such as avionics computers and sensor units) typically include a housing that contains a transceiver to enable fiber optic communication with other LRUs. Optical connectors on the LRU housing allow an external fiber optic cable to be connected to the LRU.

[0003] More specifically, each LRU connected to the optical avionics data bus typically includes an optical-to-electrical media converter having an electrical-to-optical transmitter and an optical-to-electrical receiver (collectively referred to hereinafter as an "optical-to-electrical bidirectional transceiver") to enable fiber optic communication with other LRUs. The electrical-to-optical transmitter converts electrical signals to optical signals, and the optical-to-electrical receiver converts the optical signals back to electrical signals. Optical connectors on the housing of the LRU enable connection of fiber optic cables to the LRU.

[0004] Furthermore, a typical aircraft assembly process requires a manufacturing break (in-line connector) between the LRU and the aircraft wiring bundle. When an existing opto-electrical LRU is removed from the rack, the optical contacts are exposed to a dust and moisture environment and require cleaning and inspection before being reinserted into the rack. For the LRU to interface with the aircraft's optical fiber, suppliers must acquire new capabilities to redesign and incorporate new transceivers, optical wiring, and optical connectors into the LRU. The learning curve is difficult and the cost to design, manufacture, and warranty a new LRU with an optical interface is high. Furthermore, the optical design of the new LRU is not consistent between LRUs and suppliers because the aircraft manufacturer does not dictate the internals of the LRU, but can only define the optical interface to the aircraft wiring.

[0005] It is believed that a design of electrical avionics systems connected together by an optical avionics data bus, but which does not suffer from the drawbacks discussed above, would be beneficial for a variety of reasons, including eliminating the costs associated with designing and redesigning LRUs that incorporate transceivers. Summary of the Invention

[0006] The subject matter disclosed in greater detail below relates to a device that is modular with one or more channels and configured to function as a pluggable active optical connector (hereinafter "PAOC") that converts electrical signals to optical signals and vice versa. The PAOC has a pluggable electrical interface to a line replaceable unit (LRU) on one side, and the device has a pluggable optical interface to the aircraft's fiber optic wiring bundle on the other side. The PAOC can be plugged into various types of LRUs, including rack-mounted and bolt-down LRUs. The PAOC contains sufficient electronic and optical communication components to enable electrical-to-optical conversion entirely within the aircraft connector. In addition, the device is adaptable to various data communication protocols and can be used with either single-fiber or dual-fiber connectors. It also has the flexibility to be used for directional data links. This type of pluggable active optical connector eliminates the drawbacks associated with designing and redesigning LRUs with built-in transceivers.

[0007] As used herein, the term "pluggable," when used as an adjective to describe the capability of a first component, means that the component can be mated to and later disconnected from a second component by inserting a male portion (e.g., a pin or plug) of one of the first and second components into a respective female portion (e.g., a receptacle or socket) of the other of the first and second components. For example, a PAOC may have electrical pins that are inserted into electrical sockets of an LRU mating connector, or the PAOC may have electrical sockets into which electrical pins of an LRU mating connector are inserted. In either case, the PAOC "plugs into" the LRU mating connector.

[0008] Various embodiments of the pluggable active optical connector are described in greater detail below, one or more of which may be characterized by one or more of the following aspects.

[0009] One aspect of the subject matter disclosed in detail below is a pluggable active optical connector comprising a connector housing, a printed circuit board contained within the connector housing, a plurality of electrical connectors electrically coupled to and supported by the printed circuit board, a bidirectional optical subassembly comprising a laser device and a photodetector electrically coupled to the printed circuit board, and a housing mounted on the printed circuit board and comprising a first receptacle configured to accommodate the bidirectional optical subassembly and a second receptacle configured to receive one end of a termination piece for terminating an optical cable. The first laser device is electrically coupled to a first pair of electrical connectors of the first plurality of electrical connectors and is arranged to transmit light through the housing to an end of a first optical fiber in response to an electrical signal received through the first pair of electrical connectors of the first plurality of electrical connectors. The first photodetector is electrically coupled to a second pair of electrical connectors of the first plurality of electrical connectors and is arranged to transmit an electrical signal to the second pair of electrical connectors of the first plurality of electrical connectors in response to receiving light from the end of the first optical fiber.

[0010] Another aspect of the subject matter disclosed in detail below is a data transmission system comprising an optical fiber network, a plurality of electronic devices, a plurality of mating connectors respectively attached to and electrically coupled to the plurality of electronic devices, each having a plurality of electrical connectors, and a plurality of pluggable active optical connectors respectively attached to and electrically coupled to the plurality of mating connectors and optically coupled to the optical fiber network, each of the plurality of pluggable active optical connectors comprising a respective optical-electrical bidirectional transceiver and a plurality of electrical connectors respectively electrically coupled to the electrical connectors of the respective mating connectors. According to one proposed embodiment, the electronic devices are line replaceable units installed in an aircraft.

[0011] A further aspect of the subject matter disclosed in detail below is a method for assembling an avionics data transmission system, comprising the steps of: (a) connecting a first plurality of electrical connectors to circuitry on a printed circuit board; (b) connecting a laser device and a photodetector of an optical subassembly of an optical-electrical bidirectional transceiver to circuitry on the printed circuit board; (c) positioning an end of a fiber optic cable of an onboard optical fiber network of an aircraft in a position facing the optical subassembly of the optical-electrical bidirectional transceiver; and (d) connecting the first plurality of electrical connectors to circuitry on a printed circuit board. and connecting the connector to a second plurality of electrical connectors of a mating connector mounted to a line replaceable unit on board the aircraft.

[0012] According to one embodiment of the method described in the immediately preceding paragraph, step (c) includes terminating an end of the fiber optic cable at the termination portion and inserting the termination portion into a housing mounted on the printed circuit board until an end face of the fiber optic cable is within a predetermined distance of an optical subassembly of the optical-electrical bidirectional transceiver and optically coupled to the optical subassembly of the optical-electrical bidirectional transceiver. Additionally, step (d) includes aligning the first plurality of electrical connectors with the second plurality of electrical connectors and moving the printed circuit board toward the line replaceable unit while maintaining the alignment of the first and second plurality of electrical connectors.

[0013] Other aspects of the pluggable active optical connector are disclosed below. [Brief description of the drawings]

[0014] The features, functions, and advantages discussed in the preceding sections may be achieved independently in various embodiments or may be combined in yet other embodiments. Various embodiments are described below with reference to the drawings for purposes of illustrating the above-mentioned and other aspects. Any of the figures briefly described in this section are not drawn to scale.

[0015] [Figure 1] 1 is a schematic diagram illustrating a three-dimensional cutaway view of an aircraft on-board data processing system, the data processing system including an optical data communications network. [Diagram 2] 2 is a schematic diagram of a typical opto-electrical LRU having an internal transceiver that can optically couple to a fiber optic cable of an optical avionics data bus when the LRU-side connector and the aircraft-side connector are mated (the connector is shown unmated in FIG. 2 ). [Diagram 3] 3 is a schematic diagram illustrating an electrical LRU that can receive data from and transmit data to the fiber optic cable of an optical avionics data bus via a PAOC when the LRU-side connector and an aircraft-side pluggable active optical connector are mated according to one embodiment (the connector is shown unmated in FIG. 3 ). [Figure 4] FIG. 2 is a block diagram identifying some components of an optical-electrical bi-directional transceiver according to one proposed embodiment. [Diagram 5] 1 is a simplified diagram depicting a cross-sectional view of a termination / receptacle assembly according to one embodiment. [Figure 6] 6 is a schematic diagram illustrating a side view of a portion of a fiber optic cable that can be inserted into the termination shown in FIG. 5 to optically couple the optical fiber to a transmit / receive TO can. [Figure 7-8] 1A-1C are schematic diagrams each showing a three-dimensional view of an aligned but unmated LRU mating connector and a pluggable active optical connector, respectively. [Figure 9A] 9 is a schematic diagram illustrating a side view of the LRU mating connector shown in FIGS. 7 and 8. FIG. [Figure 9B] 9 is a schematic diagram illustrating a side view of the pluggable active optical connector shown in FIGS. 7 and 8. FIG. [Fig. 10A-11A] 9B is a schematic diagram showing a top view and a side view, respectively, of the LRU mating connector shown in FIG. 9A excluding the housing (shown in dashed lines). [Fig. 10B-11B]9C are schematic diagrams illustrating top and side views, respectively, of the pluggable active optical connector shown in FIG. 9B excluding the connector housing (shown in dashed lines). [Figure 12A] 9B is a schematic diagram illustrating a three-dimensional view of the electrical interfaces of the LRU mating connector shown in FIG. 9A excluding the housing (shown in dashed lines) and the wiring connecting the electrical interfaces. [Figure 12B] 9C is a schematic diagram depicting a three-dimensional view of the assembled internal components of the pluggable active optical connector shown in FIG. 9B excluding the connector housing (shown in dashed lines). [Figure 13] 12C is a schematic diagram depicting a side view of the assembled internal components of the pluggable active optical connector shown in FIG. 12B. [Figure 14-15] 12C are schematic diagrams each representing a three-dimensional view of the assembled internal components of the pluggable active optical connector shown in FIG. 12B. [Figure 16] 4 is a flowchart identifying steps of a method for assembling an avionics data transmission system according to one embodiment. [Figure 17] 17 is a schematic diagram of an electrical LRU capable of receiving data from and transmitting data to a fiber optic cable of an optical avionics data bus when the LRU-side connector and the aircraft-side pluggable active optical connector are electrically coupled using a short jumper cable in accordance with an alternative embodiment, with the mating electrical pins and sockets of the jumper cable not shown for simplicity (the connector and jumper cable are shown unmated in FIG. 17 ). [Figure 18] 18 is a schematic diagram illustrating an electrical LRU that can receive data from and transmit data to an optical avionics data bus fiber optic cable when the LRU-side connector is mated with an aircraft-side pluggable active optical connector with a pigtail secured by epoxy in accordance with a further alternative embodiment (the connector is shown unmated in FIG. 18 ). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Reference will now be made to the drawings, in which similar elements are designated by the same reference numerals in different figures.

[0017] Exemplary embodiments of pluggable active optical connectors are described in some detail below. However, not all features of an actual implementation are described herein. In developing such an actual implementation, one of ordinary skill in the art will appreciate that numerous implementation-specific decisions must be made to achieve the developer's particular goals, which may vary from implementation to implementation, including compliance with system-related and business-related constraints. Moreover, one of ordinary skill in the art will appreciate that such development efforts may be complex and time-consuming, but would nevertheless be considered a routine undertaking for one of ordinary skill in the art having the benefit of this disclosure.

[0018] Various embodiments of optical fiber networks for enabling optical communications between line replaceable units on an aircraft are described in detail below for illustrative purposes, however, the optical fiber network embodiments disclosed herein are not limited to aircraft environments, but rather may be utilized in other types of vehicle-mounted optical fiber networks or other types of optical fiber networks (e.g., long-haul ground, data center, and fiber-to-the-home / office applications).

[0019] Fiber optic networks have the advantages of higher speed, lighter weight, and less susceptible to electromagnetic interference compared to copper wire networks. Many types of commercial aircraft have fiber optic networks to reduce size, weight, and power. To achieve communication in avionics systems, it is common to connect multiple line replaceable units (LRUs) together. For example, multiple LRUs at the front of a vehicle (e.g., an aircraft) are connected to multiple LRUs at the rear of the vehicle via an avionics data bus.

[0020] FIGURE 1 illustrates a network environment 100 that includes an aircraft 102. The aircraft 102 is an example of a platform in which the connectors disclosed herein may be used. In the example illustrated in FIGURE 1, the aircraft 102 includes a right wing 104 mounted to a fuselage 108. The aircraft 102 has a front wing 104 and a left wing 106. Additionally, the aircraft 102 includes an engine 110 mounted on the right wing 104 and an engine 112 mounted on the left wing 106. Additionally, the aircraft 102 has a nose region 114 and a tail region 116. The tail region 116 includes a starboard horizontal stabilizer 118, a left horizontal stabilizer 120, and a vertical stabilizer 122.

[0021] The aircraft 102 shown in FIG. 1 further includes an on-board data communication and processing system 124 that includes an optical fiber network 126 and a number of devices 127, such as flight deck displays 128, flight control computers 130, and other components, connected to (and even optically coupled with) the optical fiber network 126. The other types of devices 127 can take the form of LRUs 132, 134, 136, 138, 140, 142, 144, 146, and 148. These LRUs can take a variety of forms. For example, the LRUs can be computers, sensors, in-flight entertainment systems, and other suitable types of devices. The devices 127 use electrical signals internally, and thus the optical signals carried by the optical fiber network 126 are typically converted to electrical signals by using optical-electrical media converters (not shown in FIG. 1). These optical-electrical media converters (hereinafter, "optical-electrical bidirectional transceivers") can be internal or external to the LRUs.

[0022] For LRUs with one or more opto-electrical transceivers integrated inside the LRU housing (hereinafter "opto-electrical LRUs"), the opto-electrical LRUs may be mounted in an on-board rack of an aircraft by a mechanical assembly that provides support and automatic positioning of the LRU. Each opto-electrical LRU includes an internal opto-electrical bi-directional transceiver that optically couples to an optical avionics data bus of optical fiber network 126 by a mating connector that is mechanically coupled to the LRU housing. The mating connector provides optical connection to aircraft systems and structural support for the LRU.

[0023] 2 illustrates a typical optical-electrical LRU 10a having an LRU housing 12, a backplane connector 14 mechanically coupled to and housed within the LRU housing 12, a printed circuit board 8a mechanically coupled to the optical backplane connector 14, and an LRU mating optical connector 16 mechanically coupled to the LRU housing 12. In the example illustrated in FIG. 2, the LRU mating optical connector 16 has a pair of terminations 26a and 26b that terminate respective ends of fiber optic cables 22a and 22b disposed within the LRU housing 12 and on one side of the backplane connector 14. The other ends of the fiber optic cables 22a and 22b are optically coupled to respective ends of fiber optic cables 24a and 24b within the LRU housing 12 and on the other side of the backplane connector 14 by respective optical connectors 30a and 30b. The optical connectors 30a and 30b are affixed to the backplane connector 14.

[0024] The opto-electrical LRU 10a shown in Figure 2 further includes a pair of opto-electrical bidirectional transceivers 2a and 2b (two for redundancy) mounted on and electrically coupled to the printed circuit board 8a. Each of the opto-electrical bidirectional transceivers 2a and 2b includes an electrical-optical transmitter and an opto-electrical receiver (not shown in Figure 2). The opto-electrical bidirectional transceiver 2a is optically coupled to the other end of the fiber optic cable 24a, and the opto-electrical bidirectional transceiver 2b is optically coupled to the other end of the fiber optic cable 24b.

[0025] 2 further illustrates aircraft harness optical connector 18 having a pair of terminations 28a and 28b that terminate respective ends of fiber optic cables 20a and 20b of a fiber optic network at a location external to opto-electrical LRU 10a. When LRU mating optical connector 16 and aircraft harness optical connector 18 are mated, Fiber optic cables 20a and 20b are optically coupled to optical-electrical bidirectional transceivers 2a and 2b, respectively, within optical-electrical LRU 10a.

[0026] According to the configuration shown in Figure 2, the optical-electrical bidirectional transceivers 2a and 2b are mounted on a printed circuit board 8a, and the associated fiber optic cables and optical connectors located in each LRU are variously customized by different suppliers. Such a configuration also requires a fiber management device for controlling the bend radius and the optical connectors at the LRU interface.

[0027] In contrast to the opto-electrical LRU 10a shown in Figure 2, Figure 3 shows an electrical LRU 10b (without an internal opto-electrical transceiver) optically coupled to fiber optic cables 20a and 20b by a pluggable active optical connector 32 external to the electrical LRU 10b. As used herein, the term "active" means that the optical connector has an opto-electronic component (e.g., an optical-electrical bidirectional transceiver). The pluggable active optical connectors (PAOCs) disclosed herein are designed to be used with electrical LRUs that do not have internal opto-electrical transceivers.

[0028] The electrical LRU 10b shown in Figure 3 has an LRU housing 12, a printed circuit board 8a mounted inside the LRU housing 12, and an LRU mating electrical connector 34 mechanically coupled to the LRU housing 12. In the example shown in Figure 3, the LRU mating electrical connector 34 is an electrical interface having a number of electrical pins 62 on the wiring bundle side and electrical wires 64 on the LRU side. There is a one-to-one correspondence of the electrical pins 62 to the electrical wires 64. Each electrical pin 62 is electrically conductively connected to a respective electrical wire 64 to form a number of parallel electrical conductors that carry electrical signals representing information received from or transmitted to other LRUs over the fiber optic network.

[0029] Figure 3 further illustrates a pluggable active optical connector 32 having a pair of terminations 28a and 28b that terminate respective ends of fiber optic cables 20a and 20b of a wire bundle assembly at a location external to electrical LRU 10b. Pluggable active optical connector 32 includes a connector housing 38 having a plurality of electrical sockets 60 on the LRU side for receiving a plurality of electrical pins 62 upon mating of LRU mating electrical connector 34 with pluggable active optical connector 32. Pluggable active optical connector 32 further includes a pair of bidirectional optical-electrical transceivers (not shown in Figure 3, but which may each have the structure shown in Figure 4). When the LRU mating electrical connector 34 and the pluggable active optical connector 32 are mated (FIG. 3 shows these components in an unmated state), the electrical LRU 10b is electrically coupled to an optical-electrical bidirectional transceiver integrated into the pluggable active optical connector 32 via the electrical socket 60 and a printed circuit board (not shown in FIG. 3).

[0030] 4 is a block diagram identifying some components of an optical-electrical bidirectional transceiver 2 according to one proposed embodiment. The optical-electrical bidirectional transceiver 2 has a single-fiber full-duplex bidirectional transceiver design in which the optical-electrical bidirectional transceiver 2 transmits light having a first wavelength λ1 and receives light having a second wavelength λ2, different from the first wavelength λ1, over the same optical fiber cable 28 (not shown in FIG. 4, but see optical fiber 20a or 20b in FIG. 8). The optical-electrical bidirectional transceiver 2 is implemented as a bidirectional optical subassembly mounted on a printed circuit board 40. The printed circuit board 40 further includes various electrical components mounted on the printed circuit board 40 and printed circuitry that connects the electrical components to each other and to the terminals.

[0031] The two-wavelength single-fiber optical-electrical bidirectional transceiver 2 shown in FIG. 4 includes a laser device 44 and a photodetector 48. The laser device 44 is driven to emit light of wavelength λ1 by a laser driver 42 in response to receiving at a data input terminal 56 a differential transmit signal from a corresponding column line replacement unit (not shown) via a transmit electrical signal line (not shown in FIG. 4). (As used herein, the term "wavelength" in the context of coherent laser light means the central wavelength of a laser light having a narrow spectral width.) The laser driver 42 includes an electrical circuit that converts the electrical differential signals into electrical digital signals representing data to be transmitted by the laser device 44. Conversely, the photodetector 48 receives light of wavelength λ2, converts the detected light into an electrical signal, and provides the electrical signal to a receiver circuit that includes a transimpedance amplifier 50 that amplifies the detector signal and a limiting amplifier 52 that digitizes the output signal. The receiver circuit converts the electrical signals into digital electrical differential receive signals representing the receive data. The electrical differential receive signals are transmitted to other circuits within the column line replaceable unit via data output terminals 54 and electrical receive signal lines not shown in FIG.

[0032] In the example shown in FIG. 4, the bidirectional transceiver 2 includes a laser device 44 and a photodetector 48. The laser device 44 can be realized with a single-mode distributed feedback laser, a multimode Fabry-Perot laser, or a vertical cavity surface emitting laser for high optical output and low modal noise. The photodetector 48 can be realized with a high responsivity p-type intrinsic-n-type (PIN) photodiode or an avalanche photodiode to provide high receiver sensitivity. The bidirectional transceiver 2 shown in FIG. 4 further includes an LC receptacle sized and configured to receive an end of an optical fiber (not shown in FIG. 4, but see optical fiber 20a or 20b in FIG. 8).

[0033] The opto-electrical bidirectional transceiver 2 shown in Fig. 4 is capable of single-fiber operation because it has a wavelength division multiplexing (WDM) filter 46 at the optical front end that passes the optical signal from the laser device 44 at one wavelength λ1 and reflects the received optical signal at another wavelength λ2 towards the photodetector 48. The WDM filter 46 inside the opto-electrical bidirectional transceiver 2 is a wavelength selective bandpass filter designed with high crosstalk isolation technology. Using such isolation ensures that the optical signal A from the in situ laser device 44 is not detected by the photodetector 48 in the same bidirectional transceiver, and the optical signal B detected by the photodetector 48 is not received by the laser device 44.

[0034] 4 further includes an optical subassembly 4 mounted on the printed circuit board 40. The optical subassembly 4 has a housing (hereinafter, "OSA housing") consisting of two integrally formed receptacles, including an LC receptacle 75 that receives a terminated optical fiber and a second receptacle that houses an optical component that is optically coupled to the terminated optical fiber.

[0035] 5, the OSA housing 74 includes an LC receptacle 75 having a first cylindrical passageway 96 sized to receive the first end 92 of the termination 28, and an optical component receptacle 73 having a second cylindrical passageway 98 (having a diameter greater than that of the first cylindrical passageway 96). The optical component receptacle 73 of the OSA housing 74 is sized to receive a transmit / receive transistor outline (TO) can 72 that houses the laser device 44, the WDM filter 46, and the photodetector 48. The LC receptacle 75 and the optical component receptacle 73 may be integrally formed or may be rigidly attached to one another.

[0036] The termination 28 further comprises a body 90 and a second end 94. The second end of the termination 28 6. The body 90 and the first end 92 of the termination 28 have a cylindrical cable passage 76 that receives the sheathed portion 86 of the fiber optic cable 20 shown in FIG. 6. The body 90 and the first end 92 of the termination 28 have a common cylindrical fiber passage 78 that receives the unsheathed portion of the optical fiber 88 of the fiber optic cable 20. Thus, if each portion of the fiber optic cable 20 shown in FIG. 6 were inserted into the termination 28 shown in cross section in FIG. 5, the end face of the optical fiber 88 would be aligned and face a lens incorporated in a window (not shown in FIG. 5) formed in the transmit / receive TO can 72. This physical configuration optically couples the laser device 44 and the photodetector 48 (see FIG. 4) to the optical fiber 88 (see FIG. 6). The OSA housing 74 is made of a metallic material (e.g., stainless steel). The termination 28 can be made of a semi-rigid thermoplastic or metallic material (e.g., stainless steel). One commercially available fiber optic cable 20 includes an optical fiber 88 with a polymer core and a fluorinated polymer coating, and a polyethylene sheath 86.

[0037] 7 and 8 are schematic diagrams depicting respective three-dimensional views of a connector system 6 for connecting a fiber optic network to an electrical LRU according to one embodiment. The connector system 6 includes an LRU mating connector 34 and a pluggable active optical connector 32, which are shown in FIGS. 7 and 8 in an aligned but unmated state. FIG. 9A is a schematic diagram depicting a side view of the LRU mating connector 34, and FIG. 9B is a schematic diagram depicting a side view of the pluggable active optical connector 32. As seen in FIGS. 7, 8, 9A, and 9B, the LRU mating connector 34 includes a housing 35, and the pluggable active optical connector 32 includes a connector housing 38. The housings 35 and 38 have a size and shape in accordance with the requirements set forth in the existing aviation standard ARINC 801 (which addresses dimensional, performance, and quality assurance criteria for fiber optic interconnect components suitable for use in commercial aircraft, as well as testing procedures for fiber interconnect assemblies). Each of the housings 35 and 38 has an opening through which an optical fiber can be inserted.

[0038] In addition, the housings 35 and 38 have respective sets of openings for passing various electrical interface components. As best seen in FIG. 7, the LRU mating connector 34 includes a plurality of external electrical wires 64 on the LRU-side of the LRU mating connector 34. The electrical wires 64 are electrically connected to the input / output printed circuit board 8b of the LRU mating connector 34. As best seen in FIG. 8, the LRU mating connector 34 further includes a plurality of electrical pins 62 on the aircraft-side of the LRU mating connector 34. The electrical pins 62 are configured to electrically couple (e.g., plug into) a corresponding plurality of electrical sockets 60 (shown in FIG. 7) incorporated into the pluggable active optical connector 32. The connector housing 38 of the pluggable active optical connector 32 has a plurality of openings on the LRU-side aligned with the electrical sockets 60 and a pair of openings on the aircraft-side through which the respective fiber optic cables 20a and 20b of the fiber optic network can pass. The LRU mating connector 34 and the pluggable active optical connector 32 may be electrically coupled by inserting a plurality of electrical pins 62 into a corresponding plurality of electrical sockets 60 .

[0039] 10A and 11A are schematic diagrams respectively depicting top and side views of the LRU mating connector shown in FIG. 9A without the housing (shown in dashed lines). As seen in FIGS. 10A and 11A, each electrical wire 64 is electrically connected to a corresponding electrical pin 62 by a respective first electrical connector 82, a respective electrical wire 84, and a respective second electrical connector 80. Each first electrical connector 82 connects one end of each electrical wire 84 to a respective electrical wire 64, and each second electrical connector 80 connects the other end of each electrical wire 84 to a respective electrical pin 62. FIG. 12A is a schematic diagram depicting a three-dimensional view of the electrical interface of the LRU mating connector 34 without the housing 35 (shown in dashed lines). The electrical wire 84 connecting the electrical interface is also not shown.

[0040] 10B, 11B, and 12B are schematic diagrams respectively illustrating a top view, a side view, and a three-dimensional view of the assembled internal components of the pluggable active optical connector 32 shown in FIG. 9B, excluding the connector housing (shown in dashed lines). The internal components of the pluggable active optical connector 32 include a pair of printed circuit boards 68 and 70 that electrically communicate with the LRU via the electrical socket 60. The internal components of the pluggable active optical connector 32 further include a first OSA housing 74a mounted on the printed circuit board 68 and a second OSA housing 74b mounted on the printed circuit board 70. Each of the first and second LC receptacles 74a and 74b can have the same structure as the OSA housing 74 shown in FIG. 5. Further, the internal components of the pluggable active optical connector 32 include a first termination 28a for terminating the first optical fiber cable 20a and a second termination 28b for terminating the second optical fiber cable 20b. Each of the first and second terminations 28a and 28b may have the same structure as the termination 28 shown in FIG. 5. When the end of the termination 28a is inserted into the OSA housing 74a, the optical fiber cable 20a optically couples to the optical components inside the transmit / receive TO can 72 (see FIG. 5) housed in the OSA housing 74a. Similarly, when the end of the termination 28b is inserted into the OSA housing 74b, the optical fiber cable 20b optically couples to the optical components inside the transmit / receive TO can 72 (see FIG. 5) housed in the OSA housing 74b. The optical components of the bidirectional transceiver inside each TO can 72 include the laser device 44, the photodetector 48, and the WDM filter 46 as shown in FIG. 4. FIG. 13 shows a side view of the assembled internal components of the pluggable active optical connector 32 shown in FIG. 12B, while FIGS. 14 and 15 show three-dimensional views, respectively, of the assembled internal components of the pluggable active optical connector 32 shown in FIG. 12B.

[0041] 16 is a flow chart identifying steps of a method 150 for assembling an avionics data transmission system according to one proposed embodiment. Method 150 performs the recited steps in the order indicated by the arrows. However, in alternative embodiments, the steps may be performed according to a different order. The following description in the next paragraphs describes the steps of method 150 in the order indicated by the arrows in FIG. 16. However, alternative sequences of the various steps may be described as appropriate.

[0042] Referring to FIG. 16, the first plurality of electrical connectors are connected to the circuit on the printed circuit board (step 152). After step 152, the laser device and the photodetector of the optical-electrical bidirectional transceiver are connected to the circuit on the printed circuit board (step 154) (alternatively, step 154 ​​may be performed before step 152). After step 154, the end of the optical fiber cable of the onboard optical fiber network of the aircraft is terminated at the termination (step 156) (alternatively, step 156 may be performed before step 154). After step 156, the termination is inserted into the receptacle mounted on the printed circuit board until the end face of the optical fiber cable is located within a specified distance from the optical-electrical bidirectional transceiver and facing the optical-electrical bidirectional transceiver (step 158). After step 158, the first plurality of electrical connectors are aligned with the second plurality of electrical connectors of the mating connector mounted on the onboard line replaceable unit of the aircraft (step 160). After step 160, the printed circuit board is moved toward the line replaceable unit (step 162) while maintaining alignment of the first and second plurality of electrical connectors, thereby connecting the first plurality of electrical connectors to the second plurality of electrical connectors (alternatively, steps 160 and 162 may be performed before step 158).

[0043] The pluggable active optical connector 32 can be plugged directly into an LRU having an electrical interface that conforms to the electrical pinout definition of the pluggable active optical connector 32. To accommodate an LRU with a different electrical connector and pinout definition (e.g., electrical pins from two connectors are required), the pluggable active optical connector 32 can be mounted on a rail near the LRU and a short electrical wiring harness can be adapted to the different connector.

[0044] Figure 17 is a schematic diagram of an electrical LRU 10b capable of receiving data from and transmitting data to optical avionics data bus fiber optic cables 20a and 20b when two LRU-side connectors 34a and 34b are electrically coupled to aircraft-side pluggable active optical connector 32 using a short jumper cable 66 in accordance with an alternative embodiment. Connectors 34a, 34b, and 32 and jumper cable 66 are shown unmated in Figure 17. Jumper cable 66 is an electrical cable having a generic (non-compliant) connector (not shown, as it can be any type that mates with an existing type of LRU connector) on one end and a specific connector that mates with pluggable active optical connector 32 on the other end.

[0045] An alternative that results in a shorter and simpler module is to replace the pluggable optical contacts with a short length of optical pigtail (the fiber is permanently affixed to the OSA with epoxy). The drawback of the pigtail alternative is that failure of the pigtail fiber itself can lead to the scrapping of the entire module.

[0046] FIGURE 18 is a schematic diagram of an electrical LRU 10b capable of receiving data from and transmitting data to the optical avionics data bus fiber optic cables 20a and 20b when mated with the aircraft pluggable active optical connector 32 with pigtails 58a and 58b secured thereto by epoxy in accordance with a further alternative embodiment. The connectors are shown unmated in FIGURE 18. The pigtails are fiber optic cables permanently aligned and attached (by epoxy) to the OSA 4 (not shown in FIGURE 18, but see FIGURE 4) without the need for a receptacle connector (no need to plug and unplug, therefore no terminations in the OSA connection). There is a termination (not shown) at the other end of the pigtail for an in-line connection on the aircraft.

[0047] Although the pluggable active optical connector has been described with reference to various embodiments, those skilled in the art will recognize that various changes and equivalent substitutions may be made to the elements thereof without departing from the teachings herein. Moreover, many modifications may be made to adapt the concepts and implementations disclosed herein to a particular situation. Accordingly, the subject matter protected by the claims is not limited to the disclosed embodiments.

[0048] The method claims set forth below should not be construed as requiring that the steps be performed in alphabetical order (wherein alphabetical ordering in the claims is used merely to refer to previously described steps) or in the order in which they are described, unless the claim language expressly specifies or declares a condition indicating a particular order of performance of some or all of the steps described therein. The method claims should not be understood to exclude the simultaneous or alternating performance of any portion of two or more steps, unless the claim language expressly declares a condition that prevents such an interpretation.

[0049] Note: The following notes describe further aspects of the present disclosure.

[0050] A1. A method for assembling a data transmission system, comprising: (a) connecting a first plurality of electrical connectors to circuits on a printed circuit board; (b) connecting a laser device and a photodetector of an optical subassembly of an optical-to-electrical bidirectional transceiver to the circuitry on the printed circuit board; (c) positioning an end of a fiber optic cable of an aircraft's onboard fiber optic network facing the optical subassembly of the optical-electrical bidirectional transceiver; (d) connecting the first plurality of electrical connectors to a second plurality of electrical connectors of a mating connector mounted to an on-board line replaceable unit of the aircraft; The method includes:

[0051] A2. The method of claim A1, wherein step (d) includes inserting the second plurality of electrical connectors into the first plurality of electrical connectors, respectively.

[0052] A3. Step (d) is aligning the first plurality of electrical connectors with the second plurality of electrical connectors; moving the printed circuit board toward the line replaceable unit while maintaining alignment of the first and second pluralities of electrical connectors; The method according to claim A1 or A2, comprising:

[0053] A4. The method of any of claims A1-A3, wherein the printed circuit board is moved toward the line replaceable unit until one of the first and second pluralities of electrical connectors is fully inserted into the other of the first and second pluralities of electrical connectors.

[0054] A5. Step (c) is terminating the end of the fiber optic cable at a termination; inserting the termination into a receptacle mounted on the printed circuit board until an end face of the fiber optic cable faces a window of the optical subassembly of the optical-electrical bidirectional transceiver within a specified distance; The method according to any one of Appendices A1 to A4, comprising:

Claims

1. A connector housing; a first printed circuit board accommodated within the connector housing; a first plurality of electrical connectors electrically coupled to and supported by the first printed circuit board; a first bidirectional optical subassembly comprising a first laser device and a first photodetector electrically coupled to the first printed circuit board; a first housing attached to the first printed circuit board and including a first receptacle configured to accommodate the first bidirectional optical subassembly and a second receptacle configured to receive one end of a first termination portion that terminates a first optical cable; the first laser device is electrically coupled to a first pair of electrical connectors of the first plurality of electrical connectors and is positioned to transmit light through the first housing to an end of a first optical fiber in response to an electrical signal received via the first pair of electrical connectors of the first plurality of electrical connectors; a first photodetector electrically coupled to a second pair of electrical connectors of the first plurality of electrical connectors and configured to transmit an electrical signal to the second pair of electrical connectors of the first plurality of electrical connectors in response to receiving light from the end of the first optical fiber;

2. The pluggable active optical connector of claim 1 , wherein said first plurality of electrical connectors are electrical sockets.

3. 3. The pluggable active optical connector of claim 1, wherein the first bidirectional optical subassembly further comprises a wavelength division multiplexing filter optically coupled to the first laser device and the first photodetector.

4. a second printed circuit board accommodated within the connector housing; a second plurality of electrical connectors electrically coupled to and supported by the second printed circuit board; a second bidirectional optical subassembly comprising a second laser device and a second photodetector electrically coupled to the second printed circuit board; a second housing attached to the second printed circuit board and including a first receptacle configured to accommodate the second bidirectional optical subassembly and a second receptacle configured to receive one end of a second termination portion that terminates a second optical cable; the second laser device is electrically coupled to a first pair of electrical connectors of the second plurality of electrical connectors and is positioned to transmit light through the second housing to an end of a second optical fiber in response to electrical signals received via the first pair of electrical connectors of the second plurality of electrical connectors; The pluggable active optical connector of any one of claims 1 to 3, wherein the second photodetector is electrically coupled to a second pair of electrical connectors of the second plurality of electrical connectors and is arranged to transmit an electrical signal to the second pair of electrical connectors of the second plurality of electrical connectors in response to receiving light from the end of the second optical fiber.

5. The first bidirectional optical subassembly includes: a first wavelength division multiplexing filter optically coupled to the first laser device and a first photodetector; a second wavelength division multiplexing filter optically coupled to the second laser device and the second photodetector; 5. The pluggable active optical connector of claim 4, further comprising:

6. 6. The pluggable active optical connector of claim 4, further comprising a rubber seal disposed inside the connector housing, the rubber seal configured to surround a portion of each of the first and second optical fibers when the first and second end portions are inserted into the first and second housings, respectively.

7. An optical fiber network; A plurality of electronic devices; a plurality of mating connectors respectively mounted to and electrically coupled to the plurality of electronic devices, each connector having a plurality of electrical connectors; a plurality of pluggable active optical connectors respectively mounted on and electrically coupled to the plurality of mating connectors and optically coupled to the optical fiber network; Equipped with A data transmission system, wherein each of the plurality of pluggable active optical connectors comprises a respective first optical-electrical bidirectional transceiver and a plurality of electrical connectors respectively electrically coupled to the electrical connector of a respective mating connector.

8. 8. The data transmission system of claim 7, wherein each of said plurality of pluggable active optical connectors further comprises a respective second optical-electrical bi-directional transceiver.

9. 9. The data transmission system of claim 8, wherein the optical fiber network comprises a plurality of optical fiber cables, and the first and second optical-electrical bidirectional transceivers of each pluggable active optical connector are optically coupled to a respective one of the plurality of optical fiber cables.

10. The data transmission system according to any one of claims 7 to 9, wherein the electronic device is a line replaceable unit.

11. The data transmission system of claim 10 , wherein the line replaceable unit is installed in an aircraft.

12. The data transmission system according to any one of claims 7 to 11, wherein the first optical-electrical bidirectional transceiver comprises a laser device and a photodetector.

13. 13. The data transmission system of claim 12, wherein the first optical-electrical bidirectional transceiver further comprises a wavelength division multiplexing filter optically coupled to the laser device and the photodetector.

14. The first optical-electrical bidirectional transceiver includes: a pair of data input terminals electrically coupled to respective electrical connectors of one of the mating connectors; a laser driver electrically coupled to said pair of data input terminals and to said laser device; The data transmission system of claim 13 further comprising:

15. The first optical-electrical bidirectional transceiver includes: a pair of data output connectors electrically coupled to respective electrical connectors of said one mating connector; A power terminal, a transimpedance amplifier electrically coupled to the pair of data output terminals and to the photodetector; The data transmission system of claim 14 further comprising:

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