CN1529955A - High Speed Optical Data Link - Google Patents

Abstract

A high speed optical data link comprising: a system circuit board (200), a first ASIC (212) for communicating electrical information to and from the superior data management circuit, and a second ASIC (252) electrically coupled to the first ASIC. A fiber optic module mounted on the system circuit board contains a receiver, a transmitter, and a second ASIC. The receiver includes a photodiode (216) for receiving the optical signal, a transimpedance amplifier electrically coupled to the photodiode, and a post-amplifier electrically coupled to the transimpedance amplifier and the second ASIC. The transmitter includes a laser (220) for transmitting the optical signal to the remote optical receiver and a laser driver (218) electrically coupled to the laser and the second ASIC. Both the first and second ASICs include clock synchronization and equalization/retiming functions to recover distorted data transmitted therebetween via electrical lines on the system circuit board so that electrical data is transmitted at or above 10-20 Gbps.

Description

High Speed Optical Data Link

technical field

The present invention relates to optical transmitters, receivers and transceivers.

More specifically, the present invention relates to data links in optical transmitters, receivers and transceivers.

Background technique

Optical transmitters, receivers, and transceivers are used to convert electrical data to optical data for transmission over optical fibers and to convert optical data back to electrical data for processing by network equipment. Typically, an optical transmitter includes a light source, such as a laser driver and a laser diode, and an optical receiver includes optical conversion devices, such as a post-amplifier, a transimpedance amplifier, and a PIN photodiode or APD. The transmitter or receiver is usually mounted on a network circuit board, together with other data processing IC chips such as parallel-serial converters or deserializers, data framers for encoding such as 8B/10B encoding, and advanced data control ICs interface connection. However, when data transmission rates reach about 10Gbps or higher, this type of structure cannot be used because the electrical traces on the printed circuit board introduce noise and chatter and distort signal integrity at such high frequencies .

Current technology requires the integration of parallel-to-serial converters and deserializers on the transmitter and receiver modules to enable the electrical interface to operate at low frequencies. As an example, for the OC192 data rate, the electrical interface of the data link module requires 16 channels of 622 Mbps. Then, a module called a fiber optic transponder is installed on this circuit board to interface with other IC chips to realize network management functions. Therefore, the module requires many electrical interfaces with typically more than 50 pins. The large number of pins and additional internal circuitry necessitates a large module size. Power consumption is also a serious issue.

Accordingly, it would be highly beneficial to eliminate the above and other deficiencies inherent in the prior art.

It is therefore an object of the present invention to provide a new and improved high speed optical data link.

Another object of the present invention is to provide a new and improved high speed optical data link capable of transmitting data at rates of about 10 Gbps or higher.

Another object of the present invention is to provide a new and improved high speed optical data link which is simple and relatively inexpensive to manufacture.

It is another object of the present invention to provide a new and improved high speed optical data link which is smaller in size than prior art devices and has a lower number of electrical pins capable of transferring information at the same rate.

Contents of the invention

Briefly, to achieve the desired objectives of the present invention consistent with the preferred embodiments, there is provided a high speed optical data link comprising a system board having first and second ASICs mounted thereon. The first ASIC contains clocking and equalization functions for recovering distorted data. The second ASIC is electrically coupled to the first ASIC for communicating electrical signals therebetween, and the second ASIC includes one of clock synchronization and equalization functions for recovering the distorted data.

In a more specific embodiment, the high speed optical data link includes a first ASIC for communicating electrical information to a remote circuit and a second ASIC electrically coupled to the first ASIC and for communicating electrical signals therebetween. A fiber optic receiver module is mounted on a system circuit board and includes: a photodiode for receiving an optical signal from a remote source, a transimpedance amplifier electrically coupled to the photodiode, and a sensor such as Limiting amplifier or post-amplifier for self-gain control circuits. The second ASIC includes clock synchronization and equalization functionality for data integrity and the first ASIC includes functionality for recovering distorted data using the same clock synchronization and equalization scheme provided by the second ASIC.

In another more specific embodiment, the high speed optical data link further comprises: a first ASIC for receiving electrical information from the remote circuit and a first ASIC electrically coupled to the first ASIC and for transmitting electrical signals therebetween. Two ASICs. A fiber optic receiver module mounted on a system circuit board includes a laser for transmitting an optical signal to a remote source and a laser driver electrically coupled to the laser and a second ASIC. A first ASIC contains clock synchronization and may contain equalization functions for data transmission, and a second ASIC contains equalization functions for recovering distorted data with the same clock synchronization. It should be noted that alternatively, the last two described embodiments could both be packaged and contained on a common motherboard with common first and second ASICs.

The embodiments described above include an innovative method of electrically transferring information on a circuit board at a rate of 10 gigabits per second or higher. The method comprises the steps of: providing a system circuit board comprising a first location and a second location, receiving an electrical signal from an external source at the first location of the system circuit board, clock synchronizing and equalizing the electrical signal on the system circuit board, To provide a signal with integrity, transmit the equalized signal to a second location on the system circuit board, and receive the equalized signal at the second location and use de-colcking and re-timing ) steps to restore the distorted signal.

Description of drawings

With reference to the accompanying drawings, the following detailed description of preferred embodiments will make the above and further and more specific objects and advantages of the present invention more apparent to those skilled in the art. In the attached picture:

Figure 1 is a simplified block diagram/top plan view of a prior art optical data link; and

Figure 2 is a simplified high speed optical data link in accordance with the present invention.

Detailed ways

Referring to FIG. 1 , a simplified block diagram/top plan view of a prior art optical data link 100 is shown. The data link 100 includes a system board 101 on which the fiber optic transponder 0 is mounted. Electrical connections to the various elements of the transponder 110 are not shown since they are provided within the mounting structure by interconnections in a conventional manner. Repeater 110 includes deserializer/deserializer 112 electrically connected to transimpedance amplifier and postamplifier 114 , which is electrically connected to PIN photodiode 116 . Photodiode 116 is used to receive a modulated light signal from the optical fiber indicated by arrow 140 . The serializer/deserializer 112 is also electrically connected to a laser driver 118 for driving a laser diode 120 . A laser diode 120 is placed for supplying the modulated output light to an optical fiber indicated by arrow 130 . The input and output electrical signals for the transponder 110 are supplied from a board level IC chip, generally indicated at 150, by an electrical interface, indicated at 160, comprising connectors and printed circuit board copper traces.

The connectors and lines of the electrical interface 160 on the printed circuit board 101 introduce noise and chatter, which makes the high frequency (for example, 10 gigabits per second or more) transmitted between the repeater 110 and the on-board IC chip 150 ) Signal integrity distortion of the signal. Because of this distortion, the electrical interface 160 must operate at low frequencies, which requires a large number of channels. For example, a 10Gbps signal is converted by the deserializer/deserializer 112 into 16 channels of 622Mbps differential signals. However, the use of serializer/deserializer 112 and 16 channels in transponder 110 greatly increases the number of pins or connections within electrical interface 160 . The 16 channels and associated connections greatly increase the size and power requirements of repeater 110 .

Turning now to FIG. 2, a simplified high speed optical data link 200 in accordance with the present invention is shown. Data link 200 includes system board 201 on which fiber optic transceiver 210 is mounted. Electrical connections to the various elements of transceiver 210 are not shown as they are provided within the mounting structure by interconnections in a conventional manner. The transceiver 210 includes a first ASIC 212 electrically connected to an optical conversion device, shown herein for exemplary purposes as a transimpedance/post-amplifier 214 electrically connected to a PIN photodiode 216. A photodiode 216 is positioned to receive a modulated light signal from the optical fiber indicated by arrow 240 . The ASIC 212 is also electrically connected to a light generating device, which is shown herein for exemplary purposes as a laser driver 218 for driving a laser diode 220. A laser diode 220 is placed for supplying the modulated output light to an optical fiber indicated by arrow 230 .

Input and output electrical signals for transceiver 210 are supplied by an electrical interface indicated at 260 comprising connectors and printed circuit board copper traces and the like. A board-level IC chip, generally indicated at 250, includes a second ASIC 252 connected by an electrical interface 260 to a first ASIC 212 in the transceiver 210. Although a transceiver incorporating both an optical transmitter and an optical receiver is shown in this example for purposes of illustration, it should be understood that the pair of ASICs could be used in a single optical transmitter, a single optical receiver, an optical transceiver, or on any combination of .

By combining this pair of ASICs in an optical transmitter, receiver or transceiver, a standard electrical interface 260 can be used to directly establish a 10Gbps or higher serial electrical interface between the transceiver 210 and the system board 250, for example Pin grid arrays, ball grid arrays, edge connectors, etc. Clock data recovery (CDR) is built into each ASIC 212 and 252. Likewise, each ASIC 212 and 252 is used to receive electrical signals from interface 260 and to send electrical signals through interface 260. ASIC 212 or ASIC 252 retimes and clocks this signal and provides drive power for the transmit section. For the receive portion of the ASICs 212 and 252, they simultaneously process and recover distorted data caused by sending high-frequency signals directly over the board's wires.

Clock synchronization and equalization/retiming can be performed using various techniques, one of which is described in detail in a paper by Abhijit Phanse, submitted to IEEE, New Orleans, September 2000, a copy of which is attached at are incorporated by reference in this document.

Accordingly, each fiber optic data link contains a fiber optic transmitter module with: a first ASIC for equalizing/retiming and recovering electrical signals distorted on the electrical lines of the system board; The second ASIC inside is used for clock synchronization and equalization of electrical data and provides the drive power sent to the optical transmitter module via the electrical lines on the printed circuit board. The described fiber optic data link system operates at data rates higher than 5Gbps. In a preferred embodiment, the second ASIC on the system board contains clock synchronization and equalization functions for data transmission on the printed circuit lines and the first ASIC in the transmitter module contains functions for utilizing the same clock provided by the second ASIC. The encoding and clock synchronization scheme to recover the function of distorted data. In another embodiment, a second ASIC on the system board contains a parallel-to-serial converter for data serial, clock synchronization and equalization functions and drive power for data transmission on printed circuit lines, and the transmitter The first ASIC within the module contains functionality for recovering distorted data using the same clock synchronization scheme provided by the second ASIC.

As a typical example, a fiber optic data link consists of a fiber optic receiver module mounted on a system printed circuit board. The fiber optic receiver module contains photodiodes, transimpedance amplifiers, postamplifiers and a first ASIC for clock synchronization and equalization of electrical data and providing drive power sent to the system printed circuit board via electrical traces on the printed circuit board. The system printed circuit board contains a connected second ASIC designed to recover electrical signals distorted on the electrical lines of the system printed circuit board. In this embodiment, a first ASIC on the receiver module contains clock synchronization and retiming functions for data transmission and provides electrical signal drive power and a second ASIC on the system board contains The same clock synchronization scheme is used to recover the function of the distorted data. Also in this embodiment, a first ASIC on the receiver module contains clock synchronization and equalization functions for data transmission, and a second ASIC on the system board contains functions for utilizing the same clock provided by said first ASIC. A synchronization scheme to recover the function of distorted data and may further include a deserializer for data deserialization.

In another example, a fiber optic data link system includes a fiber optic transceiver module mounted on a system printed circuit board, the fiber optic transceiver module including a transmitter including a laser diode and a laser driver, a receiver, and a first ASIC.

The receiver contains a photodiode, a transimpedance amplifier, and a postamplifier. The first ASIC performs clock synchronization and equalization/retiming functions on the data from the receiver and provides drive power sent to the system board via electrical lines on the printed circuit board. The first ASIC also performs recovery functions on distorted electrical data from the system board via electrical lines on the printed circuit board for transmission to the transmitter. The system printed circuit board contains a second ASIC for recovering the electrical data from the optical transceiver distorted on the electrical lines on the system printed circuit board, as well as clock synchronizing and equalizing the electrical data and providing it on the printed circuit board for sending to The driving power of the optical transceiver module.

The first ASIC on the transceiver module also contains clock synchronization and equalization/retiming functions for data transmission on the receiver side to recover from distortion using the same clock synchronization scheme provided by the second ASIC on the system board data function, and the second ASIC on the system board contains the same clock synchronization scheme provided by the first ASIC to recover the distorted data function and the clock synchronization used to send the data to the transceiver via the electrical lines on the board Function. The first ASIC on the transceiver module also contains clock synchronization functions for data equalization on the receiver side and encoding functions to recover distorted data using the same encoding scheme provided by the second ASIC on the system board .

A second ASIC on the system board contains functions for recovering distorted data using the same retiming and clock synchronization scheme provided by the first ASIC, clock synchronization and equalization for sending data to the transceiver via the electrical lines on the board function, a parallel-serial converter function for data serialization and a deserializer for data deserialization.

Accordingly, the present invention discloses a new and improved high speed optical data link comprising a pair of ASICs providing clock synchronization and equalization functions for sending data through a system board at 10 Gbps or higher. In this way, fiber optic modules such as transmitters, receivers or transceivers have a smaller size, lower power consumption and a lower electrical pin count. At the same time, the transceiver can be inserted more easily.

Various changes and modifications may be made to the embodiments for illustrative purposes by those skilled in the art. Such modifications and changes do not depart from the spirit of the present invention, they are included in the scope of the present invention, and they can only be judged by a proper understanding of the appended claims.

The present invention has been clearly and concisely described to enable those skilled in the art to understand and practice the invention.

Claims (22)

1. A high-speed optical data link comprising: system circuit board; a first ASIC mounted on the system circuit board, the first ASIC including clock synchronization and equalization/retiming functionality for transmitting data and recovering one of the distorted data; and A second ASIC mounted on the system circuit board and electrically coupled to the first ASIC for transmitting electrical signals therebetween, the second ASIC containing clock synchronization and equalization/retiming for sending data and recovering one of the distorted data Function. 2. The high-speed optical data link of claim 1, further comprising: an optical receiver with a photodiode, a transimpedance amplifier, and a post-amplifier electrically coupled to the first ASIC and the second ASIC. one. 3. The high-speed optical data link of claim 2, further comprising: an input terminal for receiving optical information from an external light source coupled to the photodiode and for providing an output electrical signal based on the received optical information and coupled to to the output terminal of the post amplifier. 4. The high speed optical data link of claim 1, further comprising: an optical transmitter with a laser diode and a laser driver, the laser driver being electrically coupled to one of the first ASIC and the second ASIC. 5. The high-speed optical data link of claim 4, further comprising: an input terminal for receiving input electrical information and coupled to the laser driver and for providing an output optical signal to an external optical receiver based on the received electrical information and coupled to the output terminal of the laser. 6. The high speed optical data link of claim 1, further comprising: a board level IC chip electrically coupled to one of the first ASIC and the second ASIC. 7. A high-speed optical data link comprising: system circuit board; a first ASIC for communicating electrical information to remote circuitry and a second ASIC electrically coupled together for communicating electrical signals therebetween via electrical lines on the system circuit board; and A fiber optic receiver module mounted on a system circuit board, the receiver module contains a photodiode for receiving an optical signal from a remote source, a transimpedance amplifier electrically coupled to the photodiode, and a postamplifier electrically coupled to the transimpedance amplifier and said second ASIC coupled to the postamplifier, the second ASIC includes clock synchronization and equalization/retiming functions for data transmission, the first ASIC on the system circuit board includes functions for utilizing the The same clock synchronization function to restore the function of distorted data. 8. The high speed optical data link of claim 7, wherein the remote circuitry comprises at least one board level IC chip electrically coupled to the first ASIC. 9. The high speed optical data link of claim 7, wherein said remote source of optical signals comprises an optical fiber. 10. A high-speed optical data link comprising: system circuit board; a first ASIC for receiving electrical information from the remote circuit and a second ASIC electrically coupled to the first ASIC and for transmitting electrical signals therebetween via electrical lines on the system circuit board; and An optical fiber transmitter module installed on a system circuit board, the transmitter module includes a laser for transmitting an optical signal to a remote optical receiver, a laser driver electrically coupled to the laser, and said second ASIC electrically coupled to the laser driver, the system The first ASIC on the circuit board contains clock synchronization and equalization/retiming functions for data transmission, and the second ASIC contains functions for recovering distorted data using the same clock synchronization functions provided by the first ASIC. 11. The high speed optical data link of claim 10, wherein the remote circuitry comprises at least one board level IC chip electrically coupled to the first ASIC. 12. The high speed optical data link of claim 10, wherein said remote optical receiver to which said optical signal is transmitted comprises an optical fiber. 13. A high-speed optical data link comprising: system circuit board; A first ASIC mounted on a system circuit board for transmitting electrical information to and receiving electrical information from a remote circuit, and a second ASIC mounted in an optical module and electrically coupled to the first ASIC for transmitting electrical information via the system The wires on the circuit board carry electrical signals between them; A fiber optic receiver mounted in an optical module, the receiver includes a photodiode for receiving an optical signal from a remote source, a transimpedance amplifier electrically coupled to the photodiode, and a post-amplifier electrically coupled to the transimpedance amplifier and a second ASIC an amplifier, the second ASIC includes clock synchronization functionality and equalization/retiming functionality for data transmission, the first ASIC includes functionality for recovering distorted data utilizing the same clock synchronization functionality provided by the second ASIC; and A fiber optic transmitter installed in an optical module, the transmitter includes a laser for transmitting optical signals to a remote optical receiver and a laser driver electrically coupled to the laser and a second ASIC, the first ASIC includes a clock synchronization function for data transmission and equalization functions, and the second ASIC includes functions for recovering distorted data using the same clock synchronization function provided by the first ASIC. 14. A high-speed optical data link comprising: System circuit board with electrical wiring; The IC installed on the system circuit board is used to transmit the electrical information from the upper-level data management circuit to the optical transceiver module and receive the electrical information from the optical transceiver module and transmit it to the upper-level data management circuit. an ASIC in the transceiver module and electrically coupled to the IC on the system circuit board via electrical lines on the system circuit board for transmitting electrical signals therebetween; A fiber optic receiver installed in an optical transceiver module, the receiver includes a photodiode for receiving an optical signal from a remote light source, a transimpedance amplifier electrically coupled to the photodiode, and a transimpedance amplifier electrically coupled to the transimpedance amplifier and the optical transceiver module A post-amplifier for an ASIC that includes one of a clock synchronization function and an equalization/retiming function for data transmission; and An optical fiber transmitter installed in an optical transceiver module, the transmitter includes a laser for transmitting optical signals to an external optical receiver and a laser driver electrically coupled to the laser and the ASIC in the optical transceiver module, the ASIC in the optical transceiver module Contains an equalization/retiming function to recover distorted data for data transmission through the laser. 15. A method of electrically communicating information on a circuit board at a rate equal to or greater than 10 gigabits per second, comprising the steps of: providing a system circuit board comprising a first location and a second location; receiving an electrical signal from an external source at a first location on a system circuit board; Clock synchronization and equalization/retiming of electrical signals on system boards for data transmission; delivering the equalized signal to a second location on the system circuit board; and The equalized signal is received at a second location and the distorted signal is recovered using clock recovery and equalization/retiming steps. 16. A method of electrically communicating information on a circuit board at a rate at least equal to 10 gigabits per second, comprising the steps of: Provides system boards containing optical transmitter modules with laser diodes and laser drivers; receiving an electrical signal from an external source at a first location on a system circuit board; Clock synchronization and equalization/retiming of electrical signals on system boards for data transmission; sending the equalized signal to a second location on the system circuit board via an electrical line; receiving the signal at the second location and recovering the distorted signal using clock recovery and equalization/retiming steps; and Send the recovered equalized signal to the laser driver. 17. The method of claim 16, wherein said step of receiving an electrical signal from an external source comprises providing at least one board-level IC chip electrically coupled to the first ASIC to supply the electrical signal. 18. The method of claim 16, further comprising the step of providing an optical fiber optically coupled to the laser to receive an optical signal from the laser. 19. A method of electrically communicating information on a circuit board at a rate at least equal to 10 gigabits per second, comprising the steps of: System boards containing optical receiver modules with photodiodes, transimpedance amplifiers, and postamplifiers are available; Receive an optical signal from an external source with a photodiode, convert the optical signal into an electrical signal in a transimpedance amplifier and amplify the electrical signal to provide an amplified electrical signal at the output of the post-amplifier; clocking and equalizing/retiming the amplified electrical signal at a first location on the system circuit board to provide a balanced signal; Sending the equalized signal to a second location on the system circuit board; receiving the signal at the second location and recovering the distorted signal using clock recovery and equalization/retiming steps; and The recovered electrical signal is transmitted from the second location to an external source. 20. The method of claim 19, wherein said step of transmitting the recovered electrical signal from the second location to an external source comprises: providing at least one board-level IC chip electrically coupled to the first ASIC to receive Recovered electrical signal. 21. The method of claim 19, wherein said step of receiving an optical signal from an external source includes optionally optically coupling a fiber optic to a photodiode to receive an optical signal from the photodiode. 22. A method of electrically communicating information on a circuit board at a rate at least equal to 10 gigabits per second, comprising the steps of: Provides system boards containing optical transceiver modules with photodiodes, transimpedance amplifiers, postamplifiers, laser diode drivers, laser diodes, and ASICs; receiving an optical signal from an external source with a photodiode, converting the optical signal into a first electrical signal and amplifying the first electrical signal in a transimpedance amplifier to provide the amplified first electrical signal at the output of the post-amplifier; clock synchronizing and equalizing/retiming the amplified first electrical signal in the optical transceiver module on the system circuit board to provide an equalized first signal in the first location on the system circuit board; transmitting the equalized first signal from the first location to a second location on the system circuit board; receiving the equalized first signal at a second location, clocking the equalized first signal to provide a restored first electrical signal, and transmitting the restored first electrical signal from the second location to a superior data management circuit; receiving a second electrical signal from a superior data management circuit, clock synchronizing and equalizing/retiming the second electrical signal to provide an equalized second signal at a second location on the system circuit board; transmitting the equalized second signal to the optical transceiver via the first location on the system circuit board and via electrical lines on the system circuit board; and clock recovering the equalized second signal in the first location using an ASIC in the optical transceiver, sending the recovered second signal to a laser driver, and generating an optical signal on a laser diode modulated according to the recovered second signal, to send optical signals to remote external optical receivers.