Patent Application
20050259994
This disclosure relates to electro-optical devices, specifically, optical transceiver modules for telecommunication and data communication applications.
Computers are increasingly being connected to communication lines and other devices or networks with the computers performing as servers to the peripherally connected computers or devices. The volume of data sent and received by the computer serving as a server of a network is such that the networks are advantageously constructed using fiber optic lines in order to increase the throughput of data.
Fiber optic lines and the associated fiber optic signals require transceivers to convert the optical light pulse signals to electronic signals which are usable by the computer. Such a transceiver includes a transmitter optical component and a receiver optical component to send and receive the optical signals. Modem optical transceivers have been modularized with standard physical sizes, under standard electrical interface agreements and standard optical interface agreements. One of such standard agreements is the Small Form-factor Pluggable Multi-Source Agreement (SFP MSA).
A Printed Circuit Board (PCB) is a major component of an optical transceiver module. All transmission and reception circuits are built on this Printed Circuit Board. In the modem telecommunication and data communication applications, the dimension of an optical transceiver module is getting smaller and the optical transceiver module is required to support more functions. However, the limited usable area of a PCB makes function extension difficult. It is therefore desirable for a Printed Circuit Board to hold more functions for a fixed working space. Additionally, it is also desirable to reduce electromagnetic interference between different parts of a Printed Circuit Board.
In one aspect, optical transceiver module is disclosed, comprising
a housing comprising a first end and a second end;
an electrical interface associated with the first end, said electrical interface being adapted to be locked into a socket of a receiving cage;
an optical interface associated with the second end, said optical interface adapted to be connected with one or more optical transceiver components;
a first Printed Circuit Board having a first function circuit connected with the electrical interface; and
a second Printed Circuit Board having a second function circuit that is electrically connected with the first function circuit,
wherein the second Printed Circuit Board is disposed substantially perpendicular to the first Printed Circuit Board.
In another aspect, an optical transceiver module is disclosed, comprising
a housing comprising a first end and a second end;
an electrical interface associated with the first end, said electrical interface being adapted to be locked into a socket of a receiving cage;
an optical interface associated with the second end, said optical interface adapted to be connected with one or more optical transceiver components; and
a Printed Circuit Board (PCB) module, comprising a first Printer Circuit Board having a first function circuit; and a plurality of second Printed Circuit Boards each comprising a second function circuit that are electrically connected to the first function circuit.
In yet another aspect, an optical transceiver module is disclosed, comprising a housing comprising a first end and a second end;
an electrical interface associated with the first end, said electrical interface being adapted to be locked into a socket of a receiving cage;
an optical interface associated with the second end, said optical interface adapted to be connected with one or more optical transceiver components;
a first Printed Circuit Board having a first function circuit connected with the electrical interface; and
a multi-layer second Printed Circuit Board comprising a second function circuit in the multi-layer structure, wherein the second Printed Circuit Board is electrically connected with the first function circuit.
Embodiments may include one or more of the following advantages. The PCB area is increased using a second PCB in addition to the first PCB. The two PCBs fit the same modular physical dimensions. This solution provides an optical transceiver module manufacturer the freedom of increase the functions of its optical transceiver module without developing new IC designs, which can reduce development time and be very cost effective.
The disclosed system also include one or more of the following advantages. The second Printed Circuit Board can divide the first Printed Circuit Board into two circuit areas. The transmission circuits are laid out in one circuit area while the reception circuits in another. The second Printed Circuit Board can provide electromagnetic shielding and thus minimize electromagnetic interference between the transmission path and the reception path.
The system disclosed increases functionality of the optical transceiver module while still being compatible with industry standards. The disclosed optical transceiver module is robust and reliable.
Reference will now be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with the preferred embodiments, it will be understood that they are not intended to limit the invention to these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as defined by the appended claims. Furthermore, in the following detailed description of the present invention, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be obvious to one of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well known methods, procedures, components, and circuits have not been described in detail as not to unnecessarily obscure aspects of the present invention.
Computers are increasingly being connected to communication lines and other devices or networks with the computers performing as servers to the peripherally connected computers or devices. The volume of data sent and received by the computer serving as a server of a network is such that the networks are advantageously constructed using fiber optic lines in order to increase the throughput of data.
Fiber optic lines and the associated fiber optic signals require transceivers to convert the optical light pulse signals to electronic signals which are usable by the computer. Such a transceiver includes a transmitter optical component and a receiver optical component to send and receive the optical signals. Modern optical transceivers have been modularized with standard physical sizes, under standard electrical interface agreements and standard optical interface agreements. One of such standard agreements is the Small Form-factor Pluggable Multi-Source Agreement (SFP MSA).
A Printed Circuit Board (PCB) is a major component of an optical transceiver module inside the module's case body. Transmission and reception circuits are commonly built on this Printed Circuit Board. In modern telecommunication and data communication applications, the dimensions of optical transceiver modules continually decrease. The optical transceiver modules are required to support more functions on limited or decreasing PCB areas.
In one aspect, developments in telecommunication and data communication require more and more functions be included on the PCB of an optical transceiver module. But the modular shape of an optical transceiver module and its corresponding interface agreement limit the usable area of the PCB. One possible solution for this usable area limitation problem is to decrease the Integrated Circuit (IC) chip sizes on the PCB by using a newer and more advanced IC technology with deeper sub-micron transistors. Another solution is to combine functions on different IC chips into one single IC, making a System-on-a-Chip (SOC) IC. These solutions however rely on the developments of new IC chips, which is costly and time consuming.
In another embodiment, as shown in
A Printed Circuit Board is typically a flat board that holds integrated circuit chips and other electronic components. The board comprises multiple layers (typically 2 to 10) of electronic components that are interconnected via metallic pathways. The first Printed Circuit Board 210 n a system is called a “system board” or “motherboard,” while smaller ones that plug into the slots in the first board are called “boards” or “cards.” In one embodiment, the first Printer Circuit Board 210 having a first function circuit is connected to a plurality of second Printed Circuit Boards 220 each comprising a second function circuit that are electrically connected to the first function circuit.
As shown in
The first PCB 210 and the second PCB 220 can be connected in different arrangements. In one embodiment, the first Printed Circuit Board 210 is a mother board and the second Printed Circuit Board 220 a daughter board as specified by the ISA (Industry Standard Architecture) requirements for a daughter board on a mother board. In another embodiment, as shown in
In another embodiment, as shown in
Another implementation is shown in
Yet another implementation is shown in
Integrated circuit devices for modem telecommunication and data communication applications may operate at frequencies in the range of gigabits per second. Digital signal processing at such high frequencies tends to create interference in different parts of the circuit. The interference between the transmission circuit and the reception circuit are prune to error generation and is especially undesirable. The configuration of the Printed Circuit Boards in the optical transceiver module 100 in the present invention reduces the interference by creating a shield between the transmission circuits and the reception circuits.
As shown in
In another embodiment, when the second Printed Circuit Board 220 is assembled into the optical transceiver module 100, its bottom of the second Printed Circuit Board 220 touches the case body 110 of the optical transceiver module 100, and the top of the second Printed Circuit Board 220 is in contact with the sheet metal cover 120 of the optical transceiver module 100. These contacts close the gaps between the second Printed Circuit Board 220 and the case body 110 and its sheet metal cover 120, which further reduces the electromagnetic interference between the transmission and the reception paths.
The Printed Circuit Board configurations described above are compatible with modular shaped applications wherein the module's vertical extension is high enough to allow a second portion of the Printed Circuit Board. In particular, the Printed Circuit Board configuration is applicable to Small Form Factor (SFF) type optical transceiver modules, Small Form-factor Pluggable (SFP) type optical transceiver modules, Bi-directional Small Form-factor Pluaggable (Bi-di SFP) type optical transceiver modules, and other types of optical transceiver modules.
An optical transceiver module having the Printed Circuit Board configuration disclosed in the present invention possesses great advantages over an optical transceiver module having an ordinary Printed Circuit Board. The more usable area allows an optical transceiver module to hold more functions in the module. In addition, the electromagnetic interference between the transmission and reception circuits is reduced.
The first Printed Circuit Board and the second Printed Circuit Board are connected together with mating the two boards along rabbet(s) and soldering. The method is reliable, easy to implement, and cost effective. The method also allows more usable area on the first Printed Circuit Board and compact working space, compared to a mother board/daughter board method.
Although specific embodiments of the present invention have been illustrated in the accompanying drawings and described in the foregoing detailed description, it will be understood that the invention is not limited to the particular embodiments described herein, but is capable of numerous rearrangements, modifications, and substitutions without departing from the scope of the invention. The following claims are intended to encompass all such modifications.
Part Numbers
The present invention is related to commonly assigned U.S. patent application Ser. No. 10/741,805, filed on Dec. 19, 2003, titled “Bi-directional optical transceiver module having automatic-restoring unlocking mechanism”, commonly assigned U.S. patent application Ser. No. 10/815,326, filed on Apr. 1, 2003, titled “Small form factor pluggable optical transceiver module having automatic-restoring unlocking mechanism and mechanism for locating optical transceiver components”, and commonly assigned Chinese Patent Application No. 200420033096.3 filed on Mar. 4, 2004, titled “Printed Circuit Board for Small Form Factor Optical Transceiver”. The disclosures of this related application are incorporated herein by reference.
