Bi-directional optical transceiver module having automatic-restoring unlocking mechanism

Abstract

An optical transceiver module includes a housing comprising a first end and a second end, an electrical interface associated with the first end adapted to be locked into a receiving cage, and an optical interface associated with the second end. The optical transceiver module also includes a locking mechanism that can lock the optical transceiver module to a receiving cage and an automatic-restoring mechanism. The automatic-restoring unlocking mechanism comprises a sliding plate, an unlocking lever, and a restoration spring. The automatic-restoring unlocking mechanism automatically restores the sliding plate to the normal position after the optical transceiver module is unlocked from the receiving cage.

Description

TECHNICAL FIELD

This disclosure relates to electro-optical devices, specifically, a bi-directional optical transceiver module for point-to-point fiber-to-the-home applications.

CROSS-REFERENCES TO RELATED INVENTIONS

The present invention is related to commonly assigned Chinese Patent Application with Application No. 03250206.0, filed on Sep. 5, 2003, titled “Bi-directional Transceiver Module”. The disclosures of this related application are incorporated herein by reference.

BACKGROUND

A bi-directional optical transceiver module is a telecommunication device that can receive optical signals, convert the received optical signals into electrical signals, and output the electrical signals. Simultaneously, the bi-directional optical transceiver module can also receive electrical signals, convert the received electrical signals into optical signals, and output the optical signals. The receiving and transmitting of the optical signals are carried on a single optical fiber. A common bi-directional optical transceiver module may use one of several different housing formats including the corresponding electrical interfaces of the housing formats. For example, there are the Small Form-factor Pluggable (SFP) housing format, the Small Form Factor (SFF) housing format, and the 1×9 transceiver (a module structure by Lucent) housing format. The optical interface for transmitting and receiving optical signals may exist in different types. For example, there are SC (Subscriber Connector) connectors, ST (Straight Tip) connectors, FC (Fiber Connector) connectors, and LC (A Small Form Factor connector designed by Lucent with a profile similar an RJ-45 connector) connectors.

When an optical transceiver module is used in applications, it is plugged into a receiving cage and is locked inside the receiving cage with a lock mechanism. In most prior art optical transceiver modules, the sliding plate of the locking mechanisms need to be manually restored to its original position after the optical transceiver module is unlocked. If the manual step is skipped, the optical transceiver modules may still remain in the unlocked condition, making the optical transceiver module unsafe and unreliable for operation. Some other prior art systems have made attempts to eliminate this manual restoration step. But the prior art systems remain to be complex, expensive to manufacture, and not easy to use.

SUMMARY

In one aspect, the present application discloses an optical transceiver module comprising

• • a) a housing comprising a first end and a second end;
  • b) an electrical interface associated with the first end adapted to be locked into a receiving cage;
  • c) an optical interface associated with the second end;
  • d) a locking mechanism that can lock the optical transceiver module to a receiving cage; and
  • e) an automatic restoring unlocking mechanism comprising a sliding plate, an unlocking lever, and a restoration spring, wherein the automatic restoring unlocking mechanism automatically restores the sliding plate to the normal position after the optical transceiver module is unlocked from the receiving cage.

In another aspect, the present invention provides a practical new type of bi-directional optical transceiver module, including one case body, one sheet metal cover fixed on one end of the case body, one case cover fixed on the other end of the case body, one electrical interface and one optical interface situated at the two ends of the case body respectively and an automatic-restoring unlocking mechanism located on the case cover. The optical transceiver module can be easily unlocked and automatically restored to its normal position after being unlocked from the receiving cage.

In yet another aspect, the present application provides a bi-directional optical transceiver module that has an automatic-restoring unlocking mechanism that automatically restores the sliding plate back to its normal condition after the optical transceiver module is unlocked. This capability allows the optical transceiver module to be always in its normal state.

In still another aspect, the invention bi-directional optical transceiver module is inexpensive to manufacture, of high performance-to-price ratio, high reliability, and convenient to install and maintain. It can be desirably applied to a point-to-point fiber-to-the-home system.

In another aspect, the present application provides a bi-directional optical transceiver module that includes an SFP agreement electrical interface, and an SC standard optical interface that can be connected with a single optical fiber having an SC standard connector.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of the optical transceiver module in accordance with the present invention.

FIG. 2 is a detailed perspective view of the optical interface of the fiber optical transceiver module of FIG. 1.

FIG. 3(a) is a cross sectional view of the unlocking mechanism along the line A-A in FIG. 1.

FIG. 3(b) is a cross sectional view of the unlocking mechanism along the line B-B of FIG. 1.

DETAILED DESCRIPTION

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.

Bi-directional fiber optical transceiver modules are widely used in telecommunication networks. An optical transceiver module receives optical signals, converts the received optical signals into electrical signals and transmits the electrical signals. Such an optical transceiver module also simultaneously receives electrical signals, converts the received electrical signals into optical signals and transmits the optical signals. The receiving and transmitting of the optical signals are carried typically on a single optical fiber although the present invention is compatible with more than one optical fiber. A typical optical transceiver module comprised a housing, a first end associated with an electrical interface, a second end associate with an optical interface, a locking mechanism, and an unlocking mechanism.

An optical transceiver module is subject to various industry standards and agreements between common vendors. The electrical interface of such an optical transceiver module is required to be SFP compliant. The housing of an optical transceiver module needs to abide by SFP agreement. The optical interface is compliant with SC standard. In particular, there is not a standard mechanism to lock an optical transceiver module into a secured position inside a receiving cage where the optical transceiver module is connected to a fiber optical network on its second end and connected to an electrical interface of an equipment on its first end.

FIG. 1 is a perspective view of the optical transceiver module 100 in accordance with the present invention. The optical transceiver module 100 comprises a housing 110 with a first end associated with an electrical interface 120, a second end associated with an optical interface 130, a locking mechanism that can lock the first end of the optical transceiver module to a receiving cage, and an automatic-restoring unlocking mechanism 150. The automatic-restoring unlocking mechanism 150 comprises a sliding plate 151, an unlocking lever 152, and a restoration spring 154. The automatic-restoring unlocking mechanism 150 automatically restores the sliding plate 151 to the normal (or the ready-to-lock) position after the optical transceiver module 100 is unlocked from the receiving cage either before or after the optical transceiver module 100 is unplugged (i.e. released) from the receiving cage.

In accordance with the present invention, the locking mechanism includes a triangular shaped locking detent 140. In operation, the optical transceiver module 100 is first plugged into a receiving cage. The receiving cage (not shown) houses a first end associated with an electrical interface, which typically complies with the SFP agreement. When the optical transceiver module 100 is slid into the receiving cage (not shown), the triangular shaped locking detent 140 locks into a locking hole of the receiving cage and secures the position of the optical transceiver module 100 inside the receiving cage. The electrical interface (the copper foil strips, see below) comes into contact with the electrical interface in the receiving cage. The first end of the optical transceiver module 100 comprises an electrical interface shown as part 120 in the left half part of FIG. 1, a printed circuit board 121, (shown in FIG. 2, not visible in FIG. 1) the sheet metal cover 113, and 20 copper foil strips 122. The electrical interface's physical dimensions and the 20 copper foil strips 122 are compliant with SFP agreement.

When the optical transceiver module 100 needs to be replaced, an unlocking mechanism is needed to unlock the optical transceiver module 100 from the receiving cage. The unlocking mechanism on the optical transceiver module 100 includes a sliding plate 151 with a wedge shaped part on one end of the sliding plate (shown in FIG. 1). The wedge angle is between 0 and 90 degrees (for example, 45 degrees). When the sliding plate 151 is slid toward the receiving cage, the wedge shaped part of the sliding plate 151 pushes the receiving cage upward, thus releasing lock of the optical transceiver module 100 from the receiving cage.

One problem with the unlocking mechanism is, there is not a common agreement on how to restore the sliding plate 151 to its normal position from its inward position after the unlocking of the optical transceiver module 100 takes place. Without such an automatic-restoring unlocking mechanism 150 for the sliding plate 151, friction forces between the sliding plate 151 and the rails the sliding plate 151 slides along can keep the sliding plate 151 from returning to its normal position. Without the sliding plate 151 in its normal position, the optical transceiver module 100 is not in a locking condition, as the optical transceiver module 100 cannot be locked in a receiving cage. Therefore, a step of manually restoring the sliding plate 151 is required.

This invention application introduces an automatic-restoring unlocking mechanism that restores the sliding plate 151 to its normal (or ready-to-lock) condition immediately after the optical transceiver module 100 is unlocked from a receiving cage, thus making the optical transceiver module 100 always in normal condition.

In another aspect, as mentioned earlier, an optical transceiver module may have a various possibility for its optical interface. The optical transceiver module 100 described in this invention application uses an SC standard optical interface.

The structure of the optical transceiver module 100 is illustrated in FIG. 1. The optical transceiver module 100 contains five major components: (1) a housing 110; (2) a first end associated with an SFP agreement compliant electrical interface 120; (3) a second end associate with an SC standard compliant optical interface 130; (4) a locking mechanism having a triangular shaped locking detent 140, and (5) an automatic-restoring unlocking mechanism 150.

The following terms are hereby defined in the present application. An inward direction is the direction pointing from the optical interface toward the electrical interface. An outward direction is the direction from the electrical interface toward the optical interface. The left side of the optical transceiver module 100 is the side of the electrical interface and the right side of the optical transceiver module 100 is the side of the optical interface. The up side of the optical transceiver module 100 is the side of the optical transceiver module 100 that can be seen in FIG. 1. The down side of the optical transceiver module 100 is the opposite side of the up side of the optical transceiver module 100.

The housing of the optical transceiver module 100, shown as part 1 10 in FIG. 1, comprises a case body 111, a case cover 112 attached to the case body 111 on the optical interface side of the optical transceiver module 100, and a sheet metal cover 1 13 on the case body 11 1. The case cover 112 covers the optical interface of the optical transceiver module. The sheet metal cover 1 13 covers the main part of the optical transceiver module 100, including the printed circuit board 121, optical transceiver component 131 and electrical interface of the optical transceiver module 100.

The optical interface 130 is shown in FIG. 2. Preferably, the optical interface 130 is SC standard compliant. It contains an optical transceiver component 131, a SC standard compliant single-entry plastic clip 132, and a case cavity 133. The optical transceiver component 131 is under the case cover 112. The SC standard compliant single-entry plastic clips 132 are located inside the case cavity 133. The case cavity 133 and the SC agreement compliant single-entry plastic clip 132 are used to secure a correct connection between the SC connector of the input optical fiber and the optical transceiver component 131. The case cavity 133 is located at the end of the optical transceiver module 100. It is used to hold and protect the parts of the optical interface. The optical transceiver component 131 can convert optical signals to electric signals, and vice versa (i.e. bi-directional mode) to allow the optical transceiver module 100 to receive and transmit signals from the either the electric interface 120 and the optical interface 130. The optical transceiver module 100 can operate at one or two optical wavelengths, and transmit and receive optical signals on a single optical fiber.

The locking mechanism comprises a triangular shaped locking detent 140 as shown in FIG. 1. The triangular shaped locking detent 140 is attached to the sheet metal cover 113, as shown in FIG. 1. The function of the triangular shaped locking detent 140 is to lock the optical transceiver module 100 into a receiving cage and secure its position during the receiving and transmitting of optical and electrical signals. Before the optical transceiver module 100 can be put into a working condition, it is slid into a receiving cage (not shown). For an SFP agreement compliant receiving cage, the triangular shaped locking detent 140 pushes the upper section of the receiving cage upward until it meets a part of the receiving cage where there is a locking hole fitting the triangular shaped locking detent 140. With the triangular shaped locking detent 140 fitting into the locking hole, the upper section of the receiving cage falls down, locking the optical transceiver module 100 to a secured position. When optical transceiver module 100 is slid into the receiving cage, only the first end of the optical transceiver module 100 slides into the receiving cage. The optical interface 130, covered by the case cover 112 is left outside the receiving cage.

The automatic-restoring unlocking mechanism of the optical transceiver module 100 relies on a rotation of an unlocking lever 152 from its normal position. The normal position of the unlocking lever 152 is illustrated in FIG. 1. When the unlocking lever 152 is rotated around the shaft 156 (shown in FIG. 3(b)) attached to the case cover 112 from its normal position, it pushes the sliding plate 151, which slides along rails 157 (shown in FIG. 3(b)) that are attached to the case cover 112, inward. As the sliding plate 151 moves inward, its wedge shaped part pushes the upper section of the receiving cage upward to allow the triangular shaped locking detent 140 to be released from the locking hole of the receiving cage. The relative dimensions of the wedge shaped part of the sliding plate 151 and the triangular shaped locking detent 140 are such that the pushing of sliding plate 151 can produce enough upward movement to allow the release of the triangular shaped locking detent 140 from the receiving cage. This allows the optical transceiver module 100 to be pulled out of the receiving cage.

After the optical transceiver module 100 is unlocked, the sliding plate 151 usually still remains in the unlocking position. The optical transceiver module 100 cannot be properly locked unless the sliding plate 151 is restored to its normal position. The normal position of the sliding plate 151 is hereby defined as the position such that the edge of the wedge shaped part of the plate is near the left side of the case cover 112. A restoration spring 154 under the sliding plate 151 is used to automatically restore the sliding plate 151 to its normal position. The restoration spring 154, shown in FIG. 3(a), is hitched to a spring-locking pin 155. When the sliding plate 151 moves inward (to the left in FIG. 3(a)), a spring baffle 153, which is attached to the sliding plate 151, also moves inward. The spring baffle 153 presses the restoration spring 154 in this movement. When the optical transceiver module 100 is released from the receiving cage, the unlocking lever 152 is released, which releases the pressing force on the restoration spring 154. The restoration spring 154 expands back, pushing the spring baffle 153 outward. This movement in turn causes the sliding plate 151 to move outward. The movement of the sliding plate 151 causes the unlocking lever 152 to rotate back to its normal position. If the optical transceiver module 100 is out of the cage, the optical transceiver module 100 is now ready to be locked again. If the optical transceiver module 100 still operates in the cage, the optical transceiver module 100 is locked again by the automatic-restoring mechanism.

The present invention provides an advantageous optical transceiver module compared to the prior art systems. U.S. patent Publication No. US1103/0201543A1 titled “Pluggable optical transceiver with push-pull actuator release collar”, for example, discloses a mechanism having a push-pull actuator release collar. The system disclosed in the present invention possesses the following advantages compared to the mechanism having the push-pull actuator release collar,: First, the automatic-restoring unlocking mechanism in the present invention is more reliable than the above prior art mechanism using a push-pull actuator release collar. The invention mechanism makes use of a restoration spring to restore the normal position of an optical transceiver module that is more reliable and long lasting than the pair of leaf springs used in the prior-art mechanism. Secondly, the invention mechanism having a single restoration spring is less expensive than the above prior-art mechanism. Thirdly, the invention mechanism is easier to use than the above prior-art mechanism. The invention mechanism relies on a rotation of the unlocking lever 152 to release the optical transceiver module 100, which is much easier than the prior-art mechanism that requires the pushing of a rectangle shaped actuator collar to release the optical transceiver module 100. Fourth, the invention mechanism having the single restoration spring 154 to its spring-locking pin 155 is easier to manufacture than attaching a pair of leaf springs to the actuator release collar in the prior art mechanism. Fifth, the optical transceiver module 100 in this invention is capable of receiving and transmitting optical signals on a single optical fiber. Compared with two optical fibers used by the prior art, a single optical fiber makes it possible for higher packaging densities and lower costs in applications.

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

• 100 optical transceiver module
• 110 housing
• 111 case body
• 112 case cover
• 113 sheet metal cover
• 120 electrical interface
• 121 printed circuit board
• 122 copper foil strips
• 130 optical interface
• 131 optical transceiver component
• 132 SC agreement standard compliant single entry plastic clip
• 133 case cavity
• 140 triangular shaped locking detent
• 150 automatic-restoring unlocking mechanism
• 151 sliding plate
• 152 unlocking lever
• 153 spring baffle
• 154 restoration spring
• 155 spring-locking pin
• 156 shaft
• 157 rail

Claims

1. An optical transceiver module, comprising

a) a housing comprising a first end and a second end;

b) an electrical interface associated with the first end adapted to be locked into a receiving cage;

c) an optical interface associated with the second end;

d) a locking mechanism that can lock the optical transceiver module to a receiving cage; and

e) an automatic-restoring unlocking mechanism comprising a sliding plate, an unlocking lever, and a restoration spring, wherein the automatic restoring unlocking mechanism automatically restores the sliding plate to the normal position after the optical transceiver module is unlocked from the receiving cage.

2. The optical transceiver module of claim 1, wherein the sliding plate includes a wedge shaped part on one end and said sliding plate is attached to a spring baffle.

3. The optical transceiver module of claim 2, wherein the wedge angle of the wedge shaped part is between 0 and 90 degrees.

4. The optical transceiver module of claim 1, wherein the electrical interface complies with the Small Form-factor Pluggable (SFP) agreement.

5. The optical transceiver module of claim 1, wherein the optical interface complies with the Subscriber Connector (SC) agreement.

6. The optical transceiver module of claim 1, further comprising an optical transceiver component that transmits and receives electrical signals and optical signals.

7. The optical transceiver module of claim 6, wherein the optical transceiver component transmits and receives optical signals at one or two wavelengths on a single optical fiber.

8. The optical transceiver module of claim 6, wherein the optical transceiver component operates in a bi-directional mode.

9. The optical transceiver module of claim 1, wherein the electrical interface comprises

a) a sheet metal cover;

b) a printed circuit board under the sheet metal cover; and

c) 20 copper foil strips on the printed circuit board.

10. The optical transceiver module of claim 1, further comprising an external body that comprises:

a) a case body on the optical interface end of the optical transceiver module body; and

b) a case cover attached to the case body that covers the optical interface portion of the case body.

11. The optical transceiver module of claim 10, further comprising

a) an optical transceiver component under the case cover;

b) a case cavity at the second end of the optical transceiver module; and

c) a Subscriber Connector (SC) agreement compliant single entry plastic clip inside the case cavity.

12. The optical transceiver module of claim 10, wherein the automatic-restoring unlocking mechanism further comprises

a) a shaft attached to the case cover;

b) two rails attached to the case cover; and

c) a spring-locking pin attached to the case cover.

13. The optical transceiver module of claim 10, wherein the unlocking lever pushes the sliding plate to unlock the optical transceiver module when the unlocking lever rotates around the shaft.

14. The optical transceiver module of claim 10, wherein the sliding plate slides along the rails.

15. The optical transceiver module of claim 11, wherein the restoration spring is fixed on one end of the spring-locking pin.

16. The optical transceiver module of claim 1, wherein the locking mechanism comprises a triangular shaped locking detent for the locking of the optical transceiver module.

17. The optical transceiver module of claim 1, wherein the length of the optical transceiver module is about 63 mm.

18. The optical transceiver module of claim 1, wherein the automatic-restoring unlocking mechanism automatically restores the sliding plate to the normal position after the optical transceiver module is unlocked and unplugged from the receiving cage.