Patent Application
20050135756
This disclosure relates to electro-optical devices, specifically, a bi-directional optical transceiver module for point-to-point fiber-to-the-home applications.
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.
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.
In one aspect, the present application discloses an optical transceiver module comprising
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.
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.
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
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
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
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
The housing of the optical transceiver module 100, shown as part 110 in
The optical interface 130 is shown in
The locking mechanism comprises a triangular shaped locking detent 140 as shown in
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
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
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
