Patent Application
20140056557
1. Field of the Invention
The present invention relates to an optical module, and more particularly to an optical module for improving optical signal transmission.
2. Description of Related Arts
An optical transceiver is used in optical networking for conversion between an optical signal and an electrical signal.
Generally, an optical transceiver comprises an optical module having a TOSA (Transmitter Optical Subassembly) for receiving an optical signal converted from an electrical signal by a VCSEL and transmitting the optical signal to a waveguide, and a ROSA (Receiver Optical Subassembly) for receiving an optical signal from another waveguide and transmitting the optical signal to a photodiode which converts the optical signal to an electrical signal. Between the optical signal from the VCSEL to the waveguide and the optical signal from the another waveguide to the photodiode are needed two lenses for handling the optical signals.
U.S. Pat. No. 8,195,017 discloses a consumer input/output (CIO) optical transceiver module for use in an active optical cable. The transceiver module includes two singlet laser diodes and two singlet photodiodes in a row, instead of costly parallel arrays of laser diodes and parallel arrays of photodiodes that are used in known active optical cables, for providing two high-speed transmit channels and two high-speed receive channels, respectively. Correspondingly arranged is an optics system module having lenses formed therein for coupling light between optical fibers and the laser diodes and the photodiodes.
U.S. Pat. No. 7,212,698, issued to Bapst et al. on May 1, 2007, discloses a method of processing a circuit board having one or more associated optical waveguides, comprising providing and using one or more etch stop layers in proximate to the one or more waveguides to provide one or more cavities having a defined positioning and depth for alignment of one or more optical components. The optical component is selected from the group consisting of opto-electronic modules, lenses, turning mirrors and/or their combination. Also disclosed is staggering of turning mirrors and lenses to increase waveguide density.
An object of the present invention is to provide an improved optical module. To achieve the this object, an optical module comprises: a housing; a first incident surface mounted on the housing for receiving an optical signal converted from an electrical signal; a first output surface mounted on the housing for exporting the optical signal from the first incident surface; a second incident surface mounted on the housing for receiving another optical signal to be converted to another electrical signal; and a second output surface mounted on the housing for exporting the another optical signal from the second incident surface. An aperture of the first incident surface is smaller than an aperture of the second incident surface.
Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings.
Reference will now be made in detail to a preferred embodiment of the present invention.
Referring to
Referring to
The first lens array 20 and the second lens array 30 parallel to the second lens array 20 are mounted on the housing 10. The first lens array 20 and the second lens array 30 are vertical to two pairs of flanges 112. The first lens array 20 has a number of first lenses 2 arranged in a row. The second lens array 30 has a number of second lenses 3 arranged in a row. The housing 1 is molded on the periphery of the first lens array 20 and the second lens array 30. From a view of a vertical direction of the first and second lens arrays 20, 30, the first lenses 20 and the second lenses 30 are staggered each other. Each first lens 2 has a first incident surface 21 for receiving the optical signal transmitting into the lens 2 and a first output surface 22 for exporting the optical signal transmission from the lens 2. The first incident surface 21 and the first output surface 22 are mounted or constituted on the housing 1. The first incident surface 21 and the first output surface 22 are respectively a curved surface which belong to an elliptical or circle structure and bulged outwardly. The curved surface may be a convex lens. The mid portions of the first incident and output surface 21, 22 are bulged highest. Each second lens 3 has a second incident surface 31 for receiving an optical signal transmitting into the second lens 3 and a second output surface 32 for exporting the optical signal transmission from the second lens 3. The second incident surface 31 and the second output surface 32 are mounted or constituted on the housing 1, too. The second incident surface 31 and the second output surface 32 are respectively similar to the structures of the first incident and output surface 21, 22, that is an curved surface of the second incident or output surface 31, 32 which belong to an elliptical or round structure and bulged outwardly. The curved surface can be another convex lens. The mid portions of the second incident and output surface 31, 32 are bulged highest. In other embodiments, the first incident and output surface 21, 22 may be not formed on a lens 2, the first incident and output surface 21, 22 are formed on two different lenses. The second incident or output surface 31, 32 are formed on two different lenses. The first incident and output surface 21, 22 and the second incident or output surface 31, 32 are exposed from the first and second surface 11, 12 of the housing 1, respectively.
The first incident surface 21 of the first lens 2 and the second output surface 32 of the second lens 3 are located on a first surface 11 of the housing. The first output surface 22 of the first lens 2 and the second incident surface 31 of the second lens 3 are located on a second surface 12 of the housing 1. An approximately 45 degrees angle is formed between the first incident surface 21 and first output surface 22 of the first lens 2, and an approximately 45 degrees angle is formed between the second incident surface 31 and second output surface 32 of the second lens 3.
When the optical module 100 is used for the optical transmitter or transceiver, and the optical transmitter or transceiver is needed to an optical signal be converted from an electrical signal, the optical signal be converted from the electrical signal by a vertical cavity surface emitting laser (VCSEL) firstly, the first incident surface 21 receives the optical signal from VCSEL mounted on the first surface 11 of the housing 1, and the optical signal goes through the first lens 2 and exports the first output surface 22 toward a waveguide, secondly. When the optical transmitter or transceiver is needed to an optical signal be converted to an electrical signal, the optical signal which comes from electrical signal is converted to by another waveguide is sent toward a photodiode, the second incident surface 31 receives the optical signal from the waveguide mounted on the second surface 12 of the housing 1, and the optical signal goes through the second lens 3 and exports the second output surface 32 toward the photodiode.
The term “aperture” refers to the size of receiving an optical signal or handling the optical signal. If the incident or output surface of first or second lens 2, 3 is circle, the aperture is as the diameter of the incident or output surface; and if the incident or output surface is elliptical, the aperture is as the area of the incident or output surface. After divergence optical signal is received by the aperture of the first or second incident surface 21, 31, the optical signal can be parallel to each other or gather inwardly. After the divergence optical signal is received by the area of the outside of the aperture of the first or second incident surface 21, 31, the divergence optical signal is still divergence outwardly, and of which angle is increased. Due to the VCSEL providing a small hole to emit the optical signal, and the divergence angle of the optical signal from the VCSEL is small. So, the small aperture of the first incident surface 21 is provided to receive the small divergence angle optical signal. After the parallel or gathering the optical signal in the lens 2 being exported by the first output surface 22, the optical signal can gather inwardly again or focus on a point and transit toward the waveguide. The hole of the VCSEL is vertical to the first and second surface of housing 1, and the hole of the waveguide is extending along the first and second surface of housing 1. Through the optical signal is sent by the first lens 2 and the second lens 3, the route of optical signal before the first or second lens 2, 3 is vertical roughly to the route the route of the optical signal which is exported from the first or second lens 2, 3.
Due to the waveguide providing a bigger hole than the VCSEL to emit an optical signal, the divergence angle of the optical signal from the waveguide is bigger. So, the aperture of the second incident surface 31 bigger than the first incident surface's 21 is provided to receive the bigger divergence angle optical signal. After the parallel or gathering the optical signal in the second lens 3 being exported by the second output surface 32, the optical signal can gather inwardly again or focus on a point and transit toward the photodiode. As the divergence angle or area of the optical signal sent by the first lens 2 is smaller than second lens 3, as the aperture of the first output surface 22 of the first lens 2 is smaller an aperture of the second output surface 32 of the second lens 3.
According to the divergence angle that the optical signal arrival at the first or second incident 21, 31 of the lenses 2, 3, the optical module 100 is confirmed that the aperture area of the first lens 2 or second lens 3. The optical module 100 has a big aperture for receiving the big divergence angle of the optical signal, and has a small aperture for receiving the small divergence angle of the optical signal.
It is to be understood, however, that even though numerous characteristics of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
