Optical waveguides – With disengagable mechanical connector – Optical fiber to a nonfiber optical device connector
Reexamination Certificate
1999-05-10
2001-09-04
Font, Frank G. (Department: 2877)
Optical waveguides
With disengagable mechanical connector
Optical fiber to a nonfiber optical device connector
C385S092000, C385S088000
Reexamination Certificate
active
06283644
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention pertains generally to optical transceivers and, in particular, to an optical device package for an optical transceiver.
2. Discussion of the Background
Optical transceivers are known in the art and include active optical devices or diode packages. Common diode packages include LED packages such as a TO-46 package or a 5.6 mm TO style laser diode package such as RLD-85PC diode package by Rohm, Incorporated. These diode packages or TO cans typically include a metallic housing having a laser diode or LED for transmitting data and a photo diode for performing power-monitoring, metal contact leads exiting from the diodes for connection to a power source and a cover glass opposed to the diode, through which the energy is transmitted. The TO can is hermetically sealed. The hermetic sealing of the TO can is a time-consumsing and expensive process which adds to the overall expense of the LED or laser package. As well, the commonly known TO cans do not have the emission area of the diode aligned within the TO can in a consistently centered orientation. Thus, placement of the TO can in a uniform position does not provide for alignment of the diode to an optical connector and maximum power transmission is not achieved. Thus, alignment of the TO package becomes a time-consuming and expensive process.
Commonly known housings for optical transceivers require complex mechanical means in order to align the diode package, the lens, the bore and the optical waveguide ferrule. Mechanical means, such as a screw is commonly used to actively align the TO can within the housing.
Further, a molded plastic housing is often used having precision molded cavities specifically sized for receiving a diode package, another cavity specifically sized for receiving a lens and another cavity specifically sized for receiving an optical waveguide ferrule. Such an optical transceiver housing is often rendered ineffective in production due to variations in the alignment of the LED or laser relative to the TO can.
Often, optics housings are metallic so as to provide ruggedness, ease of machining complicated shapes, and to enhance shielding of electromagnetic fields. Ferrules connect to the optical package by way of inserting the ferrule into the optics housing. Attached to the ferrule is the fiber optic cable. The fiber optical cable conveys the optical signal. The optical package can either receive or create the optical signal and as such either transforms the received optical signal into an electrical signal or transforms an electrical signal into an optical signal. Presently, the majority of ferrules which are inserted into the optics housings are made of a ceramic material. To properly transmit the optical signal, the ferrule must be accurately positioned within the optics housing. The close fit between the metallic housing and the ceramic ferrule has resulted in a failure mode known as galling. Galling results in large amounts of material transfer between one or both of the contacting surfaces. At a certain point, the galling phenomenon is so insidious that it prevents the ferrule from being further inserted into the housing or from being removed from the housing of the optics housing. In order to prevent the galling phenomenon it has been known to provide a sleeve or insert in the housing so as to receive the ferrule, where the sleeve is made of a material similar to the material of the ferrule. Machining a ceramic material to exacting dimensional requirements is difficult and hence is expensive. The scrap rate is high and the time required to process such ceramic sleeves is high. The sleeves are machined to exacting dimensions since the ferrule must be received within the sleeve with very little clearance between the two so as to accurately position the ferrule within the optics housing. Since both the ceramic ferrule and the ceramic sleeve are not very compliant, the dimensions of the sleeve and the ferrule must be very accurate.
In view of the above, it is an object of the present invention to provide an optical device package which is quickly and inexpensively manufactured.
It is a further object of the present invention to provide an optical device package which may be easily aligned with an optical transceiver housing.
It is another object of the present invention to provide an optical package having a single optical axis.
It is another object of the present invention to provide an optical package housing formed using insert molding techniques in order to provide a quickly and inexpensively manufactured precision housing assembly.
It is still yet another object of the invention to provide an optical device package having a sleeve which prevents galling and is inexpensively manufactured.
SUMMARY OF THE INVENTION
A principal object of this invention is to provide an optical package comprising a housing including a bore for receiving an optical waveguide and a focusing element adjacent the bore, the bore and the focusing element being aligned along a common optical axis, a diode mounted to a substrate adjacent the focusing element and an alignment means associated with the housing for aligning the substrate along the optical axis. The alignment means may include a trace located in a predetermined position on the substrate to which the housing is mounted. The alignment means may include a groove located in a predetermined position on the substrate to which the housing is mounted. The housing may include an outer sleeve defining the bore for receiving an optical waveguide and an inner sleeve for receiving the focusing element. The inner sleeve may include a lens support means for mounting the focusing element. The focusing element may be mounted in a lens support means. The lens support means may include a plastic washer having a bore of a diameter less than the diameter of the focusing element. The focusing element may be a ball lens. The groove may be formed between conductive traces adhered to the substrate. The groove may be integrally molded with the substrate. The bore may have a diameter of approximately 0.0984 inches or greater. The height of the inner sleeve may be less than the height of the outer sleeve. The inner sleeve may be partially filled with an optical filler composition. The alignment means may include a precision formed aperture in the housing for receiving the substrate. The substrate may be a precision formed material having a predetermined size and the diode mounted thereto in a predetermined orientation on the substrate. The focusing element may be integrally molded with the housing. The housing and the focusing element may be formed of a transmissive material allowing for the transmission of wavelengths from 780-1350 nanometers.
In an embodiment, an optical package is provided comprising a substrate having a diode mounted thereto and a groove formed in the substrate surrounding the diode, an inner sleeve mounted within the groove having a lens therein and an outer sleeve mounted to the substrate surrounding the inner sleeve for receiving an optical ferrule. The groove may be formed between conductive traces adhered to the substrate. The groove may be integrally molded with the substrate. The inner sleeve may include a tab protruding within the sleeve to provide support to the lens. The inner sleeve may be formed of stainless steel, brass, nickel silver or ARCAP®. The outer sleeve may have a cylindrical shape and include a bore having an inner diameter of 0.0984 inches or greater. The height of the inner sleeve may be less than the height of the outer sleeve. The diode may be a surface emitting diode. The diode may be an LED. The diode may be a vertical cavity surface emitting laser (VCSEL). The diode may be a photodiode. The inner sleeve may be partially filled with an optical filler composition. The optical filler composition may be an epoxy or a silicone composition. The optical filler composition may form a meniscus at the base of the lens to provide retention of the lens. The tabs of the inner sleeve may be form
Erickson Scott
Gilliland Patrick B.
Shatskin Leonid
Washburn Theodore
Weiss Roger
Font Frank G.
Kovach Karl D.
Mooney Michael P.
Newman David L.
Stratos Lightwave, Inc.
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