Abstract:
A multiband wavelength multiplexed optical device for bidirectional communication over one light path. The device may use dichroic filters or reflectors, or other mechanisms for wavelength or bandwidth separation or discrimination of sent or received light signals. It may have a multitude of light sources and detectors for sending and receiving light signals such as those for optical-based communications, controls and so forth. For instance, the optical device may be utilized in transceiver systems.

Description:
BACKGROUND  
         [0001]    The invention relates to optical communication and more particularly to bidirectional communication on an optical link or network. Such optical communications are becoming more significant in the communications field. New standards may be emerging relating to such communication.  
         SUMMARY  
         [0002]    The invention is an optical assembly or sub-assembly that may easily couple light of one wavelength to a single light wave guide and receive light of the same wavelength or another wavelength from the same waveguide at the same time. The assembly includes opto-electronic components for emitting and detecting light signals to and from the wave guide, in a form factor that is compatible with typical two-fiber receiver assemblies. 
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0003]    [0003]FIG. 1 reveals a bidirectional multiband optical device using a wavelength filter.  
         [0004]    [0004]FIG. 2 shows a bidirectional multiband optical device using a wavelength reflector.  
         [0005]    [0005]FIG. 3 illustrates a multiple wavelength or bandwidth bidirectional optical device having multiple components utilizing wavelength or bandwidth discriminators.  
         [0006]    [0006]FIG. 4 shows an electrical/optical transceiver signal system. 
     
    
     DESCRIPTION  
       [0007]    [0007]FIG. 1 is a basic diagram of a bidirectional multiband optical assembly  10 . Light  11  of a first wavelength may be emitted by light source  17 , which may be reflected at points  15  and  14  and exit optical port  13 . Light source  17  may be a VCSEL outputting light  11  that may modulated in one form or another with communication signals or the like. These functions may be accomplished with an electronics module  66  that is connected to source  17 . Source  17  may be another kind of device as appropriate for an application of the assembly. Light  11  may have other wavelengths, besides the first wavelength, which may be filtered out by a filter or mirror. Points  15  and  14  are where light is reflected and may be mirrors that are discrete or integrated parts of structure  16 , such as an internal reflecting surface in the structure, or a reflective filter. Point  14  may be where filter  18  is reflective of a particular wavelength. Filter  18  may allow light  19  to pass through it to optical port  13 . Light  12  may enter optical port  13  and go through a wavelength filter  18 . Filter  18  may be a dichroic filter that reflects one or more wavelengths and transmits others. Filter  18  may be designed to pass light  19  of a second wavelength. All other wavelengths of light  12  are not transmitted through filter  18 . Light  19  of the second wavelength may be detected by a detector  21  and converted into electrical signals. Light  19  may be modulated. Detector  21  along with an electronics module  67  may demodulate such light. Detector  21  may be a photo detector or another kind of device as appropriate for an application of the assembly. Light signals may be sent and received by device  10  simultaneously. On the other hand, components  17  and  21  may both be detectors or sources and receive or send, respectively, various signals simultaneously on different wavelengths of light, or on the same wavelength. Device  17  and/or  21  may both a source and a detector.  
         [0008]    Source  17  and detector  21  may be enclosed within a standard TO can (e.g., TO- 5  or TO- 18 ) as optical components. These components may electronically and packaging-wise have interfaces to standard PCBs for SFP modules. These components may have other forms of packaging. Alternatively, components  17  and  21  may be integral parts of structure  16 . Lenses  22  and  23  for light source  17  and detector  21 , respectively, may be molded plastic parts. The lenses also may be parts integrated into structure  16  or be molded as part of the structure. Lenses  22  and  23  may instead be part of TO can components  17  and  21 , or be situated on or monolithically be a part of the laser and detector chips. Lens  24  at optical port  13  may focus incoming light to a mirror, filter or detector in structure  16 . It may also focus outgoing light to a light waveguide, such as a fiber, at optical port  13 . Lens  24  may have the same structural characteristics as those of lenses  22  and  23 . Lenses  22 ,  23  and  24  may also be use to collimate light.  
         [0009]    Structure  16  may be a molded plastic part, made from a material such as Ultem R , or it may be an injection molded metal part or other metal housing. Structure  16  also may be made from a composite material. The TO can optical components  17  and  21  may be attached to the plastic or metal structure  16  with an epoxy or laser welding, respectively. These components are alignment tolerant. Metal rings may be attached to a plastic structure  16  for laser welding metal components to it. Dichroic filter  18  or mirror may be placed in a molded indent formed within plastic or metal structure  16  and glued in place or it may be inserted and held in place by compression. A molded groove in structure  16  may provide appropriate alignment of dichroic filter  18 . Alternatively, structure  16  may be composed of two pieces glued together, one or both of which may have dichroic reflectors deposited on their surfaces.  
         [0010]    [0010]FIG. 2 shows an optical assembly  20 . Structure  16  of assembly  20  is like that of assembly  10 . Instead of a filter  18 , a reflector  25 , such as dichroic mirror, may be used. Light  26  may enter and strike reflector  25 . Reflector  25  may reflect only light  28  of a third wavelength, as an illustrative example, from light  26 , which has other wavelengths as well, entering optical port  13 . The remaining light with the other wavelengths may pass through reflector  25 . Light  28  may be reflected by surface  15  of structure  16  to an optical component  29 . Component  29  may be a photo detector that detects light  28 , such as a charge coupled device (CCD), a photodiode, a resonant cavity photo detector (RCPD), an avalanche photodiode (APD), or another kind of light detector. Optical component  31  may emit light  32  having a fourth wavelength. Some of light  32  may go through dichroic mirror  25 , including light having the fourth wavelength. Component  31  may be a laser, vertical cavity surface emitting laser (VCSEL), a light emitting diode (LED), or another kind of light emitter. Light signals  32  and  28  may be sent and received by the components of device  20 , simultaneously. On the other hand, components  29  and  31  may both be detectors or sources that receive or send simultaneously various light signals having different wavelengths.  
         [0011]    Device  20  may also have an optical fiber ferrule receptacle  33  for optical connection and for physically securing an optical fiber  34  to structure  16 . Fiber ferrule receptacle  33  may be molded in with metal, plastic or ceramic, or be aligned and attached as a subassembly of structure  16 . Active two-axis alignment capabilities may be provided by receptacle  33  for optically connecting fiber  34  or another light conveying mechanism to device  20 . Another kind of receptacle may be implemented for optically and physically connecting other kinds of light conveying mechanisms to structure  16 .  
         [0012]    [0012]FIG. 3 shows a bidirectional optical device  30  having a multitude of optical components, such as just detectors or sources, or a mix of detectors and sources. The number of optical components is arbitrary, and may be determined by the application of device  30 . Device  30  reveals five optical components  41 ,  42 ,  43 ,  44  and  45 , as an illustrative example of a structure  35 . Light  36  may arrive through port  13  and light  37  may exit port  13 . Light  36  received may have a multitude of wavelengths, each wavelength having communication signals different from those of other wavelengths. Similarly, light  37  sent out may have a multitude of wavelengths, each wavelength having communication signals different from those of other wavelengths. Light  36  and light  37  may be conveyed to and from optical components  41 ,  42 ,  43 ,  44  and  45  by an optical mechanism  38 . Mechanism  38  may be a light waveguide, an optical fiber, a series of mirrors, or other items to accomplish the conveyance of light  36  and  37  to and from the optical components. Or mechanism  38  might not be utilized. Lenses  24  and  68  may be used to focus or collimate light as appropriate. The lenses may be an integral part of structure  35 . Light  36  and light  37  to or from optical components  41 ,  42 ,  43 ,  44  and  45  may go through filters, for example, dichroic filters  46 ,  47 ,  48 ,  49  and  50 , respectively. In other words, if each optical component has a wavelength different from the other optical components, there may be a filter of that wavelength associated with the respective component. For instance, optical component  41  may send or receive light signals if a first wavelength or bandwidth; optical component  42  may send or receive light signals of a second wavelength or bandwidth; optical component  43  may send or receive light signals of a third wavelength or bandwidth; optical component  44  may send or receive light signals of a fourth wavelength or bandwidth; and optical component  45  may send or receive light signals of a fifth wavelength or bandwidth. Similarly, filter  46  may transmit or pass light signals only of a first wavelength or bandwidth; filter  47  may transmit light only of a second wavelength or bandwidth; filter  48  may transmit light of only a third wavelength or bandwidth; filter  49  may transmit light of only a fourth wavelength or bandwidth; and filter  50  may transmit light of only a fifth wavelength or bandwidth. All of optical components  41 ,  42 ,  43 ,  44  and  45  may send light signals  37  and/or receive light signals  36  at the same time.  
         [0013]    Filters  46 ,  47 ,  48 ,  49  and  50  may be replaced with, for example, dichroic reflectors or other wavelength or bandwidth discriminating mechanisms. With such replacements, the optics may be adjusted for conveying light signals  36  and  37  to and from optical components  41 ,  42 ,  43 ,  44  and  45 .  
         [0014]    Structure  35  may be made from molded plastic, for example, Ultem R , metal, composite materials or other suitable materials. Structure  35  may have similar features as those of structures  10  and  20  in FIGS. 1 and 2.  
         [0015]    One application of use of the invention as described in this specification is shown in FIG. 4. An electrical signal  51  may enter input  52  of a transceiver  53  where signal  51  is converted to an optical signal  54 . Optical signal  54  is output through an optical port  57  by transceiver  54 . Optical signal  54  traverses through an optical fiber  55  to an optical port  58  of transceiver  56 . Transceiver  56  converts optical signal  54  to an electrical signal  59  which comes out of transceiver  56  on an output  60 . In the other direction, an electrical signal  61  may enter input  62  of transceiver  56  where signal  61  is converted to an optical signal  63 . Optical signal  63  is output through optical port  58  of transceiver  56  to optical fiber  55 . Optical signal traverses through optical fiber  55  and enters transceiver  53  through optical port  57 . Optical signal  63  is converted to an electrical signal  65  by transceiver  53 . Signal  65  comes from transceiver  53  at output  64 . The signals may be sent in both directions simultaneously. The optical signals may be of the same wavelength or different wavelengths. Wavelength-separation elements  69  may be introduced mid-span in optical fiber  55 , such that, for example, transceiver  53  may send an optical signal  54  to transceiver  56 , but an optical signal  63  from transceiver  56  may be directed to a third transceiver  70  in a different location. The transceivers or sets of transceivers may be utilized in communications, controls and other applications.  
         [0016]    Although the invention has been described with respect to at least one illustrative embodiment, many variations and modifications will become apparent to those skilled in the art upon reading the present specification. It is therefore the intention that the appended claims be interpreted as broadly as possible in view of the prior art to include all such variations and modifications.