System and method for bi-directional optical communication

#The present invention relates generally to the field of communications, and more particularly, to a system and method for optical bi-directional communication.

#Current communications systems and networks are becoming faster and more complex, using any one of number of mediums. Communication using these systems and networks is typically bi-directional in that signals are exchanged between two sources as they communicate for various purposes. More recently, fiber optic networks have been employed as the medium for communications. Typically, the optical fibers themselves may be very small and, consequently, coupling various devices to the optical fibers to create a communications link can be difficult and expensive.

#An additional problem with current optical fiber communications systems is that optical fibers are often used for unidirectional communications. This is due in part to the difficulty of physically transmitting and receiving an optical signal on a single optical fiber that may be, for example, a single micron thick. Unfortunately, this results in the need for two optical fiber links to establish bi-directional communications.

#The invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

#FIG. 1A is a drawing of a bi-directional communications link according to an embodiment of the present invention;

#FIG. 1B is a top view of the bi-directional communications link of FIG. 1A;

#With reference to FIG. 1A, shown is a bi-directional optical link 100 according to an embodiment of the present invention. The bi-directional optical link 100 includes a thin film detector 103, a thin film emitter 106, and a beam turning device 109. The detector 103 and the emitter 106 are disposed on a host substrate 113 as shown. The detector 103 is preferably flat in shape with a thickness that is, for example, relatively small. The detector 103 includes an upper surface 116 oriented to receive incident light 119 from a predetermined direction 123, that is, for example, normal to the upper surface 116. The incident light 119 propagates, for example, from an optical fiber 126 as shown where the optical fiber 126 has a core 129 and a cladding 133. The emitter 106, detector 103, and the beam turning device 109 are thin film devices.

#During operation of the bidirectional optical link 100, the emitter 106 generates a beam of light 136 that is directed toward the turning device 109. The turning device 109 redirects the beam of light 136 toward the predetermined direction 123 as shown. The optical fiber 126 is positioned so as to receive the beam of light 136 and to ensure that the incident light 119 propagates from the optical fiber 126 onto the upper surface 116 of the detector 103. In other words, the optical fiber 126 is positioned so as to face the detector 103 and the turning device 109 from the predetermined direction 123. Both the incident light 119 and the beam of light 136 are modulated accordingly. In this manner, the bi-directional optical link 100 advantageously allows a single optical fiber 126 to be used for bi-directional communications.

#The emitter 106 may be, for example, an edge emitting laser or an edge emitting, light emitting diode (LED), or other suitable light source. The actual component chosen as the emitter depends in part on the capabilities and attributes of the component and the particular application. For example, edge-emitting lasers allow higher speed operation than LED's, but also include higher power consumption. The emitter 106 includes electrical contacts that are bonded to the host substrate 113 using suitable conductive bonding agents such as metals, conductive polymers, conductive epoxies, and other suitable materials known in the art. In particular, the electrical contacts are preferably bonded to counterpart electrical contacts on the host substrate 113, where the circuit that drives the emitter 106 is also located on the host substrate 113. The emitter 106 may be bonded to the host substrate 113 using non-conductive bonding agents as well.