Abstract: The optical receiver has a photodiode (10) which is reverse biased by a voltage supply (14). The voltage supply provides a variable bias voltage determined by a control unit (16) and the photodiode is matched to the load (22) by an impedance matching circuit (12). The photodiode exhibits large capacitance changes over a range of bias voltages and may be implemented using a Schottky barrier or P.sup.+ N photodiode. By changing the bias voltage, the photodiode capacitance changes to vary the tuned frequency of the receiver. The matching circuit cancels the reactive component of the photodiode impedance and matches the resistive component to the load. The photodiode may have a doping profile in which an intrinsic or lightly doped region of width greater than the average photon penetration depth is located next to the junction. After the intrinsic region, the doping profile may be selected to achieve linear tuning. This doping profile gives linear tuning without sacrificing photodiode conversion efficiency.

Abstract: An automated computer controlled process optical fiber splicing system 11 which yields consistent, high strength, low loss, high quality splices. The system of the invention includes a positioning system 17, 21, 29, and 31 for moving at least two optical fiber ends 15 and 19 into relative alignment at a junction 23. A high intensity beam of energy 37 is directed at the junction 23 of the fibers to achieve the high temperatures required for fusing the ends thereof. The focus of the beam 37 is adjusted to control the temperature profile of the energy applied to the junction 23.

Abstract: A long-range optical fiber communication link overcoming certain constraints on signal transmission range imposed by fiber-induced loss is disclosed herein. A first embodiment of the communication link (10) of the present invention includes an optical fiber (16) having a first and a second end wherein the attenuation of optical energy passing therethrough at wavelengths included within a transmission window is substantially minimized. The inventive link (10) further includes a first arrangement (22) and (36) for launching a first optical carrier of a first wavelength onto the first end of the fiber (16). Provision is made within the launching arrangement (22) and (36) for impressing a first modulating signal spanning a first frequency spectrum upon the first carrier. The first embodiment also includes a second arrangement (26) and (37) for launching a second optical carrier of a second wavelength onto the second end of the fiber, wherein the second wavelength is included within the transmission window.

Abstract: Two optical fibers are spliced together to form a single spliced optical fiber. The spliced region is uncontaminated by impurities, and has substantially no loss of optical transmission or mechanical strength as compared to the other regions of the fibers. Splicing is accomplished by removal of the buffer coating, if any, cleaving of the fibers to be spliced to form facing splicing surfaces, careful precleaning of the cleaved fibers in the region adjacent the splicing surfaces, aligning the fibers using optical transmission as the alignment criterion, fusing the fibers together by preheating the region to be spliced, fusing the region, postannealing the spliced region, carefully postcleaning the spliced region, and recoating the spliced region with a UV curable polymer buffer material, if desired. The heating of the fibers to accomplish the fusion is desirably accomplished by a laser such as a carbon dioxide laser.

Abstract: The corporate feed network employs light emitting opto-electronic components, such as laser diodes (12), connected together in a string (14) for distributing RF, microwave, MMW, digital signals, and pulse modulated light. Each diode provides two ports or facets which are coupled to optical fibers (16, 18) to connect to an active phased array antenna, for example. The diodes are selected in number and impedance to provide a good wideband impedance match to the RF/microwave/MMW/digital driving source. Multiple series strings of diodes may be employed, connected in parallel for larger corporate feed structures.

Abstract: A single-mode optical fiber to a single-mode optical channel waveguide end-fire coupler. A single fiber held within a capillary tube and positioned by a micropositioner is adjusted for greatest light output and then secured by an epoxy to one end of a channel waveguide. The two elements are then secured in place in a slot in the capillary tube which prevents rotation of the waveguide relative to the single fiber.