Abstract: The present invention provides for an improved package for a laser diode. The package has portions of its inner surfaces covered with a non-reflecting material, such as simple black paint, non-reflective metals or specific anti-reflection coatings. Such non-reflecting materials surprisingly enhances the performance of packaged laser diodes used as pumping lasers for fiber amplifiers, for example.

Abstract: An improved polarization beam splitter formed by a collimator and two similarly shaped, birefringent crystal prisms is provided. The light from the collimator is incident upon the first face of the first birefringent crystal prism which also has second and third faces. The collimated light is incident upon the second face at an angle .phi. with respect to a line normal to the second face so that light polarized perpendicular to a plane of incidence upon the second face is reflected toward the third face and light polarized in the plane of incidence is refracted at the second face. The second birefringent crystal prism has a second face parallel to, and in close proximity with, the second face of the first birefringent prism so that light refracted at the second face of said first prism is refracted at the second face of the second prism and into the second prism.

Abstract: A high performance optical circulator is formed by a polarization beam splitter and optical port assemblies. The polarization beam splitter is formed by two prisms with an interface between the prisms. The interface transmits linearly polarized light directed at the interface in directions responsive to a polarization orientation of linearly polarized light. The optical port assemblies are arranged with respect to the polarization beam splitter so that light from one port assembly is transmitted by the polarization beam splitter interface to another optical port assembly and light from this optical port assembly is transmitted by the beam splitter interface to still another optical port assembly.

Abstract: A laser diode package assembly is described. Besides a laser diode, the package assembly has an optical fiber section having an end located to receive the light output from the laser diode. The optical fiber section also has a fiber grating designed to operate as a bandpass filter. The fiber grating inside the package assembly not only narrows the output wavelength from the laser diode, but also increases the lifetime of the laser diode.

Abstract: An improved polarization beam splitter formed by a collimator and two similarly shaped, birefringent crystal prisms is provided. The light from the collimator is incident upon the first face of the first birefringent crystal prism which also has second and third faces. The collimated light is incident upon the second face at an angle .phi. with respect to a line normal to the second face so that light polarized perpendicular to a plane of incidence upon the second face is reflected toward the third face and light polarized in the plane of incidence is refracted at the second face. The second birefringent crystal prism has a second face parallel to, and in close proximity with, the second face of the first birefringent prism so that light refracted at the second face of said first prism is refracted at the second face of the second prism and into the second prism.

Abstract: Assemblies having a first optical circulator, a pumping laser, a rare-earth doped fiber and a first coupler are described. The first coupler has a first fiber connected to the optical circulator, a second fiber connected to said pumping laser, and a third fiber connected to one end of the rare-earth doped fiber which is operated as a fiber amplifier. The coupler blocks the pumping laser light from the first fiber and reflects the light into the third fiber. The coupler further transmits the input signals from the first fiber into the third fiber. This arrangement allows the rare-earth doped fiber to amplify the input signals from the energy of the pumping laser light. By changing the elements connected to the second end of the rare-earth doped fiber, optical fiber amplifier assemblies in which the message signals are amplified by passing through the rare-earth doped fiber twice, by pumping the rare-earth doped fiber with two pumping lasers, or both, are provided for.

Abstract: A compact optical circulator which can be expanded into a large number of optical ports is provided. For each port, the circulator has an optical port assembly which has an end of an optical fiber, a collimator subassembly and a birefringent crystal. The collimator subassembly collimates light from the optical fiber end into a beam of collimated light and focusses a beam of collimated light to the optical fiber end in a reverse direction. The birefringent crystal is dimensioned and arranged with respect to the collimator subassembly to split the collimated light beam from the collimator subassembly into two parallel beams of light linearly polarized perpendicularly to each other, and to combine parallel beams of light linearly polarized perpendicularly to each other in the reverse direction into a beam of collimated light toward the collimator subassembly.

Abstract: A high performance optical circulator is formed by a polarization beam splitter and optical port assemblies. The polarization beam splitter is formed by two prisms with an interface between the prisms. The interface transmits linearly polarized light directed at the interface in directions responsive to a polarization orientation of linearly polarized light. The optical port assemblies are arranged with respect to the polarization beam splitter so that light from one port assembly is transmitted by the polarization beam splitter interface to another optical port assembly and light from this optical port assembly is transmitted by the beam splitter interface to still another optical port assembly.

Abstract: A waveguide pack for transmission of information that includes a length of a dielectric waveguide wound into a free-standing coil with an inner diameter of less than three inches and coated with a binder suited to maintaining the waveguide in the coil, and a method for preparing the pack.