Abstract: An optical amplifier includes an optical feedback resonant laser cavity (OFRC) including a power dependent loss element (PDLE) having the characteristic that as the incident laser power on the PDLE increases the cavity loss decreases. The OFRC with the PDLE provides optical gain control or optical power control for a WDM amplifier or a single channel power equalization amplifier (PEA), respectively. A 1×N×N WADM node incorporating more than one of these amplifiers, at least some of which commonly share a pump source, and a method for controlling a transient power change in a single channel optical amplifier or reducing a DC gain error in a WDM optical amplifier that are subject to dynamically variable operating conditions at an input of the amplifier, are also disclosed.

Abstract: A method of operating an optical amplifier for improved gain and pump-to-signal conversion efficiency in a long wavelength spectral region (L-band) of the emission spectrum of a rare earth doped gain medium having a known pump absorption band involves the steps of providing an optical signal to the amplifier having a large-signal input power; and providing pumping light to the amplifier having a wavelength that is different from a center wavelength of the known pump absorption band for amplifying the optical signal. Signal gain and improved pump-to-signal conversion efficiency was demonstrated for an erbium L-band signal by detuning the pump between about ±0-30 nm on either side of the pump band center wavelength of 979-980 nm. An optical amplifier employing the described method is also disclosed.

Abstract: A fiber optic device for use in fiber optic transmission systems and components thereof includes a pass-through fiber and one or more lengths of circulating fiber connected to the pass-through fiber by respective optical switches for selectively routing an optical signal through the circulating fiber lengths as it propagates along the pass-through fiber. The circulating fiber lengths are either dispersion compensating fibers or fibers doped with a substance that will amplify or absorb the optical signal in the respective presence or absence of a pump signal. The invention thus allows various amounts of dispersion or gain (absorption) to be selectively switched into or out of use depending upon requirements at the time. For example, an amplifying component could serve as a pre- or power- or in-line amplifier device depending on the lesser or greater amount of gain fiber elected by switching.

Abstract: A package for a high power semiconductor laser comprising a hermetically sealed container filled with a dry gaseous medium containing oxygen. The presence of oxygen in the laser atmosphere is counter to standard practice in the art which teaches the use of an atmosphere of a dry inert gas. The package also includes a getter for organic impurities, e.g., a getter composed of a porous silica or a zeolite. The hydrogen content of the materials used to form the package are reduced by baking at an elevated temperature for an extended period of time, e.g., at 150.degree. C. for 200 hours.

Abstract: A package for a high power semiconductor laser comprising a hermetically sealed container filled with a dry gaseous medium containing oxygen. The presence of oxygen in the laser atmosphere is counter to standard practice in the art which teaches the use of an atmosphere of a dry inert gas. The package also includes a getter for organic impurities, e.g., a getter composed of a porous silica or a zeolite. The hydrogen content of the materials used to form the package are reduced by baking at an elevated temperature for an extended period of time, e.g., at 150.degree. C. for 200 hours.

Abstract: Disclosed is a family of dispersion compensating optical fibers that are adapted for use with conventional single-mode transmission fibers that are optimized for zero dispersion operation at a wavelength in the range from 1290 nm to 1330 nm to form a transmission link suitable for low dispersion operation in the 1520-1565 nm wavelength window. The dispersion compensating fibers are capable of providing a dispersion more negative than -20 ps/nm-km and attenuation less than 1 dB/km at wavelengths in the 1520-1565 nm region. Certain of the dispersion compensating fibers also exhibit a dispersion versus wavelength relationship having a negative slope in the 1520-1565 nm region, to compensate for the dispersion versus wavelength slope of the transmission fiber. The dispersion compensating fiber can be advantageously combined with a fiber amplifier to form a compensator that is adapted to overcome attenuation introduced into the system by the dispersion compensating fiber.

Abstract: The use of a doped optical fiber amplifier enables the transmission of multi-channel AM-VSB television signals. An Erbium doped fiber amplifier is disclosed. The amplifier is also useful for reducing second order distortion products produced in an amplitude modulated subcarrier optical communication system. The amplifier may be used in a tree and branch structure optical fiber television network.

Abstract: The use of a doped optical fiber amplifier enables the transmission of multi-channel AM-VSB television signals. An Erbium doped fiber amplifier is disclosed. The amplifier is also useful for reducing second order distortion products produced in an amplitude modulated subcarrier optical communication system. The amplifier may be used in a tree and branch structure optical fiber television network.

Abstract: This invention relates to thallium germanate, tellurite, and antimonite glasses possessing high optical nonlinearity, as well as good visible and infrared transmission, making them suitable materials for the fabrication of active optical devices.

Abstract: This invention relates to thallium tellurite glasses possessing a high Verdet constant and high optical nonlinearity, as well as good visible and infrared transmission, making them suitable materials for the fabrication of active optical devices. The glasses consist essentially, expressed in terms of cation percent, of 5-74.5% TeO.sub.2, 0.5-20% SiO.sub.2, 4-50% TlO.sub.0.5, and 0-71% PbO, wherein PbO+T10.sub.0.5.gtoreq.25 %, TeO.sub.2 +SiO.sub.2 .gtoreq.25%, and TeO.sub.2 +SiO.sub.2 +TlO.sub.0.5 +PbO constitutes at least 65% of the total composition.

Abstract: Disclosed is a fiber amplifier system including a gain fiber having a single-mode core doped with active dopant ions capable of producing stimulated emission of light at wavelength .lambda..sub.s when pumped with light of wavelength .lambda..sub.p. Spliced to the gain fiber is a light-attenuating fiber having a core containing a dopant that attenuates light of wavelength .lambda..sub.p but not .lambda..sub.s. The amplifier is conventionally employed in a system including an incoming telecommunication fiber for introducing light of wavelength .lambda..sub.s into an end of the gain fiber, the amplified signal being connected to an outgoing telecommunication fiber. The system further includes a pump source for introducing light of wavelength .lambda..sub.p into an end of the gain fiber. Elements of the system can be arranged for forward pumping, counter pumping and dual ended pumping.

Abstract: The use of a doped optical fiber amplifier enables the transmission of multi-channel AM-VSB television signals. An Erbium doped fiber amplifier is disclosed. The amplifier is also useful for reducing second order distortion products produced in an amplitude modulated subcarrier optical communication system. The amplifier may be used in a tree and branch structure optical fiber television network.

Abstract: Disclosed is a fiber amplifier system in which a gain fiber is operatively combined with a fiber optic coupler having first and second coupler optical fibers. The coupler fibers are fused together along a portion of their lengths to form a wavelength dependent coupling region whereby most of the light power of a wavelength .lambda..sub.s couples between them, and most of the light power of a wavelength .lambda..sub.p that is introduced into the first fiber remains in it. The mode field diameter of the first coupler fiber is substantially matched to that of the gain fiber and is smaller than that of the second coupler fiber. One end of the first coupler fiber is spliced to the gain fiber. A transmission fiber is spliced to the second coupler fiber, and a laser diode introduces pumping light of wavelength .lambda..sub.p to the first coupler fiber. The fiber optic coupler preferably includes an elongated body of matrix glass through which the first and second coupler fibers extend.

Abstract: Disclosed is a fiber amplifier system including a gain fiber having a single-mode core containing dopant ions capable of producing stimulated emission of light at wavelength .lambda..sub.s when pumped with light of wavelength .lambda..sub.p. Absorbing ion filtering means is operatively associated with the gain fiber to alter the gain curve. If the absorbing ions are the same as the gain ions of the gain fiber, the system further includes means for preventing pump light from exciting the gain ions of the filtering means. The excitation prevention means may take the form of means for attenuating pump light. If the absorbing ions are different from the dopant ions of the gain fiber, such absorbing ions can be subjected to light at wavelength .alpha..sub.p, but they will remain unexcited. Such absorbing ions can be used to co-dope the gain fiber, or they can be incorporated into the core of a fiber that is in series with the gain fiber.

Abstract: An optical signal amplifier with a waveguide path integrated into a glass body that is doped with optically active material. The signal to be amplified is transmitted through the waveguide and the pump power is coupled into the waveguide at one end. The waveguide comprises closely spaced adjacent guide lengths in the form of a spiral, zigzag paths between mirrors, or parallel paths with connecting semicircles at alternating ends of succeeding pairs of paths.

Abstract: This invention is drawn to heavy metal oxide glasses exhibiting high nonlinear susceptibility and infrared transmission consisting essentially, in weight percent, of 42-48% PbO, 33-44% Bi.sub.2 O.sub.3, 10-15% Ga.sub.2 O.sub.3, and up to 15% total of at least one member of the group consisting of up to 5% SiO.sub.2 and/or GeO.sub.2 and up to 15% Tl.sub.2 O. This invention also comprehends the fabrication of light guiding fibers from those glasses.

Abstract: This invention relates to thallium germanate, tellurite, and antimonite glasses possessing high optical nonlinearity, as well as good visible and infrared transmission, making them suitable materials for the fabrication of active optical devices.

Abstract: The disclosed fiber optic filter structure includes an optical fiber having a single-mode core surrounded by cladding material, and at least one light-attenuating light path in the cladding material uniformly spaced from the single-mode core. The propagation constants of the single-mode core and the light path are different at wavelengths except for at least one wavelength .lambda..sub.4. The spacing between the single-mode core and the light path are sufficiently small that light within a first band of wavelengths centered around .lambda..sub.f couples between the single-mode core and the light path. At least a portion of the light within the first band of wavelengths is absorbed in the light path. In that embodiment in which the single-mode core is a fiber amplifier gain core, the filtering function of the light path modifies the fiber amplifier gain spectrum.

Abstract: Disclosed is a fiber amplifier system including a gain fiber having a single-mode core containing dopant ions capable of producing stimulated emission of light at wavelength ?s when pumped with light of wavelength ?p. Absorbing ion filtering means is operatively associated with the gain fiber to alter the gain curve. If the absorbing ions are the same as the gain ions of the gain fiber, the system further includes means for preventing pump light from exciting the gain ions of the filtering means. The excitation prevention means may take the form of means for attenuating pump light. If the absorbing ions are different from the dopant ions of the gain fiber, such absorbing ions can be subjected to light at wavelength ?p, but they will remain unexcited. Such absorbing ions can be used to co-dope the gain fiber, or they can be incorporated into the core of a fiber that is in series with the gain fiber.