Abstract: The dual wavelength pumping scheme controls the relative population of the termination state vis-a-vis the metastable state. Praseodymium doped chalcogenide glass and a variety of thulium doped glasses are described as examples. The relative pump powers or wavelengths may be adjusted to control the gain spectrum of the amplifier, making the amplifier useful in a variety of different optical systems including wavelength division multiplexed systems.

Abstract: A wavelength division multiplexer including a channel combining component receiving optical signals transmitted through a plurality of optical channels. The channels are defined by successively different light wavelength bands at intervals ranging between a first channel having the lowest wavelength band to a last channel having the highest wavelength band. The channel combining component combines at least one channel having a wavelength band intermediate the lowest wavelength band and the highest wavelength band with channels having the lowest and the highest wavelength bands. The channel combining component includes an edge filter. This edge filter combines optical signals in the highest and lowest wavelength bands, but not in the intermediate wavelength band. (The highest and said lowest wavelength bands are situated respectively above and below the intermediate wavelength band.) The edge filter provides the combined optical signals to the channel combining component.

Abstract: Negative thermal expansion materials, methods of preparation and uses therefor are disclosed. The materials are useful for negative thermal expansion substrates, such as those used for optical fiber gratings.

Abstract: The method and apparatus of the present invention achieves the trimming and, therefore, tuning of fiber optic devices by, in on embodiment, precisely heating a small area of a fiber to allow its elongation when mounted under tension in its package. By pulsing a source of heat in precise amounts, the elongation can be precisely controlled within 1 picometer precision over a tuning range of about 200 picometers. In another embodiment with fibers having core dopants which can be diffused, the optical length of an optical fiber can be trimmed with nanometer precision. By employing a controlled source of localized energy applied to the optical fiber, real time trimming can be achieved in both systems by injecting a broad band source of energy at the input of the device and coupling a spectral analyzer at its output to monitor the frequency characteristic of the optical device during trimming.

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: Devices are made comprising a tin-phosphorous oxyfluoride glass, which has been exposed to light, preferably shorter in wavelength than the absorption edge of the glass, to change the refractive index change of the glass. The glasses can be used to form planar and fiber devices, including core/clad structures for guiding light.

Abstract: Optical gratings having a range of possible Bragg wavelengths can be produced using a single phase mask by exposing the mask to a non-collimated spatially filtered beam of light. A spatial filter removes high spatial frequency components from the beam, and a focusing system directs the filtered beam to a phase mask. A rate at which the beam is focused and a spacing between the phase mask and a photo-sensitive waveguide are varied to produce gratings in the waveguide having a range of possible periods.

Abstract: An athernal optical device and a method for producing the device, such as an athermal optical fiber reflective grating, are described. The athermal optical fiber reflective grating device comprises a negative expansion substrate, an optical fiber mounted on the substrate surface, and a grating defined in the optical fiber. The method for producing the athermal optical fiber reflective grating device comprises providing a negative expansion substrate, mounting an optical fiber with at least one reflective grating defined therein onto the substrate upper surface, and affixing the optical fiber to the substrate at at least two spaced apart locations.

Abstract: Athermalized optical waveguide devices and methods of making the athermalized devices are described. Boron is incorporated into the composition of the optical waveguides in order to athermalize the waveguides by reducing spectral shifts caused by changes in temperature. The invention includes the utilization of boron dopants in the core and cladding of optical waveguide devices such as Mach-Zehnder coupler devices and long period fiber gratings.

Abstract: Negative thermal expansion materials, methods of preparation and uses therefor are disclosed. The materials are useful for negative thermal expansion substrates, such as those used for optical fiber gratings.

Abstract: The variables and parameters previously understood to affect the gain spectrum of an optical amplifier 13 were: (1) the wavelengths to be amplified; (2) the input power levels at those wavelengths; (3) the characteristics of the amplifying medium 20; (4) the insertion loss spectra of the amplifier's components, including any filter(s) used for gain flattening; (5) the pump band chosen to pump the amplifying medium 20; and (6) the total amount of pump power supplied in the chosen pump band. An additional fundamental variable has been identified which can be used to control the gain spectrum of an optical amplifier 13, namely, the center wavelength of the spectrum of the pump's output power within the chosen pump band. Methods and apparatus for using this variable for this purpose are disclosed.For example a, transmission system is disclosed having a transmitter 11 and a receiver 10 connected by an optical fiber 12.

Abstract: A multichannel fiber optic communication network incorporates multichannel fiber optical amplifiers having different functions but designed to use substantially identical gain flattening filters. This is achieved by designing the amplifiers to have total insertion losses such that their respective internal gains (internal gain=net gain+total insertion loss) are substantially the same, most preferably within 1 dB.

Abstract: An optical device, and a method of producing the device, are disclosed. The device comprises a substrate and an optical waveguide component affixed to the substrate with a glass frit fusion seal formed and locked within a recessed void in the substrate, the glass frit fusion seal being the fused product of a low melting glass frit. The recessed void in the substrate includes a region for receiving the optical waveguide component and an intersecting region that secures the placement of the glass frit fusion seal. The optical waveguide component is affixed to the substrate in order to control temperature varying optical properties of the component.

Abstract: A multi-amplification path optical amplifier including a first amplification path for propagating and amplifying a first in-band optical communication signal, including a spectrally selective filter for substantially blocking the propagation and amplification of an out-of-band optical communication signal along the first amplification path, and a second amplification path for propagating and amplifying a second in-band optical communication signal, including a spectrally selective filter for substantially blocking the propagation and amplification of an out-of-band optical communication signal along the second amplification path, wherein the location of the spectrally selective filters in each respective amplification path is selected so that a target noise figure performance and a target output power performance can be obtained from the device. The spectrally selective insertion losses suppress crosstalk or optical leakage that gives rise to multipath interference, return loss, and self oscillation.