Onetta, Inc.

Chia-Chi Wang

Yongan Wu

James W Sulhoff

Jun Ye

Paul Francis Wysocki

James Patrick Koonmen

Yan Sun

Optical amplifiers and optical network equipment are provided that have optical gain stages for amplifying optical signals on a fiber-optic communications link. The optical gain stages may be based on optically pumped fiber such as rare-earth-doped fiber. The fiber may be optically pumped using laser diode pumps. A control unit may be provided in the amplifiers or other equipment to control the laser diode pumps. Optical monitors may be used to measure the optical signals in the amplifiers or other equipment. The pump powers of the laser diode pumps may be adjusted in real time by the control unit based on the measured optical signals to suppress gain transients due to input power fluctuations on the link. To minimize the impact of pump-induced noise, the control unit may avoid operating the laser diodes at powers at which the laser diodes are most susceptible to mode partition noise.

Optical amplifiers with stable output power under low input power conditions

Optical amplifiers and other optical network equipment for handling optical data signals in fiber-optic communications links are provided. Optical fiber that is pumped by laser diode pumps may be used to provide optical gain. A circulator may be used in an amplifier to direct the optical data signals through a double-pass portion of the amplifier. A reflector at the end of the double-pass portion of the amplifier may direct forward-propagating optical data signals from the circulator in the backwards direction. Optical components such as spectral filters, and attenuators, gain stages, access ports, and other components may be located in the double-pass portion. A control unit may be used to suppress gain transients in the double-pass portion.

Double-pass optical amplifiers and optical network equipment

Optical amplifiers and methods for manufacturing optical amplifiers are provided that allow amplifiers to be fabricated to match design expectations. Optical amplifiers may be manufactured by assembling passive optical components in the amplifier before assembling active optical components such as doped fiber coils. Passive losses may then be characterized and used to calculate the lengths of the fibers that should be used in the amplifier gain stages. Following corrections to the nominal doped-fiber lengths based on the measured passive losses, the passive and active components of the amplifier may be assembled and characterized. Final corrections may be made to the amplifier assembly based on these characterizations. For example, the lengths of one or more of the doped fibers may be adjusted. If desired, such length adjustments may be made to fiber coils in the mid-stage portion of the amplifier, so that the impact on the operating characteristics of the amplifier are minimized.

Optical amplifiers and methods for manufacturing optical amplifiers

Optical amplifiers with variable optical attenuators that are adjusted using a sublinear control scheme are provided. Instead of increasing the attenuation of the optical attenuator by Y dBs for each desired Y dBs in decreased optical amplifier gain, the attenuation of the variable optical attenuator is increased by less than Y dBs. This sublinear control scheme improves the noise figure performance of the optical amplifier at the expense of increased gain ripple. The overall performance of the optical amplifier may be improved, particularly in conditions in which the attenuations produced by the variable optical attenuator are relatively large.

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Hillsborough, NJ, United States of America

Chia-Chi Wang