At+t Corp.

At&t Bell Laboratories

Tyco Telecommunications (us) Inc.

Subcom, LLC

Gregory M Wolter

Bruce M Nyman

Alexei N Pilipetskii

Maxim A Bolshtyansky

Morten Nissov

Dmitri G Foursa

George T Harvey

David L Favin

Yanjie Chai

Michael A Mills

Techniques for improving gain equalization in C- and L-band ('C+L') erbium-doped fiber amplifier (EDFAs) are provided. For example, the C- and L-band amplification sections of a C+L EDFA may be separated and configured in a parallel arrangement or a serial arrangement. For both the parallel and serial arrangements, the C- and L-band amplification sections may share a common gain flattening filter (GFF) or each amplification section may include and employ a separate GFF. Moreover, in some examples, an “interstage” L-band GFF may be located before or upstream of the L-band amplification section such that the L-band optical signal is gain-equalized or flattened prior to the L-band amplification section amplifying the L-band.

Gain equalization in C+L erbium-doped fiber amplifiers

An apparatus for measuring the noise figure in optical amplifiers employed for large bandwidth applications such as dense wavelength division multiplexing systems. A booster amplifier coupled to a light source increases the average power associated with a plurality of optical channels. A periodic filter is coupled to the booster amplifier to reflect noise between each of the optical channels across the predetermined bandwidth. An amplifier under test is coupled to the periodic filter and the noise figure associated with the amplifier under test is measured.

Method and apparatus for measuring noise figure in optical amplifiers

Polarization dependent loss (PDL) of an optical component is computed in a deterministic method that requires only four measurements, each having a unique input state of polarization.

System and method for measuring polarization dependent loss

Previous efforts to measure polarization dependent loss of optical components have been limited in uncertainty to more than 0.01 dB. This is because the power meter used in a test set contains polarization dependent loss which adversely affects the final readings. It is here disclosed that an unpumped erbium doped fiber can convert a received polarized signal into unpolarized amplified spontaneous emission of a longer wavelength if the fiber is of sufficient length to absorb the received signal. By locating the inventive unpumped erbium doped fiber upstream of the power meter of a test set, the polarized signal to the power meter is coverted to an unpolarized signal and, therefore, the polarization dependent loss of the power meter can not influence the measurement obtained.

Depolarizer using unpumped, doped optical fiber and method using same

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Oakhurst, NJ, United States of America

Gregory M Wolter