Jds Uniphase Corporation

Yatao Yang

Bo Song Chen

Bo Cai

Ming Liang

Xiaobiao Wang

Xishe Liu

Chang Xiao

Yujian Bao

Fenhong Zhou

Ting Xue

Miaoqing Wang

Yunhui Sun

A compact PD unidirectivity solution for an optical tap monitor, which reduces the overall size of optical tap module, is provided. The solution is to use lensing to separate the light from the input and output fibers, and then add a mask or spacer in front of the monitor PD to prevent any of the light from the output fiber from entering the photodetector package.

Compact tap monitor with a reflection mask

A variable optical attenuator is disclosed, which attenuates a beam of light while preserving its polarization substantially independent of wavelength. The beam of light is attenuated by a filter patterned with a grating of blocking stripes with serrated edges, which partially block and partially transmit the beam of light, respectively. The serrated edges provide for low polarization dependent loss. Along a length of the filter, a mark to space ratio of blocking stripe and aperture widths increases. By a linear translation of the filter along its length attenuation can be varied to a desired value. A stepper motor with lead screw can provide a suitable linear translation to give the filter a latching property.

Variable Optical Attenuator

The tunable add/drop multiplexer including a tiltable mirror, a fixed thin film filter, and first and second retro-reflector elements for redirecting express channels back out an input/output port and for redirecting drop channels back out an add/drop port, respectively.

Tunable optical add/drop multiplexer

The invention relates to compensating for the wavelength dependent loss (WDL) in a variable optical attenuator (VOA) system by using a chromatic dispersion wedge, which is inserted between the mirror and the lens. Different wavelength components, e.g. shorter blue and longer red wavelengths, are redirected at different angles by the chromatic dispersion wedge and now arrive at the output fiber at different positions. Thus the smaller mode field diameter (MFD) or mode spot size of the blue light, overlaps more of the core of the output fiber by being closer thereto and now has less insertion loss (IL) as compared to a VOA without WDL compensator.

Variable optical attenuator with wavelength dependent loss compensation

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Plano, TX, United States of America

Yatao Yang