Finisar Corporation

Yalan Mao

Wei W Wang

Ping Peter Xie

R Brad Bettman

Nadim I Maluf

Simon Yuanxiang Wu

Kevin Dapeng Zhang

Haisheng Rong

Simon Yuanxinag Wu

Brad R Bettman

An optical device that can be used in a range of telecommunications applications including optical multiplexers/demultiplexers and optical routers. The optical device includes an optical processing loop which allows multi-stage performance characteristics to be achieved with a single physical filtration stage. Optical processing on the first leg and second legs of the loop is asymmetrical thereby improving the integrity of the optical signals by effecting complementary chromatic dispersion on the first and second legs. In an embodiment of the invention the optical device includes a fundamental filter cell, a retro reflector and a splitter/combiner. The fundamental filter cell filters optical signals propagating on each of two legs of an optical loop which intersects the fundamental filter cell. The fundamental filter cell operates as a full waveplate to the odd set of channels and a half waveplate to the even set of channels on a selected one of the two legs and as a half waveplate to the odd set of channels and a full waveplate to the even set of channels on a remaining one of the two legs. The retro reflector optically couples with the fundamental filter cell to reflect the optical signals from one of the two legs to an other of the two legs to form the optical loop. The splitter/combiner optically couples between the fundamental filter cell and the retro reflector to split or combine the odd set of channels and the even set of channels depending on the propagation direction of the optical signals along the optical loop.

Method and apparatus for an optical multiplexer and demultiplexer with an optical processing loop

Methods for combining or splitting optical signals that include an odd channel set an even channel set. The methods of combining or splitting are performed by subjecting the odd and even channel sets to a first filter that applies phase retardations corresponding with odd integer multiples of half a wavelength for each center wavelength associated with a selected one of the odd and even set of channels and with integer multiples of a full wavelength of each center wavelength associated with a remaining one of the odd set and the even set. The channel sets are then subjected to a second filter that applies phase retardations that are complementary to those experienced by the odd and even set of channels in the first filter. This complementary filtration has the effect of reducing dispersion. These methods may be used in optical devices applicable to a range of telecommunications applications, including optical multiplexers/demultiplexers and optical routers.

Optical filter for wavelength division multipled optical signals

An optical device that can be used in a range of telecommunications applications including optical multiplexers/demultiplexers and optical routers. The optical device splits and combines optical signals of frequency division multiplexed optical communication channels that are evenly spaced apart in frequency from one another. The optical device includes a first filter and a second filter. The first filter splits and combines odd and even channels depending on the propagation direction of the optical signal. The first filter exhibits complementary phase retardations corresponding with odd integer multiples of half a wavelength for each center wavelength associated with a selected one of the odd and even set of channels and with integer multiples of a full wavelength of each center wavelength associated with a remaining one of the odd set and the even set. The second filter couples with the first filter to filter the odd and even sets of channels with phase retardations complementary to those experienced by the odd and even set of channels in the first filter. This complementary filtration has the effect of reducing dispersion in the device.

The present invention provides optical filters that can be used in a range of telecommunications applications including optical multiplexers/demultiplexers, optical routers, and optical gain scalers. The optical filter is modular, using two or more couplers with a pair of delay paths between each pair of couplers in a sequence to generate a range of optical filter functions. The desired filter profile/function is obtained by proper selection of the coupling ratio for each coupler and by the length of each pair of delay paths. The couplers may be implemented as polarization or intensity beam splitters positioned along the optical path. Each coupler couples in controllable amounts, one or two inputs with the corresponding pair of delay paths. Where a coupler is implemented as a polarization beam splitter, the coupling is accomplished by input to the coupler of polarized light and by the subsequent separation of orthogonal &ldquo;P&rdquo; and &ldquo;S&rdquo; components of that light onto corresponding ones of the pair of delay paths. Where coupling is implemented with an intensity beam splitter, the coupling is accomplished by input of light with the percentage of reflection and transmission of the light determining the coupling ratio or percentage of the light input onto corresponding ones of the pair of delay paths. The pair of delay paths includes in an embodiment of the invention, passive thermal stabilization. The passive thermal stabilization of the filter(s) is accomplished by a plurality of optical elements positioned in and defining the optical path length of each member of the pair of paths. These optical elements are designed so that the optical path length difference between the pair of delay paths remains substantially invariant across a range of temperatures.

Method and apparatus for an optical filter

An optical device that can be used in a range of telecommunications applications including optical multiplexers/demultiplexers and optical routers. The optical device splits and combines optical signals of frequency division multiplexed optical communication channels which are evenly spaced apart in frequency from one another. The optical device includes a first filter and a second filter. The first filter splits and combines odd and even channels depending on the propagation direction of the optical signal. The first filter exhibits complementary phase retardations corresponding with odd integer multiples of half a wavelength for each center wavelength associated with a selected one of the odd and even set of channels and with integer multiples of a full wavelength for each center wavelength associated with a remaining one of the odd set and the even set. The second filter couples with the first filter to filter the odd and even sets of channels with phase retardations complementary to those experienced by the odd and even set of channels in the first filter. This complementary filtration has the effect of reducing dispersion in the device.

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Cupertino, CA, United States of America

Yalan Mao