Abstract:
Wavelength division multiplexing (WDM) communication systems invariably require good optical filters meeting stringent requirements on their amplitude response, the ideal...Show MoreMetadata
Abstract:
Wavelength division multiplexing (WDM) communication systems invariably require good optical filters meeting stringent requirements on their amplitude response, the ideal being a perfectly rectangular filter. To achieve high bandwidth utilization, the phase response of these filters is of equal importance, with the ideal filter having perfectly linear phase and therefore constant time delay and no dispersion. This aspect of optical filters for WDM systems has not received much attention until very recently. It is the objective of this paper to consider the phase response and resulting dispersion of optical filters in general and their impact on WDM system performance. To this end we use general concepts from linear systems, in particular, minimum and nonminimum phase response and the applicability of Hilbert transforms (also known as Kramers-Kronig relations). We analyze three different classes of optical filters, which are currently being used in WDM systems and compare their performance in terms of their phase response. Finally, we consider possible ways of linearizing the phase response without affecting the amplitude response, in an attempt to approximate the ideal filter and achieve the highest bandwidth utilization.
Published in: IEEE Journal of Quantum Electronics ( Volume: 34, Issue: 8, August 1998)
DOI: 10.1109/3.704327
Citations are not available for this document.
Cites in Patents (13)Patent Links Provided by 1790 Analytics
1.
Sato, Kenji, "Optical module having three or more optically transparent layers"
Inventors:
Sato, Kenji
Abstract:
A light dispersion filter is composed of three or more optically transparent layers each having a value equal to the value of the product of the refractive index and thickness of the optically transparent layer and transmitted light, and a plurality of partially reflective layers arranged alternately with the optically transparent layers and having predetermined reflectivities. Alternatively, a light dispersion filter has a plurality of etalon resonators which are arranged in series such that the value of the product of the refractive index of air and the interval of the etalon resonators is equal to the value of the product of the refractive index and thickness of the optically transparent layers.
Assignee:
NEC CORP
Filing Date:
20 December 2010
Grant Date:
04 June 2013
Patent Classes:
Current U.S. Class:
359589000, 359588000, 359337500, 398081000, 398149000
Current International Class:
G02B0052800000
2.
Sato, Kenji, "OPTICAL MODULE HAVING THREE OR MORE OPTICALLY TRANSPARENT LAYERS"
Inventors:
Sato, Kenji
Abstract:
A light dispersion filter is composed of three or more optically transparent layers each having a value equal to the value of the product of the refractive index and thickness of the optically transparent layer and transmitted light, and a plurality of partially reflective layers arranged alternately with the optically transparent layers and having predetermined reflectivities. Alternatively, a light dispersion filter has a plurality of etalon resonators which are arranged in series such that the value of the product of the refractive index of air and the interval of the etalon resonators is equal to the value of the product of the refractive index and thickness of the optically transparent layers.
Assignee:
NEC CORP
Filing Date:
04 February 2009
Grant Date:
17 May 2011
Patent Classes:
Current U.S. Class:
359589000, 359337500, 359588000, 398081000, 398149000
Current International Class:
G02B0052800
3.
Von Lerber, Tuomo, "ALL OPTICAL SIGNAL PROCESSING METHOD AND DEVICE"
Inventors:
Von Lerber, Tuomo
Abstract:
A device for processing of an optical input signal includes at least a first data signal. A first optical resonator provides a reference signal by optical filtering of the optical input signal. The first optical resonator is matched with a predetermined reference wavelength of the first data signal. A second optical resonator provides a sideband signal by optical filtering of the optical input signal. The second optical resonator is non-matched with the predetermined reference wavelength of the first data signal. An optical combiner combines the sideband signal with the reference signal to form an optical output signal.
Assignee:
LUXDYNE OY
Filing Date:
07 September 2005
Grant Date:
11 August 2009
Patent Classes:
Current U.S. Class:
398155000, 398175000, 398178000, 398180000, 398212000, 398214000
Current International Class:
H04B0100000, H04B0100600
4.
Sato, Kenji, "LIGHT DISPERSION FILTER AND OPTICAL MODULE"
Inventors:
Sato, Kenji
Abstract:
A light dispersion filter is composed of three or more optically transparent layers each having a value equal to the value of the product of the refractive index and thickness of the optically transparent layer and transmitted light, and a plurality of partially reflective layers arranged alternately with the optically transparent layers and having predetermined reflectivities. Alternatively, a light dispersion filter has a plurality of etalon resonators which are arranged in series such that the value of the product of the refractive index of air and the interval of the etalon resonators is equal to the value of the product of the refractive index and thickness of the optically transparent layers.
Assignee:
NEC CORP
Filing Date:
15 December 2003
Grant Date:
24 February 2009
Patent Classes:
Current U.S. Class:
359589000, 359337500, 359588000, 398081000, 398149000
Current International Class:
G02B0052800
5.
Lenz, Gadi; Spector, Magaly, "METHOD FOR DETERMINING THE DISPERSION CHARACTERISTICS OF MINIMUM PHASE FILTERS"
Inventors:
Lenz, Gadi; Spector, Magaly
Abstract:
A method and apparatus for determining the dispersion characteristics of minimum phase filters using substantially only an amplitude response of a minimum phase filter under test includes fitting an amplitude spectrum of the minimum phase filter with a substantially straight line curve, and determining the dispersion characteristics of the minimum phase filter using the straight line curve and the relationships determined by the inventors. Various inventive equations determined by the inventors representative of the relationship between an amplitude response of a minimum phase filter and the dispersion characteristics of the minimum phase filter are used for determining the dispersion characteristics of the minimum phase filter.
Assignee:
LUCENT TECHNOLOGIES INC
Filing Date:
09 June 2003
Grant Date:
26 February 2008
Patent Classes:
Current U.S. Class:
398029000, 398081000, 398147000, 398148000, 398159000, 708323000
Current International Class:
H04B0100800, H04B0170000
6.
Boyd, Robert W.; Heebner, John E., "APPARATUS WITH A SERIES OF RESONATOR STRUCTURES SITUATED NEAR AN OPTICAL WAVEGUIDE FOR MANIPULATING OPTICAL PULSES"
Inventors:
Boyd, Robert W.; Heebner, John E.
Abstract:
Systems and method for manipulating optical pulses to implement an optical switch and for pulse shaping (e.g., pulse compression and/or compression) are disclosed. In one embodiment, the system comprises an optical switch apparatus that includes a plurality of resonators optically coupled to a waveguide, two output waveguides, an input light source, a control light source. The system selects some of the input signals emitted from the input light course using control signals emitted from the control light source to route to one of the output waveguides. In another embodiment, the system includes a waveguide optically coupled to a plurality of resonators, input light source, optional resonator modules that can change the refractive index of the resonators, and an optional amplifier. This system can change the shape of the pulses by changing a number of parameters, such as the incoming pulse amplitude and/or the refractive index of the resonators.
Assignee:
UNIVERSITY OF ROCHESTER
Filing Date:
21 March 2003
Grant Date:
17 July 2007
Patent Classes:
Current U.S. Class:
385027000, 372097000, 385030000
Current International Class:
G02B0062600, G02B0064200
7.
Sorin, Wayne V.; Kim, Byoung Yoon; Vakoc, Ben, "METHODS AND APPARATUSES TO PROVIDE A TUNABLE CHROMATIC DISPERSION COMPENSATOR"
Inventors:
Sorin, Wayne V.; Kim, Byoung Yoon; Vakoc, Ben
Abstract:
Various methods, systems, and apparatuses in which a chromatic dispersion compensation module includes an input fiber, an output fiber, a lens, and an etalon resonator. The input fiber has a first core with a center. The output fiber has a second core with a center. The input fiber is adjacent to the output fiber. The spacing between the center of the first core and the center of the second core is affixed to less than one hundred and twenty microns. The input fiber routes an optical signal to a lens. The lens routes the optical signal to the etalon resonator. The etalon resonator has reflectors with fixed reflectivity and a variable optical length to induce a wavelength-dependent delay into the optical signal. The etalon resonator routes the optical signal to the output fiber through the lens.
Assignee:
NOVERA OPTICS INC
Filing Date:
22 April 2004
Grant Date:
07 June 2005
Patent Classes:
Current U.S. Class:
385027000, 398081000
Current International Class:
G02B0062600000
8.
Vakoc, Ben, "VARIOUS METHODS AND APPARATUSES FOR A TUNABLE CHROMATIC DISPERSION COMPENSATOR"
Inventors:
Vakoc, Ben
Abstract:
Various methods, apparatuses, and systems in which a chromatic dispersion compensation module includes a beam spatial orientation device to separate an optical signal into a first polarized light signal and a second polarized light signal. The second polarized light signal has the posited polarization of the first polarized signal. A wavelength-dependant delay path couples to the beam spatial orientation device. A polarization rotator couples to the wavelength-dependant delay path such that the first polarized light signal reflects into the wavelength-dependant delay path in substantially the opposite direction of the second polarized light signal.
Assignee:
NOVERA OPTICS INC
Filing Date:
06 February 2002
Grant Date:
12 October 2004
Patent Classes:
Current U.S. Class:
359484050, 359486030, 359489040, 359489050, 359489060, 359489070, 359489090, 359615000, 398081000, 398147000
Current International Class:
G02B0050400000
9.
Sorin, Wayne V.; Kim, Byoung Yoon; Vakoc, Ben, "METHODS AND APPARATUSES TO PROVIDE A TUNABLE CHROMATIC DISPERSION COMPENSATOR"
Inventors:
Sorin, Wayne V.; Kim, Byoung Yoon; Vakoc, Ben
Abstract:
Various methods, systems and apparatuses in which a chromatic dispersion compensation module includes an input fiber, an output fiber, a lens, and an etalon resonator. The input fiber has a first core with a center. The output fiber has a second core with a center. The input fiber is adjacent to the output fiber. The spacing between the center of the first core and the center of the second core is affixed to less than one hundred and twenty microns. The input fiber routes an optical signal to lens. The lens routes the optical signal to the etalon resonator. The etalon resonator has reflectors with fixed reflectivity and a variable optical length to induce a wavelength-dependent delay into the optical signal. The a etalon resonator routes the optical signal to the output fiber through the lens.
Assignee:
NOVERA OPTICS INC
Filing Date:
31 May 2002
Grant Date:
07 September 2004
Patent Classes:
Current U.S. Class:
385027000, 385033000, 385036000, 385043000
Current International Class:
G02B0062600000
10.
Zhou, Gan; Wu, Kuang-Yi; Cheng, Chi-Hao, "ADJUSTABLE CHROMATIC DISPERSION COMPENSATION"
Inventors:
Zhou, Gan; Wu, Kuang-Yi; Cheng, Chi-Hao
Abstract:
An interferometer receives an input optical signal and outputs a signal after changing at least the dispersion of said signal. At least portions of the interferometer are adjustable to adjust at least a first dispersion parameter. Examples of dispersion parameters which are adjustable include dispersion magnitude, center wavelengths and waveshapes or slopes. Preferably the dispersion in the output signal is substantially reduced or substantially eliminated, compared to the dispersion of the input signal. By providing for adjustability of one or more dispersion parameters, a dispersion compensator can be appropriately adjusted for use in a variety of applications.
Assignee:
CHORUM TECHNOLOGIES LP
Filing Date:
01 December 2000
Grant Date:
06 May 2003
Patent Classes:
Current U.S. Class:
398158000, 356477000, 356491000, 398101000, 398141000
Current International Class:
H04B0100000000, H04B0101200000, H04J0140800000, G01B0090200000
11.
Sardesai, Harshad, "WDM OPTICAL COMMUNICATION SYSTEM HAVING A DISPERSION SLOPE COMPENSATING ELEMENT"
Inventors:
Sardesai, Harshad
Abstract:
Consistent with the present invention, in-fiber Bragg gratings are used to demultiplex optical signals in a WDM optical communication system. The in-fiber Bragg gratings also perform dispersion compensation of the selected optical signals. As a result, additional segments of DCF for further dispersion compensation are rendered unnecessary. Improved performance is thus achieved with an inexpensive and simplified system design.
Assignee:
CIENA CORP
Filing Date:
17 February 2000
Grant Date:
18 February 2003
Patent Classes:
Current U.S. Class:
359305000, 250227120, 250227140, 359237000, 385010000, 385031000, 385037000, 398081000
Current International Class:
G02F0013300000, G02F0012950000, H04J0140200000, H04B0100000000
12.
Cheng, Chi-Hao; Liu, Jian-Yu; Wu, Kuang-Yi; Wong, Charles, "DISPERSION COMPENSATION FOR OPTICAL SYSTEMS"
Inventors:
Cheng, Chi-Hao; Liu, Jian-Yu; Wu, Kuang-Yi; Wong, Charles
Abstract:
A stacked waveplate device that performs an optical wavelength filtering function is described which provides dispersion with a first magnitude and a first sign for a first optical path having a first output polarization and which provides a second dispersion with a substantially equal but oppositely-signed dispersion for a second optical path defining an output having an orthogonal polarization to the polarization of said first output path. Optical paths are configured to pass through first and second stacked waveplate devices sequentially with the optical dispersion of said second device having an approximately equal magnitude but opposite sign compared to the optical dispersion of the first optical stacked waveplate devices so as to provide canceling or compensation of optical dispersion. A device is configured to use cancellation or compensation of dispersion in sequential stacked waveplate devices to provide outputs with characteristics similar to outputs of previous stacked waveplate devices but with substantially reduced dispersion characteristics.
Assignee:
CHORUM TECHNOLOGIES LP
Filing Date:
20 December 1999
Grant Date:
28 May 2002
Patent Classes:
Current U.S. Class:
398158000, 398045000, 398065000, 398101000, 398152000
Current International Class:
H04B0100000000, H04B0101200000, H04J0140600000
13.
Dong, Liang, "ASYMMETRIC LOW DISPERSION BRAGG GRATING FILTER"
Inventors:
Dong, Liang
Abstract:
A Bragg grating filter is provided for use in an optical fiber of an optical fiber system. The optical fiber includes a core and a cladding. A plurality of Bragg grating segments are formed into the core of the optical fiber. Each grating element is defined by periodic variations in the refractive index. The period variations in the refractive index have a spatially asymmetric index of modulation, such that dispersion of the reflection at one end of the grating element can be decreased at the expense of increased dispersion of reflection at the other end of the grating element.
Assignee:
CORNING INC
Filing Date:
31 August 1999
Grant Date:
21 August 2001
Patent Classes:
Current U.S. Class:
385037000, 385129000
Current International Class:
G02B0063400000
