OLOF GOERAN SAHLEN · Institutional Repository of Xi'an Institute of Optics and Fine Mechanics, Chinese Academy of Sciences (Xian Institute of Optics and Precision Mechanics) · 1994
A wavelength selective optical filter (20) comprises a grating structure arranged in a waveguide. The grating structure comprises two controllable grating sections (1, 2) electrically isolated from each other which have different grating periods ( LAMBDA 1, LAMBDA 1). The waveguide may be formed in a semiconductor material and the refractive index of each grating controlled by injection currents I1, I2.
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Dr. Jan W. Gooch · 2007
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Silvia E. Braslavsky, K. N. Houk · IUPAC Standards Online · 2016
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HATAYAMA, HITOSHI, NISHIMURA, MASAYUKI · Institutional Repository of Xi'an Institute of Optics and Fine Mechanics, Chinese Academy of Sciences (Xian Institute of Optics and Precision Mechanics) · 2003
A main optical path disposed between light input and output ends and an auxiliary optical path disposed so as to correspond to the main optical path are optically coupled to each other with first, second, and third optical couplers. The respective optical path lengths of main and auxiliary optical paths differ from each other between the first and second optical couplers and between the second and third optical couplers. Between the first and second optical couplers and between the second and third optical couplers, at least one of the main and auxiliary optical paths is provided with temperature adjusting means for adjusting the temperature of the corresponding optical path.
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HATAYAMA, HITOSHI, NISHIMURA, MASAYUKI · Institutional Repository of Xi'an Institute of Optics and Fine Mechanics, Chinese Academy of Sciences (Xian Institute of Optics and Precision Mechanics) · 2003
A main optical path disposed between light input and output ends and an auxiliary optical path disposed so as to correspond to the main optical path are optically coupled to each other with first, second, and third optical couplers. The respective optical path lengths of main and auxiliary optical paths differ from each other between the first and second optical couplers and between the second and third optical couplers. Between the first and second optical couplers and between the second and third optical couplers, at least one of the main and auxiliary optical paths is provided with temperature adjusting means for adjusting the temperature of the corresponding optical path.
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Martin H. Weik · 2000
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POUSTIE, ALISTAIR, JAMES, FINLAYSON, NEIL · Institutional Repository of Xi'an Institute of Optics and Fine Mechanics, Chinese Academy of Sciences (Xian Institute of Optics and Precision Mechanics) · 2001
An optical filter comprises a multi-mode waveguide (W2) and a single-mode waveguide (W1, W3) coupled in series, the interference of different modes at the multiple-mode/single-mode interface being effective to filter an optical signal propagating through the waveguides to provide a desired wavelength response characteristic. The offset between the waveguides may be varied to control the filter characteristic. The filter may be formed in the cavity of a laser to produce an output having a comb-filter characteristic. It may be used as channel selector in WDM systems.
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Jan W. Gooch · 2011
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OLOF GOERAN SAHLEN · Institutional Repository of Xi'an Institute of Optics and Fine Mechanics, Chinese Academy of Sciences (Xian Institute of Optics and Precision Mechanics) · 1994
A wavelength selective optical filter (20) comprises a grating structure arranged in a waveguide. The grating structure comprises two controllable grating sections (1, 2) electrically isolated from each other which have different grating periods ( LAMBDA 1, LAMBDA 1). The waveguide may be formed in a semiconductor material and the refractive index of each grating controlled by injection currents I1, I2.
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2014
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Australian National University · ANU Open Research (Australian National University) · 2019
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YAMAMOTO TAKAYUKI, TANAKA KAZUHIRO · Institutional Repository of Xi'an Institute of Optics and Fine Mechanics, Chinese Academy of Sciences (Xian Institute of Optics and Precision Mechanics) · 1992
PURPOSE:To provide an optical wavelength filter for selecting one optional wavelength from a plurality of wavelengths in wavelength multiplex transmission and exchange of light, which is usable within a wider wavelength range without limiting the used wavelength range to areas within both sub-modes with a main mode as the center. CONSTITUTION:In an optical wavelength filter driven by a driving current less than a threshold current, which filter is provided with a semiconductor substrate 1, a wave guide layer 2 formed on the semiconductor substrate 1, a diffraction grating formed on the wave guide layer 2, a lambda/4 shift structure part 4 formed on the diffraction grating, an active layer 6 formed on the wave guide layer 2, a clad layer 8 formed on the active layer 6, and both end surfaces subjected to nonreflective treatment, the product of a coefficient of coupling (k) and a resonator length L is a value within the range of 2 to 2.8.
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RIZA, NABEEL A. · Institutional Repository of Xi'an Institute of Optics and Fine Mechanics, Chinese Academy of Sciences (Xian Institute of Optics and Precision Mechanics) · 1994
An optical transversal filter includes a processing system having a light source adapted to be modulated by an input electromagnetic signal and generate a plurality of collimated optical signals, a cascade of optical time delay units sequentially coupled to act upon the collimated optical signals passing from the light source to selectively differentially time delay respective ones of the optical signals, an optical trimmer device coupled to receive the differentially time delayed optical signals and to selectively attenuate respective ones of those signals, and a filter output assembly which receives and sums the optical signals from the trimmer device optically and converts the sum to a corresponding filtered electrical signal, or alternatively, converts the respective optical signals to electrical signals and electrically sums the signals. Each optical time delay unit includes a spatial light modulator having liquid crystal pixels disposed such that the polarization orientation of each respective optical signal is controlled by passing respective optical signals through respective ones of the pixels. Dependent on its polarization orientation, each optical signal passes through a delay assembly optically coupled to the respective spatial light modulator in the optical time delay unit on either a direct path or a delay path.
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NUMAI TAKAAKI · Institutional Repository of Xi'an Institute of Optics and Fine Mechanics, Chinese Academy of Sciences (Xian Institute of Optics and Precision Mechanics) · 1988
PURPOSE:To obtain a large variable tuning width of selected wavelength by interposing a distributed feedback area which has a phase shift structure between plural active areas, coupling the active areas with the distributed feedback area optically, and forming the end surfaces of the active areas in nonreflection structure. CONSTITUTION:The distributed feedback area which has the phase shift structure is interposed between the plural active areas, which are coupled optically with the distributed feedback area; and the end surfaces of the active areas are formed in nonreflection structure. Further, when a relation Eg1<Eg2 is born between the forbidden band width Eg1 of the active layer on a light incidence side and the forbidden band width Eg2 of the active layer on a light projection side as to the active layers in the plural active areas, a more effective element is obtained. Consequently, an optionally wavelength selection is a wavelength-multiplexed signal is made.
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A Bragg, Wavelength-insensitive Fiber, Bragg Grating · 2011
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I. Formicola, A. Longobardo, C. Pinto et al. · CERN Bulletin · 2007
Magnetic-Optical Filter (MOF) is an instrument suited for high precision spectral measurements for its peculiar characteristics. It is employed in Astronomy and in the field of the telecommunications (it is called FADOF there). In this brief paper we summarize its fundamental structure and functioning.
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Daine Wright, Harry J. Schulte · Proceedings of the IEEE · 1968
An off-axis optical cavity has been successfully used as a transversal filter in the frequency domain. With a tap spacing of ∼40 nanoseconds, a square wave frequency response has provided alternating pass and rejection bands ∼12.5 MHz wide.
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I. Formicola, A. Longobardo, C. Pinto et al. · arXiv (Cornell University) · 2007
Magnetic-Optical Filter (MOF) is an instrument suited for high precision spectral measurements for its peculiar characteristics. It is employed in Astronomy and in the field of the telecommunications (it is called FADOF there). In this brief paper we summarize its fundamental structure and functioning.
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TANAKA KAZUHIRO · Institutional Repository of Xi'an Institute of Optics and Fine Mechanics, Chinese Academy of Sciences (Xian Institute of Optics and Precision Mechanics) · 1992
PURPOSE:To provide the optical wavelength filter which has an optical amplification function and, the gain coefft. of which is not substantially changed by a change in the intensity of input light. CONSTITUTION:This optical wavelength filter is constituted so as to have an optical semiconductor device having an active layer 1 which includes a quantum well layer, an optical waveguide layer 3 which is disposed in parallel with the active layer and is formed of the semiconductor of a wider band gap and a diffraction grating 4 structure which is formed near the surface of the optical waveguide layer 3 surface and generates a resonance characteristic and an incident optical system 10 for supplying an input light signal 9 to the active layer of the optical semiconductor device and the optical waveguide layer 3.
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QIAO, LIJIE · Institutional Repository of Xi'an Institute of Optics and Fine Mechanics, Chinese Academy of Sciences (Xian Institute of Optics and Precision Mechanics) · 2019
A tunable optical filter includes sequentially coupled Mach-Zehnder (MZ) interferometers. The first and last interferometers are configured to function as variable power splitter / combiner, whereas the middle interferometer or interferometers have unequal optical paths, creating a desired spectral response of the entire filter. The amplitude of the spectral response can be varied by varying the optical power splitting/combining ratios.
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