Abstract:
Provided is a tunable filter including: a polarization splitter that splits input light into two linearly polarized light rays of mutually orthogonal vibration directions; a wavelength dispersion spectroscopic element that splits the two linearly polarized light rays split by the polarization splitter, into two spectral images having spatial spread in one direction, the two spectral images corresponding to the two linearly polarized light rays; and a reflective spatial modulator device that modulates and reflects linearly polarized light in each wavelength region for the two spectral images independently from each other, where modulated light reflected at the reflective spatial modulator device reenters the wavelength dispersion spectroscopic element and the polarization splitter, thereby splitting and outputting the modulated light, as output light in a wavelength region modulated by the reflective spatial modulator device and output light in a wavelength region not modulated, and input light and reentered light to the polarization splitter and input light and reentered light to the wavelength dispersion spectroscopic element are parallel light fluxes.
Abstract:
PROBLEM TO BE SOLVED: To provide a depolarizing plate that can be simply configured without using a birefringent material of an anisotropic crystal, and a circular dichroic spectral device using the depolarizing plate.SOLUTION: A depolarizing plate 10 includes: a pair of wedge plates 12, 14 comprising two wedge-like plates of an optical isotropic material stacked to give a constant thickness; and wedge plate holding means 16A, 16B holding the pair of wedge plates 12, 14, respectively. The wedge plate holding means 16A, 16B include compressing parts 22, 28 that compress the wedge plates 12, 14, respectively, in directions perpendicular to the thickness direction of the pair of the wedge plates 12, 14. A compression direction C1 of one wedge plate 12 intersects at an angle of 45 degrees with a compression direction C2 of the other wedge plate 14.
Abstract:
PROBLEM TO BE SOLVED: To provide a novel method and apparatus for separating a multi-wavelength optical signal along with a reference signal by wavelength into multiple spectral channels and a reference spectral component. SOLUTION: By aligning the reference spectral component at a predetermined location, the spectral channels simultaneously impinge onto designated locations, e.g., on an array of beam-receiving elements positioned in accordance with the spectral array. The reference spectral component may be further maintained at the predetermined location by way of servo-control, thereby ensuring that the spectral channels stay aligned at the designated locations. The present invention can be used to construct a new line of servo-based optical systems, including spectral power monitors and optical multiplexers/demultiplexers, for WDM optical networking applications. COPYRIGHT: (C)2008,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide a device for controlling light radiation excited and/or backscattered and/or reflected by a sample, including one or a plurality of wavelengths toward various optical exits. SOLUTION: The light radiation is separated into components having different polarizations and the components of excitation radiation and/or detection radiation are affected in terms of polarization by preferably using a double-refraction, acoustooptic or electrooptic medium which modifies the refractive index to an ordinary or extraordinary one. COPYRIGHT: (C)2007,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide a system and a method for accurately detecting very low-power electromagnetic signal. SOLUTION: The system includes a receiver assembly for receiving the signal. The signal includes a sample component, having a sample electric field and a sample polarization, and a reference component, having a reference electric field and a reference polarization offset from the sample polarization. The receiver assembly includes an optical analyzer for processing the signal, using polarimetry and generating a differential electric field, in proportion with a difference between the sample electric field and reference electric field. The optical analyzer decreases the magnitude of a common-mode signal in the differential signal in the receiver by processing the signal by using a polarimetric difference process. The receiver assembly includes an electric field detector for measuring the differential electric field. Noise equivalent power is decreased in the electric field detector by decreasing the common mode amplitude. Advantage lies in that the noise equivalent power is decreased in the electric field, when a small change is measured in the large electric field. COPYRIGHT: (C)2007,JPO&INPIT