Abstract: A frequency resolution for measuring transmission characteristics of a device under test is increased. With a measuring device including a first terahertz light generator that generates incident light, a second terahertz light generator that generates reference light having an optical frequency f1?f2?fIF different from an optical frequency f1?f2 of the incident light by a constant difference frequency fIF, a terahertz light detector which outputs an light detection signal having the difference frequency fIF based on response light obtained by making the incident light incident to an optical fiber and the reference light, and a network analyzer that receives the light detection signal, thereby measuring characteristics of the optical fiber, a spectrum of the incident light (terahertz light) incident to the optical fiber includes the carrier frequency (f1?f2), but does not include sideband frequencies (f1?f2±fIF). It is thus possible to reduce the effective spectrum width of the incident light.

Abstract: An object of the present invention is to enable a change in a frequency for which an electric signal based on an optical signal is measured by a spectrum analyzer.

Abstract: A frequency resolution for measuring transmission characteristics of a device under test is increased. With a measuring device including a first terahertz light generator that generates incident light, a second terahertz light generator that generates reference light having an optical frequency f1?f2?fIF different from an optical frequency f1?f2 of the incident light by a constant difference frequency fIF, a terahertz light detector which outputs an light detection signal having the difference frequency fIF based on response light obtained by making the incident light incident to an optical fiber and the reference light, and a network analyzer that receives the light detection signal, thereby measuring characteristics of the optical fiber, a spectrum of the incident light (terahertz light) incident to the optical fiber includes the carrier frequency (f1?f2), but does not include sideband frequencies (f1?f2±fIF). It is thus possible to reduce the effective spectrum width of the incident light.

Abstract: A device for measuring ?PMD includes a polarization controller (12) that allows first (second) incident light, in a synthetic incident light to an object to be measured (30), to be in line with a p-polarization (s-polarization) axis in a polarization separator (16). The phase shift equivalent value (optical angle frequency differentiation) and amplitude equivalent value (square value) of a first (second) incident light component in an output from the polarization separator (16) measured by a first (second) measuring unit (20a, 20b) are respectively the phase shift equivalent value and amplitude equivalent value of a first column T11, T21 (second column T12, T22) when the transfer function matrix of the object (30) is a 2×2 matrix to thereby allow a control unit (2) to determine the polarization mode dispersion ?PMD of the object (30).

Abstract: A polarization mode dispersion measuring device reduced in time required to measure polarization mode dispersion ?PMD. A polarization controller (12) allows a first (second) incident light to apply a synthetic incident light to an object to be measured (30) in line with a p-polarization axis (s-polarization axis) in a polarization separator (16). Accordingly, the phase shift equivalent value (optical angle frequency differentiation) and amplitude equivalent value (square value) of a first incident light component (second incident light component) in an output from the polarization separator (16) measured by a first measuring unit (20a) (second measuring unit (20b)) are respectively the phase shift equivalent value and amplitude equivalent value of a first column T11, T21 (second column T12, T22) when the transfer function matrix of the object to be measured (30) is a 2×2 matrix to thereby allow a control unit (2) to determine the polarization mode dispersion r PMD of the object to be measured (30).

Abstract: An apparatus is provided which is capable of measuring the polarization mode dispersion of an objective without changing a wavelength of an angle frequency of light incident upon the objective.

Abstract: The object of the present invention is to provide an apparatus that can perform measurement of chromatic dispersion, even if the wavelength of variable-wavelength light source and that of fixed-wavelength light source for reference are identical with each other. The variable-wavelength light generated by a variable-wavelength light source 12 is subjected to intensity modulation to a frequency f by a first optical modulator 15a and transmitted from one end 30a to the other end 30b of an optical fiber 30. The fixed-wavelength light generated by a fixed-wavelength light source 14 is subjected to intensity modulation to a frequency f by a second optical modulator 15b and transmitted from the other end 30b to the one end 30a of optical fiber 30. Therefore, it is possible to separately obtain the variable-wavelength light and fixed-wavelength light transmitted through the optical fiber 30 using a second directional coupler 28 and a first directional coupler 26, respectively, regardless of wavelengths thereof.

Abstract: The object of the present invention is to provide an apparatus that can perform measurement of chromatic dispersion, even if the wavelength of variable-wavelength light source and that of fixed-wavelength light source for reference are identical with each other.