摘要:
In a device which extracts an optical interference signal for analyzing the spectrum of light to be measured, the light to be measured is incident to an optical interferometer capable of sweeping an optical path difference and interference light output therefrom is converted into an electric signal to obtain an optical inteference signal. On the other hand, the optical power of the light to be measured is extracted to create an optical power signal, which is provided to a divider, wherein the optical interference signal is divided by the optical power signal to obtain a noise-free optical interference signal.
摘要:
A temperature stabilizer for accurately stabilizing the temperature of an object is provided. The temperature stabilizer stabilizes the temperature of an object to a reference temperature. The temperature stabilizer includes an oscillator provided in proximity to the object, for generating an oscillation signal having a frequency corresponding to an inputted frequency control signal, a phase detector for detecting the phase difference between a feedback signal based on the oscillation signal and a reference clock signal having a predetermined frequency, a loop filter for generating the frequency control signal to synchronize the feedback signal with the reference clock signal based on the output from the phase detector, a comparator for comparing the value of the frequency control signal with a reference value determined corresponding to the reference temperature and an electric heating converter for heating or cooling the object based on the comparison result from the comparator.
摘要:
An average frequency measuring apparatus in which auxiliary gate signals are converted into synchronized gate signals synchronized with either input signals or clock signals; first and second gates are opened by the synchronized gate signals; the input signals and the clock signals having passed through the first and second gates are counted by first and second counters, respectively; and the frequency of the input signals is calculated from the count values of the first and second counters for a plurality of occurrences of the synchronized gate signal. A third counter is provided for counting the number of the synchronized gate signals, and a minimum counting time is calculated by calculating means from the count values of the third and second counters and the set measurement accuracy. When it is detected from the count value of the second or third counter that the actual counting time has been exceeded, measurement is stopped, thereby obtaining measured results of accuracy at least higher than the set measurement accuracy.
摘要:
An optical frequency measurement apparatus of the present invention includes: a coarse light frequency measurer that computes coarse light frequency (Fw) of measured input light based on a reference wavelength that is a wavelength of reference light; a pulsed light source that generates pulsed light including a plurality of optical frequency components with different repetition frequency (fs1) based on reference frequency (Fs) that is frequency of the reference light; a first beat signal generating section that generates a first beat signal having a first difference frequency (fc) that is difference frequency between optical frequency of the pulsed light closest to optical frequency of the measured input light among the plurality of optical frequency components and the optical frequency of the measured input light; a frequency measurer that measures the first difference frequency (fc) of the first beat signal; and an arithmetic section that computes the fine light frequency (Fx) based on the coarse light frequency (Fw), the reference frequency (Fs), the repetition frequency (fs1), and the first difference frequency (fc).
摘要:
A photometer includes a spectrometer that extracts a component of a predetermined wavelength band from incident light, a coupler that branches the predetermined wavelength band component into a first direction and a second direction, an optical switch that includes a first input terminal, a second input terminal, a first output terminal, and a second output terminal, an optical amplifier that receives light from the second output terminal and outputs amplified light, which is obtained by amplifying the light, to an incident light receiving section of the spectrometer, and a photodetector that is connected to the first output terminal and detects light.
摘要:
An input signal and a local oscillator signal are supplied to a harmonic mixer. The local oscillator signal is swept over a frequency range. The output from the harmonic mixer is supplied to an intermediate frequency filter having a preselected frequency response, which provides an output signal when the difference formed by subtracting one of the input signal frequency and one harmonic frequency of the local oscillator signal from the other is equal to the intermediate frequency or when the difference formed by subtracting the other frequency from said one frequency is equal to the intermediate frequency as the local oscillator frequency is swept. By choosing a time interval between the times when the pair of intermediate frequency output signals are obtained, the order of that harmonic of the local oscillator signal with which the intermediate frequency output signal is obtained is determined depending on the frequency of the input signal. Thus, with a chosen time interval, when the frequency sweep of the local oscillator signal is interrupted with the later occurring one of the pair of the intermediate frequency output signals, the frequency of the local oscillator permits, together with the order of selected harmonic which corresponds to the chosen time interval and the direction of the frequency sweep, the frequency of the input signal to be determined. By using a definite time interval between the pair of intermediate frequency signals obtained and adjusting the rate of the frequency sweep, the order of the harmonic which is effective to obtain the intermediate frequency signals can be varied.
摘要:
A minimum-configuration photometer capable of measuring both wavelength characteristics and optical spectral characteristics. The photometer includes an optical amplifier, a spectrometer for taking out a specified wavelength band component from an amplified light, a coupler for branching the specified wavelength band component to two directions, a photoswitch having a first input terminal, a second input terminal, a first output terminal, and a second output terminal, and a photodetecting section wherein the first input terminal is connected with one end of an article being measured, the second input terminal is connected with the coupler, the first output terminal is connected with the photodetecting section, and the second output terminal is connected with the input side of the optical amplifier. The photoswitch connects the second input terminal with the second output terminal, and connects the first input terminal with the first output terminal (wavelength characteristics measuring unit), or connects the second input terminal with the first output terminal, and connects the first input terminal with the second output terminal (spectral analyzer).
摘要:
An optical network analyzer for measuring an optical characteristic of an object to be measured, including: a first multiplexer for multiplexing a first optical signal which has transmitted the object to be measured, and a second optical signal having a frequency different from the first optical signal, and for outputting a third optical signal; a first photoelectrical converter for converting the third optical signal into a first electric signal; and a phase measurement block for comparing phases of the first electric signal and a first reference signal.
摘要:
A polarization state changing apparatus which can change the polarization state of an incident polarized light entering to an optical fiber to any direction and can output is provided. This polarization state changing apparatus, in an embodiment, comprises three polarization plane maintaining optical fibers 10, 20 and 300 which are serially connected at two polarization plane changing parts 30 and 30'. Those three polarization plane maintaining optical fibers are connected at the polarization plane changing parts 30 and 30'so that the optical axes X and Y of the adjacent optical fibers are mutually rotated at an angle of 45 degrees in terms of the fiber axis. Stress application parts for applying stress to each of the polarization plane maintaining optical fibers are provided. In a specific example, each optical fiber is wound around each piezoelectric element cylinder and predetermined stress is applied to each optical fiber by driving those piezoelectric element cylinders by power supplies each of which oscillating frequency and generated voltage are both variable. Also, a polarization degree measuring apparatus using the polarization state changing apparatus is provided to measure degree of polarization accurately and quickly.
摘要:
A synchronizing gate signal is generated in synchronism with an input signal or a clock signal, and first and second gates are opened by the synchronizing gate signal. The input signal having passed through the first gate is counted by a first counter circuit, and the clock signal having passed through the second gate is frequency-divided by a divide-by-10.sup.n frequency divider. An output from the frequency divider is counted by a second counter means. The synchronizing gate signal is generated under the control of a control circuit, and is prevented from being generated when the output from the frequency divider is applied to the control circuit. The n in the frequency-division ratio 1/10.sup.n of the frequency divider and a maximum count P of a third counter circuit are determined from a count of the third counter circuit, a preset measurement accuracy, and a period of the clock signal at the time one output is produced from the frequency divider, the n being set in the frequency divider. The control circuit is caused to generate the synchronizing gate signal. When the output from the frequency divider is obtained, the count is picked up from the first counter circuit and the synchronizing gate signal is generated again in a repetitive process. Each time the output from the frequency divider is obtained, an average frequency is calculated from the counts of the first counter circuit and the second counter circuit. Until the count of the second counter circuit reaches P, a display indicates that a displayed average frequency has the preset measurement accuracy.