Abstract:
[Problem] To provide a camera with high sensitivity even if an output to the outside is weak. [Solution] This camera includes a light source 3, a demultiplexing unit 5 which demultiplexes light from the light source 3 into first demultiplexed light and second demultiplexed light, a first modulator 7 which modulates the first demultiplexed light to obtain a modulated signal, an emission unit 9 which emits the modulation signal modulated by the first modulator 7, and a phase imparting means 11 which imparts a plurality of types of phase shifts to the second demultiplexed light to obtain phase-imparted local light. The camera further includes a multiplexing unit 13 which multiplexes light incident from the outside of the camera and the phase-imparted local light and obtains multiplexed light, a light receiving element 17 which detects the multiplexed light, and includes a light receiving unit 15, and an analysis processing unit 19 which, on the basis of the multiplexed light received by the light receiving element 17, analyzes the position of a subject or the distance between the subject and the camera.
Abstract:
[Problem] To provide a novel optical network which can be used as an in-vehicle optical backbone network and exhibits high capacity, low delay, low power consumption, low noise and low cost. [Solution] An optical network system, wherein: a signal processing unit 13 controls a light source 11, and generates an optical signal which includes an information portion to be read by one of the gateway units 5a, and a continuous light portion to be written thereby; a network control unit 15 generates an electrical signal which designates a gate y unit 5a and pertains to whether the information incorporated into the optical signal is to be read or written; and when designated by the electrical signal, each of the gateway units 5a transfers information to and from an electronic control unit 7, and reads information included in the corresponding optical signal or writes information in the continuous light portion, on the basis of the information included in the electrical signal about whether to read or write information.
Abstract:
To provide a photodetector which enables reception of massively parallel optical communication, and with which a large volume of data for multi-mode transmission or multi-core transmission can be received instantaneously at once. A photodetector comprising a two-dimensional photodetector array in which a plurality of photodetectors 9 are arranged in a two-dimensional array, and which includes a wire 12 having a width of not more than 4 μm between the plurality of photodetectors. Each of the photodetectors has a light reception area with a side measuring not more than 100 μm. The plurality of photodetectors arranged in a two-dimensional array are spaced apart from each other by not less than 20 μm.
Abstract:
To provide a method and device capable of easily measuring the CMRR vs. frequency characteristics of an optical receiver. Light having a measurement frequency (ω [hz]) is split into two different paths, and a first optical two-tone signal, which is signal light and has a frequency difference (ω−Δω [hz]), and a second optical two-tone signal, which is local light and has a frequency difference (ω-Δω [hz]), are obtained and input into a coherent receiver to be measured, wherein electrical signals output from the receiver are measured to obtain both the ratio of the intensity of a signal component having the frequency ω−Δω [hz] to the intensity of a signal component having the frequency ω [hz], which corresponds to the CMRR on the signal light side, and the ratio of the intensity of a signal component having the frequency ω+Δω [hz] to the intensity of the signal component having the frequency ω [hz], which corresponds to the CMRR on the local light side.
Abstract:
There is provided a photoelectric converter that converts an optical signal into an electrical signal for amplification, the photoelectric converter including a photoelectric conversion element that converts the optical signal into an electrical signal and outputs the electrical signal from an output terminal, a high-frequency amplifier that includes an input terminal of an electrical signal output from the output terminal and a DC cut-off capacitor which is disposed at an output stage of the input terminal and is serially connected to the input terminal and that amplifies the electrical signal, and an inductance element that is disposed between a bias power supply applying bias voltage or bias current to the photoelectric conversion element and the input terminal and which is connected in parallel to the DC cut-off capacitor.
Abstract:
PROBLEMSTo provide a method for evaluating characteristics of MZ interferometers in an optical modulator having a plurality of MZ interferometers.MEANS FOR SOLVING PROBLEMSWhen an optical modulator includes a plurality of MZ interferometers, the 0-degree component contains a signal derived from an MZ interferometer other than the MZ interferometers for evaluating the characteristic. For this, it is impossible to accurately evaluate the characteristic of the MZ interferometers. The present invention does not use the 0-degree component normally having the highest intensity. That is, the characteristic of the MZ interferometers are evaluated by using a side band intensity of the component other than the 0-degree component.
Abstract:
The optical modulator includes optical modulation units. The plurality of optical modulation units is disposed in parallel on the same substrate. One input waveguide branches off to be connected to the Mach-Zehnder type optical waveguide of each optical modulation unit, and an entire optical waveguide is formed such that outputs from the Mach-Zehnder type optical waveguides are combined and output through one output waveguide. A modulation signal with the same intensity is applied to a modulation electrode of each optical modulation unit. In at least some of the optical modulation units, mechanical structures including the modulation electrodes of the optical modulation units are configured such that an amplitude value of an optical output modulated by the modulation signal of the optical modulation unit is ½n (n is a natural number) of a maximum amplitude value in other optical modulation units.
Abstract:
To provide a method whereby a bias voltage capable of easily realizing a required extinction ratio can be controlled by utilizing a high-extinction ratio modulator even when a generic AD converter/control board is used, and a device for realizing the method. In the present invention, the step quantity (variation quantity) ΔV of a control voltage is no more than 0.1 times the half-wave voltage Vπ [V]. For example, in the case of searching for the minimum point, the light intensity is measured when a bias that is larger by the step voltage ΔV and a bias that is smaller by the step voltage ΔV are applied, the current bias voltage being used as a reference, and the bias voltage is moved toward the smaller of the measured light intensities. The process of setting the moved bias voltage as a reference, comparing the light intensities for the bias points in both neighboring positions, and changing the reference bias voltage is then repeated. A configuration may be adopted whereby ΔV then gradually decreases in accordance with a predetermined algorithm.
Abstract:
To provide a method for performing phase control of coherent two light wave signals while maintaining coherence in the state of the light signal, and a device which realizes such a method, there is provided, as illustrated in FIG. 1, a phase adjustment device 1 for two light waves including: a two light wave source 3, a wavelength separator 5, a first phase modulator 7, and a second phase modulator 9, whereby coherent two light waves are used as input signals to perform wavelength separation of those input signals thereafter to control optical phases of the respective light signals thereafter to multiplex them by using a multiplexer 11, thus to be able to obtain an output signal of which optical phase has been adjusted.
Abstract:
A high-speed communication control system is provided to resolve the problem of transmission delay, while a communication capacity is ensured.A communication system includes a transmission station 13 and a reception station 15. A communication system 17 includes an optical fiber line 19 and a wireless path 21 that connect the transmission station 13 to the reception station 15 so that information is transmitted and received. The transmission station 13 includes a communication control unit 11 that controls a communication path. The reception station 15 is able to communicate with the transmission station 13. The communication control unit 11 controls whether the information is transmitted to the reception station 15 via one of the optical fiber line 19 and the wireless path 21.