CN102243102A - Photoelectric measuring device capable of measuring power and wavelength at same time - Google Patents

Abstract

The invention discloses a photoelectric measuring device capable of measuring power and wavelength at the same time. The photoelectric measuring device comprises an adapter and a signal processing circuit, and is characterized in that: a light splitter, a first photoelectric detector and a second photoelectric detector are arranged behind the adapter; the first photoelectric detector and the second photoelectric detector are connected with the signal processing circuit; the transmissivity of the light splitter changes monotonously with wavelength; the first photoelectric detector and the second photoelectric detector have the same photoelectric conversion efficiency; an included angle between the normal of the light splitter and the light to be detected, which is transmitted by the adapter is 30 to 50 degrees; and transmission light formed after light to be detected, which is transmitted to the beam splitter, is split by the light splitter enters the first photoelectric detector, and reflected light after light splitting enters the second photoelectric detector. The photoelectric measuring device has the advantages that: the transmission light and the reflected light are made to enter the two photoelectric detectors with the same photoelectric conversion efficiency by the light splitter of which the transmissivity changes monotonously with the wavelength, the wavelength value of the light to be detected can be determined according to a ratio of electrical signals of the two photoelectric detectors, and the power value of the light to be detected is computed.

Description

A kind of photoelectric measuring device that can measure power and wavelength simultaneously

Technical field

The present invention relates to a kind of photoelectric measuring device, especially relate to a kind of photoelectric measuring device that can measure power and wavelength simultaneously.

Background technology

A kind of photoelectric measuring device commonly used of light power meter has a wide range of applications in fiber optic communication network, Broadcasting Cable Network construction and O﹠M.The measuring principle of light power meter is: light signal is radiated on the photodetector, and light signal is converted to electric signal, obtains optical power value by counter the pushing away of the measurement of voltage amplitude.For fiber optic communication network and Broadcasting Cable Network, for making full use of the fibre circuit resource, the light signal that a plurality of wavelength are often arranged on an optical fiber is in transmission.Such as, the laser that has tens wavelength on the wave division multiplexing WDM network transmits simultaneously; And for example, use three wavelength of 1310nm, 1490nm and 1550nm on same optical fiber, to transmit different information (use descending 1490nm and up 1310nm wavelength to transmit data and voice, use 1550nm to transmit video) simultaneously in Fiber to the home the network.And,,, then need to know in advance the incident light wavelength for obtaining optical power value accurately because the photoelectric transformation efficiency of photodetector is relevant with wavelength for the measurement of the power of the concrete light signal that is sent to the user.Therefore, a button of selecting wavelength is arranged all on the light power meter,, be converted to the performance number of corresponding wavelength by this button switch test wavelength (1310nm, 1490nm, 1550nm and 1625nm).If but wavelength the unknown of light signal to be measured or the selection of user's wavelength are improper, then can cause measured deviation.The method of grating beam splitting is adopted in traditional wavelength measurement more, and complex structure, bulky can't be integrated in the small-sized test instrumentation.

ILX Lightwave company provides a kind of desk-top instrument that can realize power and wavelength measurement simultaneously, its principle is that incident light is behind semi-permeable mirror, power is divided into two, wherein one road light signal directly is converted to electric signal to detector, another road light signal arrives detector and is converted to electric signal after color filter, utilize the ratio of this two path signal to realize wavelength measurement.Because incident optical signal needs successively process semi-permeable mirror and color filter, loss is big, is unfavorable for acquisition of signal, and the measuring accuracy of power and wavelength is lower.

Summary of the invention

Technical matters to be solved by this invention provides a kind of photoelectric measuring device that can measure power and wavelength simultaneously simple in structure.

The present invention solves the problems of the technologies described above the technical scheme that is adopted: a kind of photoelectric measuring device that can measure power and wavelength simultaneously, comprise adapter and signal processing circuit, be provided with light splitting piece behind the described adapter, first photodetector and second photodetector, described first photodetector links to each other with described signal processing circuit with described second photodetector, the transmissivity of described light splitting piece is with the wavelength monotone variation, described first photodetector has identical photoelectric transformation efficiency with described second photodetector, the angle for the treatment of photometry of the normal of described light splitting piece and described adapter outgoing is 30～50 °, the transmitted light of photometry after described light splitting piece beam split for the treatment of that incides on the described light splitting piece enters described first photodetector, and the reflected light after the beam split enters described second photodetector.

The service band of described light splitting piece is 800nm～1700nm, and in this wavelength band, the transmissivity of described light splitting piece is with the wavelength monotone variation.

Described light splitting piece is ZnS or GaAs diaphragm or optical filter.

Described adapter is any one in FC type adapter, ST type adapter, LC type adapter and the SC type adapter of using always in the optical communication.

Compared with prior art, the invention has the advantages that and utilize a kind of transmissivity incident light to be divided into two with the light splitting piece of wavelength monotone variation, transmitted light and reflected light enter first photodetector and second photodetector respectively, and first photodetector has identical photoelectric transformation efficiency with second photodetector, ratio according to the electric signal of first photodetector and second photodetector can be determined light wavelength value to be measured easily, can calculate the performance number for the treatment of photometry easily again according to the wavelength value of determining and the electric signal of first photodetector or second photodetector.Light splitting piece had both played the effect of beam splitting, play acting on of filtering again, realize treating the power and the wavelength measurement of photometry simultaneously, the power attenuation of whole optical path is low, can realize higher power and wavelength measurement precision, and apparatus structure is simple, volume is little, cost is low, is particluarly suitable for widespread use in fiber optic communication network and the Broadcasting Cable Network.

Description of drawings

Fig. 1 is the structural representation of measurement mechanism of the present invention;

Fig. 2 is the transmission spectrum of the present invention as a kind of diaphragm of light splitting piece;

Fig. 3 is the transmission spectrum of the present invention as a kind of optical filter of light splitting piece.

Embodiment

Embodiment describes in further detail the present invention below in conjunction with accompanying drawing.

Embodiment 1

As shown in Figure 1, a kind of photoelectric measuring device that can measure power and wavelength simultaneously, comprise adapter 1, light splitting piece 2, first photodetector 3, second photodetector 4 and signal processing circuit 5, light splitting piece 2 is a ZnS s diaphragm, be of a size of 1.4mm*1.4mm*1.0mm, the service band of light splitting piece 2 from visible light until far infrared, cover our required service band 800nm～1700nm, in this wavelength band, the transmissivity T of light splitting piece 2 (λ) is with the wavelength monotone variation, as shown in Figure 2.As can be seen from Figure 2, the transmissivity at the 800nm place is 11%, and the transmissivity at the 1700nm place is 35%, and transmissivity is lower with the wavelength change rate, but can discern common signal wavelength.Treat that photometry S1 incides on the light splitting piece 2 through adapter 1, the transmitted light S2 of light splitting piece 2 enters first photodetector 3, and the reflected light S3 of light splitting piece 2 enters second photodetector 4.First photodetector 3 has identical photoelectric transformation efficiency η (λ) with second photodetector 4, is the InGaAs PIN of the G8370-03 type of Japanese shore pine company.In order effectively to separate transmitted light S2 and the reflected light S3 and the incident light S1 of light splitting piece 2, the angle for the treatment of photometry S1 of the normal of light splitting piece 2 and adapter 1 outgoing is 45 °, and adapter is a FC type adapter.

First photodetector 3 links to each other with signal processing circuit 5 with second photodetector 4, signal processing circuit 5 provides driving voltage and electric signal to amplify for first photodetector 3 and second photodetector 4, and be used to gather the electric signal of first photodetector 3 and second photodetector 4, and calculate power and the wavelength value for the treatment of photometry S1.In the present embodiment, the GaAs diaphragm is respectively 15% and 31% in the transmissivity at 850nm and 1625nm place, this moment, the electric signal ratio of first photodetector 3 and second photodetector 4 was respectively 0.176 and 0.449 (this ratio can by standard wavelength's laser calibration), therefore was very easy to these two wavelength of identification.Spectral response characteristic according to the InGaAs photodiode, the responsiveness of 850nm and 1625nm is respectively 0.15A/W and 0.92A/W (this numerical value can by the laser calibration of standard wavelength and power), electric signal according to first photodetector 3 and second photodetector 4 can calculate incident optical power.

The concrete wavelength and the computing method of power are: first photodetector 3 and second photodetector 4 receive the luminous power P of the transmitted light S2 of light splitting piece 2 respectively ₁=P ₀The luminous power P of T (λ) and reflected light S3 ₂=P ₀(1-T (λ)), P ₀For treating the luminous power of photometry S1; Signal processing circuit 5 is gathered the electric signal V of first photodetector 3 ₁=η (λ) P ₀The electric signal V of the T (λ) and second photodetector 4 ₂=η (λ) P ₀(1-T (λ)), wherein η (λ) is the photoelectric transformation efficiency of first photodetector 3 and second photodetector 4, and is relevant with light wavelength to be measured.

Ratio according to the electric signal of first photodetector 3 and second photodetector 4

Can determine light wavelength value λ to be measured:

$\frac{V_1}{{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="HDA0000057218480000012.png"\; state="\{\{state\}\}">V</figure-callout>}}_2}=\frac{T\left(\mathrm{\&lambda;}\right)}{1-T\left(\mathrm{\&lambda;}\right)}---\left(1\right)$

Because transmissivity T (λ) monotone variation in whole service band scope of light splitting piece 2, and be known quantity, therefore can calculate easily and determine light wavelength value λ to be measured.

After the wavelength X for the treatment of photometry S1 was determined, the photoelectric transformation efficiency η (λ) according to photodetector can calculate the performance number for the treatment of photometry easily:

${\mathrm{<figure-callout\; id="0"\; label="P"\; filenames="HDA0000057218480000012.png"\; state="\{\{state\}\}">P</figure-callout>}}_0=\frac{{\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="HDA0000057218480000012.png"\; state="\{\{state\}\}">V</figure-callout>}}_1}{\mathrm{\&eta;}\left(\mathrm{\&lambda;}\right)T\left(\mathrm{\&lambda;}\right)}=\frac{{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="HDA0000057218480000012.png"\; state="\{\{state\}\}">V</figure-callout>}}_2}{\mathrm{\&eta;}\left(\mathrm{\&lambda;}\right)(1-T\left(\mathrm{\&lambda;}\right))}=\frac{{\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="HDA0000057218480000012.png"\; state="\{\{state\}\}">V</figure-callout>}}_1+{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="HDA0000057218480000012.png"\; state="\{\{state\}\}">V</figure-callout>}}_2}{\mathrm{\&eta;}\left(\mathrm{\&lambda;}\right)}---\left(2\right)$

Embodiment 2

The structure of present embodiment is identical with enforcement 1, and difference is selected optical filter for use at light splitting piece 2.This light splitting piece 2 adopts optically coated mode to realize, can be by optimizing the transmission spectrum of the thicknesses of layers and number of plies realization with the wavelength monotone variation.Present embodiment adopts the linear change optical filter LTF081 of Canadian Iridian company, be of a size of 1.5mm*1.5mm*1.0mm, service band is from 1520nm～1620nm, maximum transmission rate is 90%1520nm, minimum transmittance 10%1620nm, the wavelength band internal transmission factor reduces with wavelength linear, and the transmission change rate is 0.8%/nm, distinguishable rate goes out the wavelength variations less than 0.2nm, and the signal wavelength that is fit to dense wave division multipurpose DWDM Networks of Fiber Communications is surveyed (the about at interval 0.8nm of signal wavelength).

Claims (4)

1. the photoelectric measuring device that can measure power and wavelength simultaneously, comprise adapter and signal processing circuit, it is characterized in that being provided with light splitting piece behind the described adapter, first photodetector and second photodetector, described first photodetector links to each other with described signal processing circuit with described second photodetector, the transmissivity of described light splitting piece is with the wavelength monotone variation, described first photodetector has identical photoelectric transformation efficiency with described second photodetector, the angle for the treatment of photometry of the normal of described light splitting piece and described adapter outgoing is 30～50 °, the transmitted light of photometry after described light splitting piece beam split for the treatment of that incides on the described light splitting piece enters described first photodetector, and the reflected light after the beam split enters described second photodetector.

2. a kind of photoelectric measuring device that can measure power and wavelength simultaneously as claimed in claim 1, the service band that it is characterized in that described light splitting piece is 800nm～1700nm, in this wavelength band, the transmissivity of described light splitting piece is with the wavelength monotone variation.

3. a kind of photoelectric measuring device that can measure power and wavelength simultaneously as claimed in claim 1 or 2 is characterized in that described light splitting piece is ZnS or GaAs diaphragm or the transmissivity optical filter with the wavelength monotone variation.

4. a kind of photoelectric measuring device that can measure power and wavelength simultaneously as claimed in claim 1 is characterized in that described adapter is any one in FC type adapter, ST type adapter, LC type adapter and the SC type adapter of using always in the optical communication.

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