CN102243102B - 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 simultaneously measure power and wavelength

Technical field

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

Background technology

A kind of conventional photoelectric measuring device 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 photodetector, and light signal is converted to electric signal, is back-calculated to obtain optical power value by the measurement of voltage amplitude.For fiber optic communication network and Broadcasting Cable Network, for making full use of fibre circuit resource, on an optical fiber, often there is the light signal of multiple wavelength in transmission.Such as, on wave division multiplexing WDM network, may there is the laser of tens wavelength to transmit simultaneously; And for example, in Fiber to the home network, use 1310nm, 1490nm and tri-wavelength of 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.And for the measurement of power of concrete light signal that is sent to user, because the photoelectric transformation efficiency of photodetector is relevant to wavelength, for obtaining optical power value accurately, need to know in advance incident light wavelength.Therefore, on light power meter, all there is a button of selecting wavelength, by this button switch test wavelength (1310nm, 1490nm, 1550nm and 1625nm), be converted to the performance number of corresponding wavelength.If but wavelength the unknown of light signal to be measured or the selection of user's wavelength are improper, can cause measured deviation.Traditional wavelength measurement adopts the method for grating beam splitting more, and complex structure, bulky cannot be integrated in small-sized test instrumentation.

ILX Lightwave company provides a kind of desk-top instrument that can simultaneously realize power and wavelength measurement, its principle is that incident light is after semi-permeable mirror, power is divided into two, wherein a road light signal is directly converted to electric signal to detector, another road light signal arrives detector and is converted to electric signal after color filter, utilizes 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 large, 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 is to provide a kind of photoelectric measuring device that can simultaneously measure power and wavelength simple in structure.

The present invention solves the problems of the technologies described above adopted technical scheme: a kind of photoelectric measuring device that can simultaneously measure power and wavelength, comprise adapter and signal processing circuit, after described adapter, be provided with light splitting piece, the first photodetector and the second photodetector, the first described photodetector is connected with described signal processing circuit with the second described photodetector, the transmissivity of described light splitting piece is with wavelength monotone variation, the first described photodetector and the second described photodetector have identical photoelectric transformation efficiency, 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 after described light splitting piece light splitting until photometry inciding on described light splitting piece enters the first described photodetector, reflected light after light splitting enters the second described 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 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 SC type adapter conventional in optical communication.

Compared with prior art, the invention has the advantages that and utilize a kind of transmissivity with the light splitting piece of wavelength monotone variation, incident light to be divided into two, transmitted light and reflected light enter respectively the first photodetector and the second photodetector, and the first photodetector and the second photodetector have identical photoelectric transformation efficiency, can determine easily light wavelength value to be measured according to the ratio of the electric signal of the first photodetector and the second photodetector, can calculate easily again according to the electric signal of definite wavelength value and the first photodetector or the second photodetector the performance number for the treatment of photometry.Light splitting piece had both played the effect of beam splitting, play again acting on of filtering, realize power and the wavelength measurement for the treatment of photometry simultaneously, the power attenuation of whole light 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 Broadcasting Cable Network.

Brief description of the drawings

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

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

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

Embodiment

Below in conjunction with accompanying drawing, embodiment is described in further detail the present invention.

Embodiment 1

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

The first photodetector 3 is connected with signal processing circuit 5 with the second photodetector 4, signal processing circuit 5 provides driving voltage and electric signal to amplify to the first photodetector 3 and the second photodetector 4, and for gathering the electric signal of the first photodetector 3 and the second photodetector 4, and calculate power and the wavelength value for the treatment of photometry S1.In the present embodiment, GaAs diaphragm is respectively 15% and 31% in the transmissivity at 850nm and 1625nm place, now the electric signal ratio of the first photodetector 3 and the second photodetector 4 is respectively 0.176 and 0.449 (this ratio can by standard wavelength's laser calibration), is therefore very easy to these two wavelength of identification.According to the spectral response characteristic of 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), according to the electric signal of the first photodetector 3 and the second photodetector 4, can calculate incident optical power.

Concrete wavelength and the computing method of power are: the first photodetector 3 and the second photodetector 4 receive respectively the luminous power P of the transmitted light S2 of light splitting piece 2₁=P₀the luminous power P of T (λ) and reflected light S3₂=P₀(1-T (λ)), P₀for treating the luminous power of photometry S1; Signal processing circuit 5 gathers the electric signal V of the first photodetector 3₁=η (λ) P₀the electric signal V of T (λ) and the second photodetector 4₂=η (λ) P₀(1-T (λ)), wherein η (λ) is the photoelectric transformation efficiency of the first photodetector 3 and the second photodetector 4, relevant with light wavelength to be measured.

According to the ratio of the electric signal of the first photodetector 3 and the second photodetector 4can determine light wavelength value λ to be measured:

$\frac{V_1}{V_2}=\frac{T\left(\mathrm{\λ}\right)}{1-T\left(\mathrm{\λ}\right)}---\left(1\right)$

Due to transmissivity T (λ) monotone variation within the scope of whole service band of light splitting piece 2, and be known quantity, therefore calculative determination light wavelength value to be measured λ easily.

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

$P_0=\frac{V_1}{\mathrm{\η}\left(\mathrm{\λ}\right)T\left(\mathrm{\λ}\right)}=\frac{V_2}{\mathrm{\η}\left(\mathrm{\λ}\right)(1-T\left(\mathrm{\λ}\right))}=\frac{V_1+V_2}{\mathrm{\η}\left(\mathrm{\λ}\right)}---\left(2\right)$

Embodiment 2

The structure of the present embodiment is identical with enforcement 1, and difference is selected optical filter at light splitting piece 2.This light splitting piece 2 adopts optically coated mode to realize, and can realize the transmission spectrum with wavelength monotone variation by optimizing thicknesses of layers and the number of plies.The 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, wavelength band internal transmission factor reduces with wavelength linear, transmission change rate is 0.8%/nm, distinguishable rate goes out to be less than the wavelength variations of 0.2nm, and the signal wavelength that is applicable to dense wave division multipurpose DWDM Networks of Fiber Communications is surveyed (the about 0.8nm in signal wavelength interval).

Claims (3)

1. can measure the photoelectric measuring device of power and wavelength for one kind simultaneously, comprise adapter and signal processing circuit, after described adapter, be provided with light splitting piece, the first photodetector and the second photodetector, the first described photodetector is connected with described signal processing circuit with the second described photodetector, 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 wavelength monotone variation, the first described photodetector and the second described photodetector have identical photoelectric transformation efficiency, 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 after described light splitting piece light splitting until photometry inciding on described light splitting piece enters the first described photodetector, reflected light after light splitting enters the second described photodetector.

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

3. a kind of photoelectric measuring device that can simultaneously measure power and wavelength 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 SC type adapter conventional in optical communication.