CN202998102U

CN202998102U - Optical fiber simulator for detecting best multiplication factor of avalanche photodiode

Info

Publication number: CN202998102U
Application number: CN 201220597984
Authority: CN
Inventors: 李楚元
Original assignee: Connaught Instrument (weihai) Co Ltd
Current assignee: Inno Instrument (china) Inc; INNO INSTRUMENT (WEI HAI) Inc
Priority date: 2012-11-13
Filing date: 2012-11-13
Publication date: 2013-06-12
Anticipated expiration: 2022-11-13

Abstract

The utility model discloses an optical fiber simulator for detecting the best multiplication factor of an avalanche photodiode. The optical fiber simulator is composed of an optical circulator and an attenuator, wherein the optical circulator and the attenuator are connected to form an optical path; and an optical coupler can be added in the optical path. The optical fiber simulator disclosed by the utility model can change value of the attenuator and regulate bias voltages at two ends of the avalanche photodiode (APD), so as to detect the best multiplication factor of the avalanche photodiode.

Description

A kind of optical fiber simulator for detection of the best multiplication factor of avalanche photodide

Technical field

The utility model relates to the optical fiber cable detection field, particularly for the detection field of the avalanche photodide just bias voltage of optical time domain reflectometer.

Background technology

In the Optical Cable Measurement field, the rayleigh backscattering that produces when utilizing light to transmit in optical fiber and Fresnel reflection are connected and are adopted optical time domain reflectometer (OTDR) to carry out field monitor that optical fiber connects and junction loss to measure that to estimate be effective method at present, can carry out the measurement of transmission attenuation, joint decay and the fault location etc. of fiber lengths, optical fiber.The backscatter signals power from light path that receives due to OTDR is less, therefore requiring has higher sensitivity as the photodetector of opto-electronic conversion, and avalanche photodide (hereinafter referred to as APD) its internal current under suitable bias voltage has multiplier effect, as Fig. 1, in figure, dotted line is the signal to noise ratio snr curve, solid line is the multiplication factor curve, V ₀It is still best bigoted electrical voltage point.APD can effectively amplify the signal to be detected from light path, therefore avalanche photodide is commonly used for the photodetector of OTDR.Ignoring under the temperature influence condition, the APD multiplication factor determines by bias voltage usually, if APD two ends bias voltage is too high, introduced more noises, causes signal to noise ratio bad, and in a single day voltage surpassed threshold value simultaneously, can cause that the APD pipe is breakdown.If APD two ends bias voltage is too low, can't play preferably amplification.For APD is operated under the optimum signal-noise ratio condition, need find the corresponding bias voltage that can make APD multiplication factor the best, not carry out but reach best magnification in prior art when how to make APD in OTDR detect Rayleigh scattering signal dorsad the technology accurately measured.

The utility model content

The purpose of this utility model is to provide the optical fiber simulator that can find the best multiplication factor of APD.

The method that realizes the utility model purpose is: a kind of optical fiber simulator for detection of the best multiplication factor of avalanche photodide, formed by optical circulator and attenuator, and described optical circulator and attenuator connect into light path.

This programme can come the Rayleigh scattering power attenuation dorsad of analog optical fiber near-end by regulated attenuator numerical value, and then finds the best multiplication factor of APD and corresponding bias voltage, namely finds the APD optimum signal-noise ratio.The utility model is simple in structure, and is easy to operate.

The method for optimizing of realizing the purpose of this utility model is also to comprise optical fiber in described light path.It plays the light transmission time effect that postpones in simulator.

Another method for optimizing of realizing the purpose of this utility model is, also comprises optical coupler in described light path, and described coupler is located between avalanche photodide and optical circulator.Coupler effect in described optical coupler simulation OTDR.

The use of optical coupler more corresponds to actual needs the utility model.

Description of drawings

In order to be illustrated more clearly in the utility model or technical scheme of the prior art, the below will do simple the introduction to the accompanying drawing of required use in embodiment or description of the Prior Art.Apparent pin, the accompanying drawing in the following describes is only embodiment more of the present utility model, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain according to these accompanying drawings other accompanying drawing.

Fig. 1 is APD multiplication factor and bias voltage relation curve;

The embodiment schematic diagram that Fig. 2 provides for the utility model.

Embodiment

Below in conjunction with accompanying drawing, the technical scheme in the utility model embodiment is clearly and completely described, obviously, described embodiment is only the utility model part embodiment, rather than whole embodiment.Based on the embodiment in the utility model, those of ordinary skills are not making all other embodiment that obtain under the creative work prerequisite, all belong to the scope of the utility model protection.

As shown in Figure 2, LD laser 3 Emission Lasers enter coupler 2, enter into optical circulator 12 through coupler 2, and enter through 122 mouthfuls of circulators, enter attenuator 13 through long optical fibers 11, go out to inject 121 mouthfuls of circulators by attenuator 13, and enter coupler through 122 mouthfuls of circulators, go out to enter APD4 through coupler.

LD laser 3 emission maximum luminous power laser enter APD wave detector 4 through said process.The Rayleigh scattering power attenuation dorsad of attenuator in Fig. 2 (13) analog optical fiber near-end, its value is by proximal fiber Rayleigh scattering factor decision dorsad, value by changing attenuator 13 is also regulated APD two ends bias voltage, can measure corresponding multiplication factor, and its relation as shown in Figure 1.In figure, the V0 point is the just bias electrical voltage point.Optical fiber 11 plays the light transmission time effect that postpones in simulator.

Certainly, the present embodiment is most preferred embodiment.Also the coupler 2 in the present embodiment can be saved the same purpose that can reach the power attenuation of simulation light path.

Also attenuator 13 and circulator 12 can be inserted in a shell, put again an action pane on shell.

The utility model also can be used in the light path system design, and transform the APD in Fig. 2 into other light path element this moment, detects the adaptability of light path element and light path by the value of regulated attenuator 13.

Claims

1. the optical fiber simulator for detection of the best multiplication factor of avalanche photodide, is characterized in that, be comprised of optical circulator (12) and attenuator (13), described optical circulator (12) and attenuator (13) connect into light path.

2. the optical fiber simulator for detection of the best multiplication factor of avalanche photodide according to claim 1, is characterized in that, also comprises optical fiber (11) in described light path.

3. any described optical fiber simulator for detection of the best multiplication factor of avalanche photodide according to claim 1 and 2, it is characterized in that, also comprise optical coupler (2) in described light path, described coupler (2) is located between avalanche photodide and optical circulator (12) in light path.