CN201508254U - Semiconductor reflecting type optical fiber temperature sensor and sensing device thereof - Google Patents

Abstract

The utility model discloses a semiconductor reflecting type optical fiber temperature sensor and a sensing device thereof, which belong to the technical field of temperature sensing. The technical scheme of the sensor includes that a fixed casing (11) is arranged in a protective casing (12), a conduction optical fiber (16) and a collimating casing (15) are connected in front and back at the head end of the fixed casing (11), and the tail ends of the collimating casing (15), a semiconductor chip (14), an abutted insert element (13) and the fixed casing (11) are connected in turn. The technical scheme of the sensing device includes that an output end of a light source (30) is connected with an input end of a branching unit (20), an output end of the branching unit (20) is respectively connected with a sensor (10) and a PIN photoelectric diode (40), and the PIN photoelectric diode (40), a subsequent processing circuit (50) and a microprocessor (60) are connected in turn. The structure of the semiconductor reflecting type optical fiber temperature sensor and a sensing device thereof are much simpler, the sensor is smaller and more convenient for installation, and has wider application range, lower cost, and no special requirements on wavelength of the light source, and the system is easy for compensation, and has high temperature detecting resolution.

Description

A kind of semiconductor reflection-type optical fiber temperature sensor and sensing device thereof

Technical field

The utility model belongs to the temperature sensor technology field, relates in particular to a kind of semiconductor reflection-type optical fiber temperature sensor and sensing device thereof.

Background technology

From most improvement and designs to semiconductor absorption-type fibre optic temperature sensor in the past, nearly all scheme has all adopted the similar structures of GaAs sensitive material, 850nm light source and multimode optical fiber.Mainly there is the problem of two aspects in this structure:

1, principle aspect

In order to obtain big linear temperature-measuring range, just need select the wideer light source of spectrum for use, very difficult at the 850nm wave band.Simultaneously, along with the rising of temperature, the spectral-transmission favtor of GaAs reduces gradually.Amplitude of variation in the high-temperature part transmissivity diminishes, and sensitivity descends rapidly.Therefore, the expansion of the temperature-measuring range of sensor conflicts mutually with the raising of sensitivity, makes that at last the measuring accuracy in certain temperature-measuring range is not high.

2, process structure aspect

Transmission-type absorption-type sensor/sensor two ends all are connected to optical fiber, cause being not easy in small space settling.But owing to the needs of transmission-type absorption-type measuring principle, the structure of sensor and volume are difficult to further dwindle and improve again.

Summary of the invention

The purpose of this utility model just is to overcome the shortcoming and defect that prior art exists, and a kind of semiconductor reflection-type optical fiber temperature sensor and sensing device thereof that is not subjected to the operation wavelength restriction is provided.

The purpose of this utility model is achieved in that

Under the prerequisite that ensures measurement range and precision, utilize semi-conductive thermo-optic effect, by the reflected optical power I (T) of direct detection light signal after the semiconductor material reflection, calculate dut temperature.

I(T)＝cI ₀R

In the formula, I ₀Be input optical power, c is a coupling coefficient, and R is the reflection coefficient of semiconductor material.

Through behind the photodetector, pass through amplification, filtering again, after after the A/D conversion, the input microprocessor calculates and the demonstration dut temperature.

One, semiconductor reflection-type optical fiber temperature sensor (abbreviation sensor)

This sensor comprises fixed sleeving, protective casing, holds out against plug-in unit, semiconductor wafer, collimation sleeve pipe and conduction optical fiber;

Be provided with fixed sleeving in protective casing, at the head end of fixed sleeving, conduction optical fiber is connected with collimation sleeve pipe front and back; Collimation sleeve pipe, semiconductor wafer, the tail end that holds out against plug-in unit and fixed sleeving are connected successively.

Two, semiconductor reflection-type optical fiber temperature sensing device (abbreviation sensing device)

This device is a kind of temperature sensing device based on this sensor, comprises sensor, shunt, light source, PIN photodiode, subsequent process circuit and microprocessor;

The output terminal of light source is connected with the input end of shunt; The output terminal of shunt is connected with PIN photodiode with sensor respectively;

PIN photodiode, subsequent process circuit and microprocessor are connected successively.

Compare with semiconductor absorption-type fibre optic temperature sensor, the utlity model has following advantage and good effect:

1, structure is simpler, the littler more convenient installation of sensor, and the scope of application is wider;

2, cost is cheaper, and optical source wavelength is not had specific (special) requirements

3, system is easy to compensation, thermometric resolution height.

Description of drawings

Fig. 1 is the structural representation of semiconductor reflection-type optical fiber temperature sensor;

Fig. 2 is the block diagram of semiconductor reflection-type optical fiber temperature sensing device.

Wherein:

10-sensor,

11-fixed sleeving, 12-protective casing, 13-hold out against plug-in unit,

14-semiconductor wafer, 15-collimation sleeve pipe, 16-conduction optical fiber;

20-shunt;

30-light source;

The 40-PIN photodiode.

50-subsequent process circuit;

60-microprocessor.

Embodiment

Describe in detail below in conjunction with drawings and Examples:

One, sensor

1, overall

As Fig. 1, this sensor 10 comprises fixed sleeving 11, protective casing 12, holds out against plug-in unit 13, semiconductor wafer 14, collimation sleeve pipe 15 and conduction optical fiber 16;

Be provided with fixed sleeving 11 in protective casing 12, at the head end of fixed sleeving 11, conduction optical fiber 16 is connected with collimation sleeve pipe 15 front and back; Collimation sleeve pipe 15, semiconductor wafer 14, the tail end that holds out against plug-in unit 13 and fixed sleeving 11 are connected successively.

Its principle of work is:

Because thermo-optic effect, the refractive index of semiconductor material can change along with variation of temperature, shows certain correlativity.According to fresnel formula, material is to the refractive index decision of reflection of incident light coefficient by plane of incidence both sides material.And the refractive index of air can be regarded constant as.Therefore,, can extrapolate the refractive index variable quantity of semiconductor wafer,, calculate variation of temperature, thereby reach the purpose of measuring temperature again by thermo-optic effect by measuring the converted quantity of catoptrical power.

2, functional block

1, fixed sleeving 11

Fixed sleeving 11 is a kind of insulation (plastics) long tubes; Its function is collimation sleeve pipe 15, the semiconductor wafer 14 of fixing internal and holds out against plug-in unit 13.

2, protective casing 12

Protective casing 12 is a kind of insulation (plastics) long tubes, the head end opening, and tail end has the end; Its function is a protection sensor internal structure, and plays the effect that heat is transmitted.

3, hold out against plug-in unit 13

Holding out against plug-in unit 13 is a kind of metal coil springs: its function is to tighten up semiconductor wafer 14, prevents because mechanical effect causes the variation of reflected optical power.

4, semiconductor wafer 14

Semiconductor wafer 14 is that its refractive index with certain thermo-optical coeffecient of a kind of single-sided polishing varies with temperature and the temperature-sensitive material that changes; This ready-made semiconductor material is arranged at present on the market, and mainly as laser window material and Infrared Lens, the utility model has carried out further processing and fabricating to former wafer; Its function is to cause reflection coefficient to vary with temperature and change, and is the core component of sensor.

The selection of semiconductor sensitive material: reflectivity and temperature have correlativity preferably, and simultaneously, rate of change is big as far as possible.This just requires: the refractive index-temperature coefficient of material (be the characterisitic parameter that the semiconductor material refractive index changes with temperature, also be called thermo-optical coeffecient) is big, and linear.

5, collimation sleeve pipe 15

Collimation sleeve pipe 15 is a kind of parts commonly used; Its function is fixing and the input and output of collimation conduction optical fiber 16, makes to arrive semiconductor wafer 14 front surfaces and returned as far as possible fully in the conduction optical fiber 16 by the incident optical power of its reflection.

6, conduction optical fiber 16

Conduction optical fiber 16 is a kind of parts commonly used; Its function is the light conduction.

Two, device

1, overall

As Fig. 2, this device is a kind of temperature sensing device based on this sensor, comprises sensor 10, shunt 20, light source 30, PIN photodiode 40, subsequent process circuit 50 and microprocessor 60;

The output terminal of light source 30 is connected with the input end of shunt 20; The output terminal of shunt 20 is connected with PIN photodiode 40 with sensor 10 respectively;

PIN photodiode 40, subsequent process circuit 50 and microprocessor 60 are connected successively.

Its principle of work is:

It is I that light source 30 sends luminous power ₀Light, behind shunt 20, arrive the incident optical power I of semiconductor wafer 14 in the sensor 10 ₁=C I ₀, wherein C is the beam split coefficient.Incident light arrives shunt 20 once more after semiconductor wafer 14 reflections, arrived the luminous power I of PIN photodiode 40 by following road light path ₂=CR I ₁=RC ²I ₀, wherein R is the reflection coefficient of semiconductor wafer 14.Calculate the value of R through subsequent process circuit 50 and microprocessor 60, obtain the value of n again by the relation of the refractive index n of R and semiconductor wafer 14.Relation by refractive index in the thermo-optic effect and temperature can obtain temperature value measured.

2, functional block

1, sensor 10

Sensor 10 is semiconductor reflection-type optical fiber temperature sensors described in the utility model.

2, shunt 20

Shunt 20 is a kind of shunts commonly used, and the light of light source 30 is divided into two-way, and one the tunnel is connected with sensor 10; One the tunnel is connected with PIN photodiode 40.It is that 50: 50 fiber coupler is as shunt that the utility model is selected 1 * 2 type, splitting ratio for use.

3, light source 30

Light source 30 is a kind of LASER Light Source, and it is the semiconductor laser of 1550nm that the utility model is selected centre wavelength for use.

4, PIN photodiode 40

PIN photodiode 40 is a kind of photoelectric commutators commonly used, and the utility model is selected coaxial tail fiber type PIN photodetector for use.

5, subsequent process circuit 50

Subsequent process circuit 50 is a kind of amplification, filtering and analog-to-digital circuit of comprising commonly used, and the utility model designs production voluntarily.

6, microprocessor 60;

Microprocessor 60 is a kind of microprocessors commonly used, and it is that the S3C44B0 of kernel is as microprocessor that the utility model is selected for use with ARM7TDMI.

Claims (6)

1. semiconductor reflection-type optical fiber temperature sensor is characterized in that:

This sensor (10) comprises fixed sleeving (11), protective casing (12), holds out against plug-in unit (13), semiconductor wafer (14), collimation sleeve pipe (15) and conduct optical fiber (16);

In protective casing (12), be provided with fixed sleeving (11), the head end in fixed sleeving (11), conduction optical fiber (16) is connected with collimation sleeve pipe (15) front and back; Collimation sleeve pipe (15), semiconductor wafer (14), the tail end that holds out against plug-in unit (13) and fixed sleeving (11) are connected successively.

2. by the described sensor of claim 1, it is characterized in that:

Described fixed sleeving (11) is a kind of insulation long tube.

3. by the described sensor of claim 1, it is characterized in that:

Described protective casing (12) is a kind of insulation long tube, the head end opening, and tail end has the end.

4. by the described sensor of claim 1, it is characterized in that:

Holding out against plug-in unit (13) is a kind of metal coil spring.

5. by the described sensor of claim 1, it is characterized in that:

Semiconductor wafer (14) is that its refractive index with certain thermo-optical coeffecient of a kind of single-sided polishing varies with temperature and the temperature-sensitive material that changes.

6. semiconductor reflection-type optical fiber temperature sensing device based on the described sensor of claim 1 is characterized in that:

Comprise sensor (10), shunt (20), light source (30), PIN photodiode (40), subsequent process circuit (50) and microprocessor (60);

The output terminal of light source (30) is connected with the input end of shunt (20); The output terminal of shunt (20) is connected with PIN photodiode (40) with sensor (10) respectively;

PIN photodiode (40), subsequent process circuit (50) and microprocessor (60) are connected successively;

Described subsequent process circuit (50) is a kind of amplification, filtering and analog-to-digital circuit of comprising commonly used.

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