CN111933719A - High-power low-noise photoelectric detector - Google Patents

Abstract

The invention discloses a high-power and low-noise photoelectric detector, which is characterized in that the photoelectric detector comprises a base, a casing, a circuit board, a power interface, a filter capacitor, an operational amplifier, a precision resistor, a photodiode and a signal output interface , filter capacitors, operational amplifiers, photodiodes and precision resistors are arranged on the circuit board, the power interface and signal output interface are arranged on the circuit board; the housing cover is installed on the base to form an accommodation space, and two holes are opened on the side; The upper end of the casing is also provided with a light inlet, and the light inlet is provided with a protective cover; the circuit board is arranged in the accommodating space, and a temperature control system with a semiconductor refrigeration chip combined with a precision resistor is added to the bottom of the photodiode with a large photosensitive surface. , to achieve a constant low temperature working environment, effectively reduce the thermal noise component caused by the photodetector in the detection of high-power laser signals, and improve the working stability and accuracy of the test signal.

Description

A high-power low-noise photodetector

【Technical field】

The invention relates to the field of photoelectric detection, in particular to a high-power and low-noise photoelectric detector.

【Background technique】

Because most of the current photodetectors are realized by ordinary photodiodes combined with circuit amplifiers, there are mainly the following shortcomings:

①The area of the photosensitive surface of ordinary photodiodes is limited, and under the same damage condition of optical power density, the amount of optical power it can withstand is limited, and it is difficult to achieve effective detection of high-power laser signals;

②Ordinary photodiodes do not have cooling capacity, so in the working process, especially in high-power detection, it is easy to cause obvious thermal noise and interfere with the test results;

③Using a circuit amplifier to increase the load resistance can reduce the thermal noise to a certain extent, but at the same time improve the photoelectric conversion coefficient, which leads to a decrease in the optical power corresponding to the saturated output voltage under the same power supply conditions, which means reducing the detection optical power. the cost;

[Content of the invention]

To solve the above problems, a high-power and low-noise photodetector is proposed;

A high-power and low-noise photodetector, characterized in that the photodetector includes a base, a casing, a circuit board, a power interface, a filter capacitor, an operational amplifier, a precision resistor, a photodiode and a signal output interface;

The circuit board is provided with a filter capacitor, an operational amplifier, a photodiode and a precision resistor;

The bottom of the photodiode is also provided with a semiconductor refrigeration chip;

The power interface and the signal output interface are arranged on the circuit board;

The housing cover is mounted on the base to form an accommodating space, and two holes are opened on the side;

The upper end of the casing is further provided with a light inlet, and a protective cover is arranged on the light inlet;

The circuit board is arranged in the accommodating space; the power interface and the signal output interface protrude outward through the hole.

Further, the photodiode is a photodiode with a large photosensitive surface, the photosensitive surface is 3mm ² to 5mm ² , and a thermistor is integrated inside.

Further, the shell is provided with a snap button, the base is provided with a snap groove, and the two are matched and connected, and the shell and the base are also provided with threaded holes, which are fixed by screws.

Further, the operational amplifier is a low noise operational amplifier.

Further, the detector is also provided with a battery system.

The invention adopts the novel large photosensitive surface photodiode as the basis to prepare a novel high-power and low-noise photodetector, and on this basis, realizes the detection of a laser signal exceeding 100 mW without any filtering or attenuation measures;

The invention realizes a constant low temperature working environment by adding a temperature control system of a semiconductor refrigerating sheet combined with a precision resistor at the bottom of the photodiode with a large photosensitive surface, effectively reduces the thermal noise component caused by the photodetector in the detection of a high-power laser signal, and improves the test performance. The working stability and accuracy of the signal;

The invention adopts a low-noise operational amplifier combined with a precision resistor with a lower resistance value to realize the amplification of the electrical signal generated by the photodiode, and at the same time, a temperature control system of a semiconductor refrigeration chip combined with a precision resistor is introduced on the back of the circuit board to realize a constant low temperature working environment. , reduce the thermal noise component caused by reducing the resistance value resistance;

The invention also provides a battery system for supplying power to the entire photoelectric detector, reducing the interference influence of power supply noise, and effectively increasing the laser power corresponding to the saturated output voltage.

【Description of drawings】

Fig. 1 is the external structure schematic diagram of the present invention;

FIG. 2 is a schematic diagram of the main board structure of the present invention;

【Detailed ways】

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

A high-power and low-noise photodetector, characterized in that the photodetector includes a base 1, a housing 2, a circuit board 3, a power interface 4, a filter capacitor 5, an operational amplifier 6, a precision resistor 7, and a photodiode 8 and the signal output interface 9; the circuit board 2 is provided with a filter capacitor 4, an operational amplifier 6, a photodiode 8 and a precision resistor 7; the bottom of the photodiode 8 is also provided with a semiconductor refrigeration chip; the power interface 4 and the signal output interface 9 are arranged on the circuit The shell 1 is covered on the base 2 to form an accommodating space, and two holes are opened on the side; the shell is provided with a buckle, wherein the base is provided with a slot, and the shell and the base are also provided with threads The holes are fixed by screws, and the circuit board 3 is arranged in the accommodating space; the power interface 3 and the signal output interface 4 protrude outward through the holes, wherein the photodiode is a photodiode with a large photosensitive surface, and the photosensitive surface is 3mm ² ~ 5mm ^2. The thermistor is integrated inside, the operational amplifier is a low-noise operational amplifier, and the detector is also provided with a battery system; the upper end of the casing is also provided with a light inlet, and the light inlet is provided with a protective cover 10;

Connect the power interface 3 to the external power supply, so that the photodetector is in a ready state, and connect the output signal interface 9 to the test equipment, such as a spectrum analyzer, acquisition card or oscilloscope, to achieve effective signal acquisition, and then use the optical power. The meter tests the power of the optical signal to be measured and records it. If it exceeds the test range, attenuation operation is required. Finally, the protective cover 10 of the light inlet of the photodetector is opened, and the test laser signal is connected and fixed to the designated position. The photosensitive surface of the photodiode 8 can effectively receive the laser signal to be measured.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within the range.

Claims (5)

1. A high-power low-noise photoelectric detector is characterized by comprising a base, a shell, a circuit board, a power interface, a filter capacitor, an operational amplifier, a precision resistor, a photoelectric diode and a signal output interface;

the circuit board is provided with a filter capacitor, an operational amplifier, a photodiode and a precision resistor;

the bottom of the photodiode is also provided with a semiconductor refrigerating sheet;

the power supply interface and the signal output interface are arranged on the circuit board;

the shell is covered on the base to form an accommodating space, and two holes are formed in the side edge of the shell;

the upper end of the shell is also provided with a light inlet, and a protective cover is arranged on the light inlet;

the circuit board is arranged in the accommodating space; the power interface and the signal output interface extend outwards through the holes.

2. A high power, low noise photodetector according to claim 1, wherein: the photodiode is a large-photosurface photodiode with a photosurface of 3mm²～5mm²And a thermistor is integrated inside the heat-sensitive element.

3. A high power, low noise photodetector according to claim 1, wherein: the shell is provided with a buckle, the base is provided with a clamping groove, the shell and the base are connected in a matched mode, and the shell and the base are both provided with threaded holes and are fixed through screws.

4. A high power, low noise photodetector according to claim 1, wherein: the operational amplifier is a low noise operational amplifier.

5. A high power, low noise photodetector according to claim 1, wherein: and the detector is also provided with a battery system.

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