CN211556422U

CN211556422U - Circuit for adjusting constant output of optical power of coaxial laser

Info

Publication number: CN211556422U
Application number: CN201821359906.2U
Authority: CN
Inventors: 柴嵘; 郑新源
Original assignee: Zhejiang University of Media and Communications
Current assignee: Zhejiang University of Media and Communications
Priority date: 2018-08-22
Filing date: 2018-08-22
Publication date: 2020-09-22
Anticipated expiration: 2028-08-22

Abstract

The utility model discloses a circuit for adjusting the constant output of the optical power of a coaxial laser. The utility model discloses adjust the circuit of the invariable output of coaxial laser luminous power, include: the laser comprises a PD (photo diode) which is used for detecting the optical power output by the laser; the adjustable potentiometer is used for adjusting reference light power reference voltage; the operational amplifier is used for reducing the output voltage through a negative feedback loop when the light power detected by the PD is larger than the reference light power reference voltage; when the light power detected by the PD is smaller than the reference light power reference voltage, the operational amplifier increases the output voltage through a negative feedback loop. The utility model discloses a this negative feedback circuit realizes the invariable output of coaxial laser luminous power, reduces the transmission luminous power fluctuation, improves cable television optical network transmission stability.

Description

Circuit for adjusting constant output of optical power of coaxial laser

Technical Field

The utility model belongs to the technical field of optical communication, especially, relate to a circuit that is used for cable television's the invariable output of regulation coaxial laser luminous power.

Background

At present, the situation that optical access and copper withdrawal are trended in the improvement of a cable television bidirectional network is great, the transmission distance of an optical network is longer and longer, and more optical devices are involved. The output optical power of the coaxial laser applied to the cable television optical network is easily influenced by factors such as environmental temperature change, device aging and the like, the generated optical power changes up and down, and the stable transmission of the cable television bidirectional optical signal is influenced.

An optical fiber access type television set disclosed in the utility model with the publication number of CN201263185Y comprises a television set high-frequency tuning circuit, wherein the input end of the high-frequency tuning circuit is connected with an optical signal receiving module; the optical signal receiving module comprises an optical/electrical converter, an attenuator, an equalizer and an amplifying circuit, wherein the optical/electrical converter is connected with the attenuator, the attenuator is connected with the equalizer, and the equalizer is connected with the amplifying circuit. The utility model discloses reserved many signal channel interfaces, proper configuration just can reverse passback access function, conveniently adapts to the access configuration of systems such as ethernet coaxial cable's transmission technology EOC, ethernet passive optical network EPON. The solution of the patent still cannot make the optical signal of the cable television output stably.

Therefore, how to make the stable transmission of the bidirectional optical signal of the cable television become the problem to be solved by the utility model.

The above is only for the purpose of assisting understanding of the technical solutions of the present invention, and does not represent an admission that the above is the prior art.

Disclosure of Invention

To the above-mentioned technical problem that prior art exists, the utility model provides an adjust the invariable circuit of output of coaxial laser luminous power to solve above-mentioned problem.

In order to achieve the technical purpose, the utility model adopts the following technical proposal:

a circuit for regulating the optical power constant output of a coaxial laser, comprising:

a laser including a PD for detecting an amount of optical power output by the laser;

the adjustable potentiometer is used for adjusting reference light power reference voltage;

the operational amplifier is used for reducing the output voltage through a negative feedback loop when the optical power detected by the PD is larger than the reference optical power reference voltage; when the light power detected by the PD is smaller than the reference light power reference voltage, the operational amplifier increases the output voltage through a negative feedback loop.

As a preferred aspect of the present invention, the operational amplifier adjusts the output voltage according to the voltage of the non-inverting input terminal and through the negative feedback loop.

As a preference of the present invention, the circuit further includes: and the triode is connected with the operational amplifier.

As the utility model discloses a preferably, when operational amplifier makes output voltage reduce through negative feedback loop, the drive passes through the electric current of triode diminishes, arouses LD's bias current diminishes in the laser, makes LD output optical power diminish.

As the utility model discloses a preferred, when operational amplifier makes output voltage increase through negative feedback loop, the drive passes through the current grow of triode arouses LD's bias current grow in the laser instrument makes LD output optical power grow.

Preferably, the laser is a BLLD series laser.

Preferably, the operational amplifier is an LM358 type chip.

As the utility model discloses a preferred, the triode adopts MMBT3904 type triode.

The utility model provides a technical scheme can include following beneficial effect:

the utility model discloses a negative feedback circuit realizes the invariable output of coaxial laser luminous power, reduces the transmission luminous power fluctuation, improves cable television optical network transmission stability.

Drawings

Fig. 1 is a circuit structure diagram for adjusting the optical power constant output of the coaxial laser according to embodiment 1 of the present invention.

Detailed Description

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. The present invention may, however, be embodied in many different forms and should not be construed as limited to the specific embodiments set forth herein. Rather, these embodiments are provided to convey the scope of the invention to those skilled in the art.

Unless otherwise defined, terms (including technical and scientific terms) used herein should be understood to have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Moreover, it will be understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Example 1

The technical solution of the present invention will be described in detail with reference to the accompanying drawings.

The embodiment provides a circuit for adjusting the optical power constant output of a coaxial laser, as shown in fig. 1, including: the circuit comprises resistors R1-R7, a capacitor C1, an inductor L1, an adjustable potentiometer RP1, a triode V1, a laser N1 and an operational amplifier N2, wherein the specific operation process of the scheme is as follows:

as shown in fig. 1, a circuit for adjusting the optical power constant output of a coaxial laser preferably includes 7 resistors R1 to R7, a capacitor C1, an inductor L1, an adjustable potentiometer RP1, a triode V1, a laser N1, and an operational amplifier N2.

The laser N1 is connected with an operational amplifier N2; the adjustable potentiometer RP1 is connected with the operational amplifier N2; operational amplifier N2 is connected to transistor V1.

The working process of the invention is as follows:

the PD in laser N1 is used to detect the amount of output optical power of laser N1.

The adjustable potentiometer RP1 is used to adjust the reference optical power reference voltage.

When the LD output light power in the laser N1 becomes larger than the reference light power, that is, the PD detection voltage in the laser N1 becomes correspondingly high, the operational amplifier N2 circuit pin 7 output voltage becomes low against the reference voltage input to pin 5 in the operational amplifier N2.

When the output voltage of the operational amplifier N2 is lowered by the negative feedback loop, that is, the base voltage of the transistor V1 is lowered, the current driving the transistor V1 is reduced, the bias current of the LD in the laser N1 is reduced, and the output optical power of the LD is reduced and approaches the reference optical power.

Similarly, when the output light power of the LD of the laser N1 becomes smaller than the reference light power, the bias current of the LD in the laser N1 is increased by the negative feedback loop, and the output light power of the LD is increased and approaches the reference light power.

The laser N1 is BLLD series laser from Xiamen Belley company, the operational amplifier N2 is LM358 type chip from National Semiconductor company, and the triode V1 is MMBT3904 type triode from Motorola company.

The devices involved in the circuit are low in cost, the control precision of the realized constant output optical power can well meet the transmission application of the cable television optical network, and the circuit has practicability.

In summary, the circuit for adjusting the optical power constant output of the coaxial laser provided in this embodiment realizes the corresponding optical power constant output by negative feedback loop control according to the reference voltage of the 5 th pin of the input operational amplifier N2.

Other embodiments of the present disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the disclosure following, in general, the principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

Claims

1. A circuit for regulating the optical power constant output of a coaxial laser, comprising:

2. The circuit for adjusting optical power constant output of coaxial laser as claimed in claim 1, wherein the operational amplifier adjusts the output voltage according to the voltage of the non-inverting input terminal through a negative feedback loop.

3. The circuit for regulating optical power constant output of a coaxial laser as set forth in claim 1, further comprising: and the triode is connected with the operational amplifier.

4. The circuit of claim 3, wherein when the operational amplifier reduces the output voltage through a negative feedback loop, the current driving the transistor is reduced, which causes the bias current of the LD in the laser to be reduced, so that the output optical power of the LD is reduced.

5. The circuit of claim 3, wherein when the operational amplifier increases the output voltage through a negative feedback loop, the current driving the transistor increases, which causes the bias current of the LD in the laser to increase, and the output optical power of the LD increases.

6. The circuit for regulating the optical power constant output of a coaxial laser as claimed in claim 1, wherein the laser is a BLLD series laser.

7. The circuit for regulating the optical power constant output of a coaxial laser as claimed in claim 1, wherein the operational amplifier is made of an LM358 type chip.

8. The circuit for regulating the optical power constant output of a coaxial laser as claimed in claim 3, wherein the triode is a MMBT3904 type triode.