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Optical fiber silicon microphone system based on phase carrier modulation

A phase carrier, micro-microphone technology, used in sensors, lasers, phonon exciters, etc.

Inactive Publication Date: 2011-03-16
INST OF ACOUSTICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method of realizing light sensing by modulating the intensity of light has the advantage of being relatively simple and has relatively low requirements for light sources and electronic systems. For example, general light-emitting diodes (LEDs) can meet the requirements, but such systems also have some shortcomings. :
[0007]2) Since the sensitivity of the sensor using light intensity modulation is lower than that of other modulation methods such as optical phase modulation, the dynamic range is also smaller than that of the optical phase modulation system. Therefore, in the case of high requirements on sensitivity and dynamic range, the sensing technology with light intensity modulation cannot meet the requirements

Method used

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  • Optical fiber silicon microphone system based on phase carrier modulation
  • Optical fiber silicon microphone system based on phase carrier modulation
  • Optical fiber silicon microphone system based on phase carrier modulation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032]The working principle of the present invention is like this: described optical fiber MEMS microphone probe 500 at least comprises a gradient lens (also called self-focusing lens) and a MEMS vibrating membrane with reflective area (or claims reflective spot), the exit of gradient lens The end face and the reflective area (or reflective spot) on the MEMS diaphragm are placed in parallel to form a laser Fizeau interference cavity. The gradient lens is used as a collimating lens for outgoing light and a converging lens for reflecting light from the reflective area (or called reflective spot) on the MEMS vibrating membrane. The outgoing end surface of the gradient lens is coated with a reflective film to reflect a part of the incident light as the reference arm (that is, the path that the optical signal does not contain the sensing information) optical signal, while the signal arm (that is, the optical signal that contains the sensing information) The length of the path trave...

Embodiment 2

[0041] The phase carrier modulated laser light source 100 includes a signal source 105, an operational amplifier A1, a transistor Q1, a DFB laser L1, a zener diode D1, and several resistors and capacitors. The negative input terminal of the amplifier A1 is connected to the feedback signal, and the amplification factor can be determined by the ratio of the resistance values ​​of the feedback resistor R6 and the grounding resistor R5.

[0042] The DC voltage source generates an adjustable DC voltage through the variable resistor R1, and the signal source 105 generates an AC modulation signal, and the DC voltage and an AC modulation signal pass through the DC branch resistor R2, the AC branch resistor R3, the grounding resistor The adding circuit composed of R4 is superimposed together, and then connected to the input terminal of the operational amplifier A1. Among them, the resistance value range of the grounding resistance R4 is 10 to 100 times that of the DC branch resistance ...

Embodiment 3

[0047] In this embodiment, the optical fiber MEMS microphone probe 500 includes a gradient lens 506, a pigtail 508, a Fizeau cavity support 505 and a MEMS sensor chip. The gradient lens 506 is connected to the transmission fiber 400 through the pigtail 508 . The MEMS sensor chip described therein consists of a bulk etching mask 501 , a silicon substrate 502 , a vibrating membrane 503 and a reflective film region 504 fabricated on the vibrating membrane 503 .

[0048] The reflective film area 504 is used to reflect the optical signal from the gradient lens 506, and the reflected optical signal is coupled into the optical fiber through the gradient lens 506 as a sensing signal from the signal arm.

[0049] The Fizeau interference cavity support 505 is generally made of non-metallic material (such as plexiglass, polyvinyl chloride material, ceramics, glass, etc.), and is used to fix the MEMS sensor chip and the gradient lens 506, so that The exit end surface 507 is placed parall...

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Abstract

This invention relates to a fiber silicon microphone system based on phase carrier modulation including a laser source, fibers, a fiber coupler, a microphone probe and a photoelectric detector, in which, the laser source is one of phase carrier modulation, the fiber coupler is connected with the laser source by input fiber and connected with the probe by transmission fiber and connected with the detector by output fiber, said probe includes a gradient lens and a vibration film with a reflection region, and the exit end face of the gradient lens is placed parallel to the reflection region of the vibration film to constitute a laser Fizeau interference cavity.

Description

technical field [0001] The invention relates to the technical field of micro-electromechanical devices, in particular, the invention relates to a fiber silicon micro-microphone system based on phase carrier modulation. Background technique [0002] Microphone, also known as Microphone (transliteration of Microphone), is a device that converts voice signals into electrical signals, and it is widely used in our lives. Corresponding to different application requirements and occasions, a variety of microphones have emerged, such as electret microphones, silicon microcapacitor microphones, and fiber optic microphones. [0003] Electret microphones and silicon microcapacitor microphones are the most commonly used microphones in consumer electronics products, such as mobile phones, tape recorders, earphones, computers and PDAs (Personal Digital Assistants), etc. They are all sound-to-electricity conversion devices, that is, Convert the change of sound wave sound pressure into the ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04R23/00H01S3/00
Inventor 乔东海宫铭举田静王孟姣张迪
Owner INST OF ACOUSTICS CHINESE ACAD OF SCI
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