CN115824407A

CN115824407A - Integrated spectral measurement device capable of working in ultra-wide temperature range

Info

Publication number: CN115824407A
Application number: CN202211448812.3A
Authority: CN
Inventors: 李昂
Original assignee: Nanjing University of Aeronautics and Astronautics
Current assignee: Nanjing University of Aeronautics and Astronautics
Priority date: 2022-11-18
Filing date: 2022-11-18
Publication date: 2023-03-21

Abstract

The invention discloses an integrated spectrum measuring device capable of working in an ultra-wide temperature range, and belongs to the technical field of measurement and testing. The device comprises 1 temperature sensor, 1xM multi-path power beam splitter, M broadband spectrum shapers with different spectral responses and M photodetectors. The temperature sensor is used for sensing the working environment temperature of the device, the power beam splitter is used for dividing the signal to be measured into M parts, each part of the signal to be measured passes through 1 broadband spectrum shaper and then is converted into current by 1 photoelectric detector, and the current output by the M detectors can be used for reconstructing a spectrum after being processed by a post algorithm. Before the spectrum measuring device is put into use, the responses of the M broadband spectrum shapers at different temperatures are recorded in advance, and spectrum reconstruction at different temperatures can be realized by reading the real-time working temperature and bringing the responses of the M broadband spectrum shapers at corresponding temperatures into a processing algorithm in work, so that the spectrum measuring device works in an ultra-wide temperature range.

Description

Integrated spectral measurement device capable of working in ultra-wide temperature range

Technical Field

The invention relates to a spectrum measurement technology, in particular discloses an integrated spectrum measurement device capable of working in an ultra-wide temperature range, and belongs to the technical field of measurement and testing.

Background

To detect information about the target spectrum, spectrometers have come to work, which can recover any unknown spectrum that is input. The spectrometer is widely applied to the fields of communication, materials science, astronomy, geography science, remote sensing and the like. With the development of the internet of things and intelligent equipment, an integrated spectrometer capable of reconstructing a spectrum through single measurement is urgently needed, such as intelligent wearable equipment, portable medical equipment, unmanned aerial vehicle remote sensing and the like. The existing integrated spectrometer mostly adopts a narrow-band light splitting type, and the structure is shown in fig. 1, namely, a series of narrow-band spectrum devices working in different wavelength ranges (except for a narrow spectral range, the transmission functions of other working wavelengths are all 0) are utilized to extract different wavelength components of a signal spectrum to be measured and measure the components separately. The spectral reconstruction can be achieved by simply stitching these measurements. Common narrow-band spectral devices include dispersive gratings, narrow-band filters, and the like. However, the integrated spectrometer generally has a temperature sensitivity problem, that is, a shift of a spectral transfer function of the integrated photonic device may be caused by a change of an external temperature, and for a narrow-band spectral device, the shift may cause a normal operating wavelength range transfer function of the narrow-band spectral device to become 0, thereby causing a loss of spectral information of the band. Therefore, integrated spectrometers typically require additional temperature control devices to keep their operating temperature constant, but the additional temperature control devices result in additional hardware costs and system power consumption, and increase the duration of the spectral measurements.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming the defects in the prior art, provides an integrated spectrum measuring device capable of working in an ultra-wide temperature range, adopts a series of broadband spectrum devices as core devices, achieves the aim of realizing the invention that the integrated spectrum measuring device without an additional temperature control device can also work in the ultra-wide temperature range, and solves the technical problem that the hardware cost and the power consumption of a system are increased when the additional temperature control device is introduced into the prior integrated spectrometer to overcome the defect of temperature drift of a transmission function.

The invention specifically adopts the following technical scheme to solve the technical problems:

an integrated spectral measurement device comprises 1 temperature sensor, 1xM power beam splitter, M broadband spectrum shapers, M photodetectors and 1 signal processing unit. The temperature sensor is used for acquiring external temperature and feeding back the external temperature to the signal processing unit; the 1xM power beam splitter is used for uniformly dividing a signal to be detected into M parts and correspondingly passing through M broadband spectrum shapers one by one, the transmission coefficient of each broadband spectrum shaper is not 0 in a wider spectral range and has higher randomness, the transmission functions of all broadband spectrum shapers cover the spectral range of an optical signal to be detected, the transmission functions of any two broadband spectrum shapers are different, namely have lower linear correlation, the transmission functions of the spectrum shapers at all temperatures in the range of 10-80 degrees are recorded in advance, and each broadband spectrum shaper samples one part of signal to be detected and then outputs a spectrum sampling signal with corresponding bandwidth; the output ends of the M broadband spectrum shapers are connected with the M photoelectric detectors, each photoelectric detector converts a received spectrum sampling signal into current and outputs the current to the signal processing unit, the signal processing unit extracts a transmission function of the broadband spectrum shaper array at the corresponding working temperature by combining the actually measured working temperature, and the signal spectrum to be measured can be reconstructed after the response of the broadband spectrum shaper array at the working temperature is processed by an algorithm.

Compared with the prior art, the technical scheme of the invention has the following beneficial effects: the integrated spectrum measuring device based on M broadband spectrum shapers can reconstruct the unknown spectrum of a signal through single measurement, can work in an ultra-wide temperature range, does not need an additional temperature controller, does not generate additional power consumption and hardware cost, and greatly expands the use scene of the integrated spectrometer.

Drawings

Fig. 1 is a schematic structural principle diagram of a conventional integrated spectral measurement device based on narrow-band spectroscopy.

Fig. 2 is a schematic diagram of the structural principle of the integrated spectrum measuring device capable of working in the ultra-wide temperature range according to the present invention.

Figure 3 is a simulation result of the transfer function of the broadband spectrum shaper at different temperatures.

Fig. 4 shows simulation results of the spectrum reconstructed by the integrated spectrum measuring device of the present invention at different temperatures.

Detailed Description

Aiming at the problem that the existing narrow-band light-splitting integrated spectrometer can only work at a specific temperature, the invention adopts a broadband spectrum shaper array with a non-0 transmission coefficient in a wider spectral range to sample a signal to be measured in a full spectral range. Recording the transmission functions of the broadband spectrum shaper array at all temperatures within a certain temperature range in advance, sensing the real-time working temperature through a temperature sensor, extracting the transmission functions of the broadband spectrum shaper at the corresponding working temperature, and performing spectrum reconstruction by adopting a specific algorithm.

an integrated spectral measurement device comprises 1 temperature sensor, 1xM power beam splitter, M broadband spectrum shapers, M photodetectors and 1 signal processing unit. The temperature sensor is used for acquiring external temperature and feeding back the external temperature to the signal processing unit; the 1xM power beam splitter is used for uniformly dividing a signal to be detected into M parts, the M parts of the signal to be detected pass through M broadband spectrum shapers in a one-to-one correspondence mode, the transmission coefficient of each broadband spectrum shaper is not 0 in a wider spectral range and has higher randomness, the transmission functions of any two broadband spectrum shapers are different, namely, the linear correlation is lower, and the transmission functions of the broadband spectrum shaper array at all temperatures in a certain temperature range are recorded in advance; the output ends of the M broadband spectrum shapers are connected with the M photoelectric detectors, the output of the photoelectric detectors is sent to the signal processing unit, the transmission function of the corresponding broadband spectrum shaper array at the temperature is extracted by combining the existing working temperature, and the spectrum of the signal to be measured can be reconstructed after algorithm processing.

Preferably, the broadband spectrum shaper employed may be based on a cascaded configuration of multiple asymmetric mach-zehnder interferometers.

For the public understanding, the following is a detailed description of the technical solution of the present invention:

the structure of the integrated spectrum measuring device provided by the invention is shown in fig. 2, and comprises 1 temperature sensor, 1xM power beam splitter, M broadband spectrum shapers, M photoelectric detectors and 1 signal processing unit. When spectral measurement is carried out, optical signals to be measured are uniformly distributed to M wide-spectrum shaping devices through a 1xM power beam splitter, M optical signal outputs are generated, then, the M photoelectric detectors are used for carrying out one-to-one photoelectric detection on the optical signals output by the M photoelectric detectors, and then, the optical signals are converted into electric signals, wherein the expression is as follows:

I _1×M ＝φ _1×N T _N×M /n

wherein, I _1×M ＝[I ₁ ，I ₂ ，……，I _M ]，I ₁ ，I ₂ ，…，I _M Respectively showing the detection results of the 1 st to Mth photodetectors; n is a normalized coefficient obtained through calibration; phi is a _1×N ＝[φ _λ1 ，φ _λ2 ，……，φ _λN ]The spectrum of the optical signal to be measured, N is the ratio of the bandwidth and the precision of the spectrometer, and can be regarded as N unknowns; t is a unit of _N×M ＝[T ₁ (λ)，T ₂ (λ)，……，T _M (in)]Is the transfer function, T, of said M broadband spectral shapers _i (λ)＝[T _{i_λ1} ，T _{i_λ2} ，……，T _{i_λN} ] ^T For the spectral transfer function of the ith broadband spectral shaper, i =1,2, \8230; \8230, M, can be measured in advance. Because the transmission function heights of the M broadband spectrum shapers are different, the equation set can be solved through a specific algorithm, so that N unknown values are obtained, and spectrum reconstruction is realized.

When the ambient temperature changes, the integrated photonic device transfer function can be caused to drift. The traditional integrated spectrum measuring device is based on narrow-band light splitting devices, the transmission function of each device is not 0 in the vicinity of narrow specific wavelength, and the rest spectrum intervals are 0. When the transfer function drifts, the transfer function of the device at the original working wavelength becomes 0, and the spectrum sampling information near the wavelength is lost, so that the traditional integrated spectrum measuring device is generally provided with a temperature control device to fix the working temperature, the additional hardware cost and the use power consumption are introduced, and the use scene and the application range of the integrated spectrum measuring device are severely restricted. The invention adopts a series of broadband spectrum shapers with different transmission functions as spectrum samplers, each device has a transmission function which is not 0 in a wider range, and the purpose of spectrum reconstruction is achieved by solving a linear equation set. When temperature changes cause the transfer function of the broadband spectrum shaper to drift, it is inThere is still a transfer function other than 0 in the operating spectral range, so spectral sampling information is not lost. The transmission function of each broadband spectrum shaper at different temperatures is recorded in advance, the working temperature of the integrated spectrum measuring device is sensed in real time by adopting a temperature sensor, and the transmission function, namely T, of the corresponding broadband spectrum shaper at the temperature is extracted when a linear equation system is solved _NxM The system of equations can still be solved accurately to achieve spectral reconstruction.

Fig. 3 shows the change of the transmission function of the broadband spectrum shaper at different temperatures, and it can be seen that although the transmission function is shifted due to the temperature, the transmission coefficients are not 0 at each wavelength point, and the linear equation system is still valid, but the coefficients of the unknown numbers are changed. The transmission functions of the broadband spectrum shaper array at various temperatures are recorded in advance, and the corresponding broadband spectrum shaper transmission functions are extracted according to the real-time working temperature during signal processing, so that the equation set can be accurately solved and the spectrum can be reconstructed. The simulation results of spectrum reconstruction at different temperatures are shown in fig. 4, and the spectrum reconstructed by the integrated spectrum measuring device provided by the invention at the working temperature of 20 degrees is basically consistent with the spectrum reconstructed at the working temperature of 80 degrees, which represents that the integrated spectrum measuring device provided by the invention can work in an ultra-wide temperature range of 10 degrees to 80 degrees without an additional temperature control device.

The above embodiments are merely illustrative of the present invention and do not limit the scope of the invention, and those skilled in the art may partially modify the invention and any equivalent substitution in any form that meets the gist of the invention falls within the scope of the invention.

Claims

1. An integrated spectral measurement device operable over an ultra-wide temperature range, comprising:

the power beam splitter is provided with M paths of outputs and is used for splitting the optical signal to be measured into M paths of optical signals;

each broadband spectrum shaper receives one path of optical signal output by the power beam splitter and samples the optical signal according to a transmission function of the broadband spectrum shaper, and each broadband spectrum shaper outputs the sampled optical signal;

each photoelectric detector receives a spectrum signal output by one broadband spectrum shaper, and converts the received spectrum signal into a current signal and outputs the current signal; and a process for the preparation of a coating,

and the signal processing unit is used for receiving the current signals output by the M photoelectric detectors, extracting the transmission function of the broadband spectrum shaper array according to the actual working temperature and reconstructing the spectrum of the optical signal to be detected.

2. The integrated optical spectrum measurement device of claim 1, wherein the array of broadband spectrum shapers has a transfer function of each broadband spectrum shaper within a spectral interval of the respective operating wavelength that is different from 0, wherein the transfer functions of any two broadband spectrum shapers are different, and wherein the transfer functions of all broadband spectrum shapers cover the spectral range of the optical signal to be measured.

3. The integrated spectral measurement device of claim 1, wherein the signal processing unit has a pre-stored transfer function for the array of broadband spectrum shapers at all temperatures within a pre-determined temperature range.

4. An integrated spectroscopic measurement device operable over an ultra-wide temperature range as defined in claim 1 wherein the signal processing unit solves the system of equations I _1×M ＝φ _1×N T _N×M /n reconstruction of the spectrum of the light signal to be measured, where I _1×M ＝[I ₁ ，I ₂ ，……，I _M ]，I ₁ ，I ₂ ，…，I _M Respectively representing current signals output by the 1 st to Mth photodetectors; n is a normalized coefficient obtained through calibration; phi is a _1×N ＝[φ _λ1 ，φ _λ2 ，……，φ _λN ]For the spectrum of the optical signal to be measured, N is the integrated spectral measuring device bandThe ratio of width to precision; t is _N×M ＝[T ₁ (λ)，T ₂ (λ)，……，T _M (λ)]，T ₁ (λ),T ₂ (λ),……,T _M (λ) is a transfer function of the M broadband spectrum shapers.

5. An integrated spectroscopic measurement device operable over an ultra-wide temperature range as set forth in claim 1 wherein said actual operating temperature is obtained by a temperature sensor.