Device and method for phase calibration of LCOS chip

Abstract

The present invention discloses a device and method for phase calibration of an LCOS chip. The device is used for calibrating the phase of the LCOS chip and includes a tunable laser, a focusing lens, a power meter, and a driving unit. The tunable laser is used to generate an optical signal with a preset wavelength. The LCOS chip is coupled in the optical path generated by the tunable laser and is used to convert the received optical signal into a reflected light. The focusing lens and the power meter are sequentially coupled in the optical path of the reflected light converted by the LCOS chip. The driving unit is electrically connected to the LCOS chip and is used to load a binary grating with a preset period on the LCOS chip, so as to calibrate the phase of the LCOS chip through the gray scale value of the binary grating. The device optical path formed by the present invention is simple, requires fewer optical elements, the calibration method is simple to operate, the power test result is intuitive and accurate by reading through the power meter, the test result can be obtained quickly, and the efficiency and accuracy of the phase calibration of the LCOS chip can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of optical communication, and particularly to an apparatus and method for phase calibration of an LCOS chip. Background Art

[0002] LCOS (Liquid Crystal on Silicon) chips have been widely used in the field of optical communication due to their advantages such as small size, low power consumption, high light energy utilization rate, high diffraction efficiency, high resolution, and high aperture ratio.

[0003] The phase modulation curve is a very important parameter of an LCOS chip, which plays a crucial role in related tests such as the isolation degree test, diffraction efficiency test, and phase jitter test of the chip in the later stage. The modulation curve of the LCOS chip is not linear, and the phase modulation amount (also called the phase modulation depth) is also unknown. In order to facilitate the later tests of the isolation degree, diffraction efficiency and other indicators of the LCOS chip, generally, the phase modulation curve of the LCOS chip will be retested and calibrated. Traditional LCOS chip phase calibration methods include the double-beam interference method, the device and optical path used are relatively complex, the calibration method is complex, and it is not intuitive enough to observe the interference fringes using a CCD camera, resulting in a large error in the observation result and low accuracy.

[0004] In view of this, how to overcome the defects of the existing technology and solve the above technical problems is a difficult problem to be solved in this technical field. Summary of the Invention

[0005] The technical problem to be solved by the present invention is that the device and optical path used in the existing LCOS chip 4 phase calibration method are complex, and the efficiency and accuracy of LCOS chip 4 calibration are low due to the lack of intuitiveness in observing interference fringes using a CCD camera.

[0006] The present invention is implemented as follows:

[0007] In a first aspect, the present invention provides an apparatus for phase calibration of an LCOS chip, the apparatus is used for calibrating the phase of the LCOS chip 4, and the apparatus includes a tunable laser 1, a focusing lens 5, a power meter 7, and a driving unit 8;

[0008] The tunable laser 1 is used for generating an optical signal with a preset wavelength;

[0009] The LCOS chip 4 is coupled in the optical path generated by the tunable laser 1 and is used for converting the received optical signal into a reflected light;

[0010] The focusing lens 5 and the power meter 7 are sequentially coupled in the optical path of the reflected light converted by the LCOS chip 4;

[0011] The driving unit 8 is electrically connected to the LCOS chip 4 and is configured to load a binary grating with a preset period on the LCOS chip 4, so as to calibrate the phase of the LCOS chip 4 through the gray-scale value of the binary grating.

[0012] Preferably, it further includes a collimator 2, a polarizer 3, and a diaphragm 6;

[0013] The collimator 2 and the polarizer 3 are sequentially coupled between the tunable laser 1 and the LCOS chip 4;

[0014] The diaphragm 6 is disposed between the focusing lens 5 and the power meter 7, and the diaphragm 6 is disposed on the rear focal plane of the focusing lens 5.

[0015] Preferably, the polarization direction of the polarizer 3 is consistent with the optical axis direction of the liquid crystal molecules inside the LCOS chip 4.

[0016] Preferably, it further includes a control unit 9, and the control unit 9 is electrically connected to the driving unit 8 to control the driving unit 8 to perform phase adjustment on the LCOS chip 4.

[0017] Preferably, a display unit is provided in the control unit 9, and the display unit is electrically connected to the power meter 7 for displaying the optical power value measured by the power meter 7.

[0018] In a second aspect, the present invention further provides a method for calibrating the phase of an LCOS chip, which is applicable to the device for calibrating the phase of an LCOS chip in the first aspect. The method includes:

[0019] Obtain an optical signal with a first preset wavelength by using the tunable laser 1, and measure the first optical power P of the optical signal at this time;

[0020] Use the driving unit 8 to sequentially load a binary grating with a preset period T on the LCOS chip 4, and use the power meter 7 to record the second optical power P corresponding to each gray scale i i , and obtain the gray-scale - insertion loss curve of the LCOS chip 4 according to the values of the first optical power P and the second optical power P i ; wherein, the gray-scale value of the first T / 2 period of the binary grating is a first preset fixed value, and the gray scale i of the second T / 2 period takes any integer from 0 to 255;

[0021] Calculate the phase modulation curve of the LCOS chip 4 according to the gray-scale - insertion loss curve of the LCOS chip 4.

[0022] Preferably, the driving unit 8 is used to sequentially load a binary grating with a preset period T on the LCOS chip 4, and the power meter 7 is used to record the second optical power P corresponding to each gray level i i , and the gray level-loss curve of the LCOS chip 4 is obtained according to the values of the first optical power P and the second optical power P i ; specifically including:

[0023] Set a first preset fixed value for the gray level value of the first T / 2 period of the LCOS chip 4;

[0024] The gray level i of the second T / 2 period of the LCOS chip 4 is traversed through 256 gray levels from 0 to 255, and the second optical power P at each gray level is recorded by the power meter 7 i ;

[0025] Calculate the difference between the first optical power P and the second optical power P at each gray level, obtain the loss corresponding to each gray level, and perform curve fitting on the gray level and the corresponding loss to obtain the gray level-loss curve of the LCOS chip 4. i

[0026] Preferably, calculating the phase modulation curve of the LCOS chip 4 specifically includes:

[0027] According to the gray level-loss curve of the LCOS chip 4 and the conversion formula between the gray level i and the phase difference , calculate the phase difference

[0028] corresponding to different gray levels i Taking the phase difference corresponding to the gray level i = 0 as the reference, calculate that the phase modulation amount corresponding to the gray level i is the difference between

[0029] and , and perform curve fitting on the gray level i and the corresponding phase modulation amount to obtain the phase modulation curve of the LCOS chip 4.

[0030]

[0031] Among them, the gray level i takes an integer from 0 to 255, represents the phase difference of the gray level i, and IL i represents the loss value of the gray level i.

[0032] ​Preferably, an optical signal with a first preset wavelength is obtained by using the tunable laser 1, and the first optical power P when the tunable laser 1 generates the first preset wavelength is measured. Specifically, it includes: adjusting the wavelength of the tunable laser 1 to the first preset wavelength, directly connecting the tunable laser 1 to the power meter 7, and measuring the first optical power P of the tunable laser 1.

[0033] The above technical solutions adopted by the present invention have the following beneficial effects compared with the prior art:

[0034] The device for LCOS chip phase calibration in the embodiment of the present invention includes a tunable laser 1, a collimator 2, a polarizer 3, an LCOS chip 4, a focusing lens 5, a diaphragm 6, a power meter 7, and a driving unit 8; and the formed device optical path is simple, requires fewer optical elements, the calibration method is easy to operate, the power test result is intuitive and accurate by reading through the power meter 7, and the test result can be obtained quickly, which can effectively improve the efficiency and accuracy of LCOS chip 4 phase calibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0036] Figure 1 It is a schematic structural diagram of a device for LCOS chip phase calibration provided by an embodiment of the present invention;

[0037] Figure 2 It is a schematic diagram of a method for LCOS chip phase calibration provided by an embodiment of the present invention;

[0038] Figure 3 It is a schematic structural diagram of a binary grating generated on an LCOS chip in a method for LCOS chip phase calibration provided by an embodiment of the present invention;

[0039] Figure 4 It is a flowchart of a method for calculating the phase modulation curve of the LCOS chip 4 in a method for LCOS chip phase calibration provided by an embodiment of the present invention;

[0040] Figure 5 It is a gray scale - insertion loss curve corresponding to a method for LCOS chip phase calibration provided by an embodiment of the present invention;

[0041] Figure 6A graph of the phase difference corresponding to the same gray level i in a method for phase calibration of an LCOS chip provided by an embodiment of the present invention;

[0042] Figure 7 A phase modulation curve of the LCOS chip corresponding to a first preset wavelength of the optical signal emitted by a tunable laser in a method for phase calibration of an LCOS chip provided by an embodiment of the present invention;

[0043] Figure 8 A flowchart of a method for obtaining a gray level - insertion loss curve in a method for phase calibration of an LCOS chip provided by an embodiment of the present invention;

[0044] Among them, the reference numerals are:

[0045] 1 - Tunable laser; 2 - Collimator; 3 - Polarizer; 4 - LCOS chip; 5 - Focusing lens; 6 - Diaphragm; 7 - Power meter; 8 - Driving unit; 9 - Control unit. Detailed implementation manners

[0046] In the description of the present invention, the orientation or positional relationship indicated by terms such as "inside", "outside", "longitudinal", "transverse", "upper", "lower", "top", "bottom", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention rather than requiring the present invention to be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0047] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0048] Embodiment 1:

[0049] An embodiment of the present invention provides a device for phase calibration of an LCOS chip, as Figure 1As shown, the device is used to calibrate the phase of an LCOS chip 4. The device includes a tunable laser 1, a focusing lens 5, a power meter 7, and a driving unit 8. The tunable laser 1 is used to generate an optical signal with a preset wavelength. The LCOS chip 4 is coupled in the optical path generated by the tunable laser 1 and is used to convert the received optical signal into a reflected light. The focusing lens 5 and the power meter 7 are sequentially coupled in the optical path of the reflected light converted by the LCOS chip 4. The driving unit 8 is electrically connected to the LCOS chip 4 and is used to load a binary grating with a preset period on the LCOS chip 4, so as to calibrate the phase of the LCOS chip 4 through the gray-scale value of the binary grating.

[0050] As Figure 1 described, the device for calibrating the phase of the LCOS chip in the embodiment of the present invention includes a tunable laser 1, an LCOS chip 4, a focusing lens 5, a power meter 7, and a driving unit 8. The tunable laser 1 generates an optical signal with a preset wavelength and transmits it to the LCOS chip 4. The LCOS chip 4 reflects the linearly polarized light to obtain a reflected diffracted light. Then, through the focusing effect of the focusing lens 5, the reflected diffracted light is focused and then transmitted to the power meter 7 to measure the optical power values of different gray scales at the preset wavelength of the tunable laser 1. Among them, the tunable laser 1 can generate optical signals with different wavelengths according to actual needs, and the preset wavelength is set according to actual conditions to obtain the phase modulation curve of the LCOS chip 4 at different wavelengths.

[0051] After the driving unit 8 gives a control voltage signal to the LCOS chip 4, a certain gray scale is set for each pixel of the LCOS chip 4. At this time, the function of the LCOS chip 4 is equivalent to that of a grating, and the LCOS chip 4 will generate a phase modulation on the incident light. The corresponding change in the phase modulation amount will cause a change in the optical power.

[0052] When the driving unit 8 gives a control voltage signal, a binary grating is loaded on the LCOS chip 4. The value of the period of the binary grating can be set according to the actual situation. Among them, the gray level in the first T / 2 period is fixed and can take any integer within 0-255. In the embodiment of the present invention, the gray level in the first T / 2 period is preferably 0, 128 or 255; the gray level value in the second T / 2 period is i, which is a variable and also takes any integer within 0-255; when different control voltage signals are given by the driving unit 8, the gray level value corresponding to the second T / 2 period is different. By traversing, the gray level i is adjusted from 0 to 255 one by one. During the adjustment process, the gray level i in the second T / 2 period takes an integer (i = 0, 1, 2,..., 255). The power values corresponding to different gray levels i are measured by the power meter 7, and the gray level-loss curve at different gray levels is obtained. Finally, the phase modulation curve of the LCOS chip 4 is obtained by using the conversion formula between the gray level and the phase difference. It should be noted that after loading the gray level in the first T / 2 period and the gray level in the second T / 2 period in the LCOS chip 4 in the embodiment of the present invention, the actual effect of the LCOS chip 4 can be understood as a binary grating. The gray level in the first T / 2 period in the binary grating is fixed, the gray level in the second T / 2 period is adjustable, and the duty cycle of both is 50%; in addition, the voltage value corresponding to the gray level of the LCOS chip 4 is set by the chip manufacturer. It can be considered that by loading different voltages, the LCOS chip 4 will present the corresponding gray level.

[0053] Since the structure of the binary grating is relatively simple and is equivalent to a special case of the stepped grating, in the embodiment of the present invention, a binary grating is loaded on the LCOS chip 4 to calibrate the phase of the LCOS chip 4. Therefore, its diffraction efficiency formula is simpler than that of other gratings with complex structures. The formula between the optical power and the phase can be simplified to the relationship mentioned later. By changing the gray level of one of the steps in the LCOS adjustment period to change the phase of the binary grating and testing the corresponding optical power, the corresponding relationship between the LCOS gray level and the phase modulation amount can be obtained.

[0054] The device for calibrating the phase of the LCOS chip in the embodiment of the present invention includes a tunable laser 1, an LCOS chip 4, a focusing lens 5, a power meter 7 and a driving unit 8; and the formed device optical path is simple, the optical elements required are few, the calibration method is easy to operate, the power test result is intuitive and accurate by reading through the power meter 7, and the test result can be obtained quickly, which can effectively improve the efficiency and accuracy of the phase calibration of the LCOS chip 4.

[0055] To elaborate on the complete solution of the embodiment of the present invention, the details of the present invention will be described in detail below. As Figure 1As shown, the embodiment of the present invention further includes a collimator 2, a polarizer 3, and a diaphragm 6; the collimator 2 and the polarizer 3 are sequentially coupled between the tunable laser 1 and the LCOS chip 4; the diaphragm 6 is disposed between the focusing lens 5 and the power meter 7, and the diaphragm 6 is disposed on the rear focal plane of the focusing lens 5.

[0056] In the device for calibrating the phase of the LCOS chip according to the embodiment of the present invention, a collimator 1, a polarizer 3, and a diaphragm 6 are further provided. After the optical signal generated by the tunable laser 1 passes through the collimator 2, a collimated parallel light beam is obtained. After the collimated parallel light beam passes through the polarizer 3, it becomes linearly polarized light and is incident on the LCOS chip 4; the LCOS chip 4 reflects the linearly polarized light to obtain reflected diffracted light, and then the reflected diffracted light is focused by the focusing lens 5. The diaphragm 6 is disposed on the rear focal plane of the focusing lens 5 and is used to block the reflected diffracted light other than the ±1 order; the power meter 7 is located at the position of the +1 order or -1 order reflected diffracted light and is used to measure the optical power values of different gray levels at this position under the tunable laser 1 with a preset wavelength. It should be noted that since the light of the ±1 order is the strongest after the light passes through the grating diffraction, it is more accurate to calculate using the insertion loss of the light of the ±1 order. Blocking the light of other orders is to avoid the influence of the light of other higher orders on the test results. In the actual setting process, preferably, the power meter 7 is located at the position of the +1 order or -1 order reflected diffracted light.

[0057] Based on the characteristics of the internal structure of the LCOS chip 4, in the process of obtaining the phase modulation curve of the LCOS chip 4, in order to avoid the influence of the optical axis direction of the liquid crystal molecules inside the LCOS chip 4 on the power value measured by the power meter 7, and further affect the calculation of the insertion loss value, resulting in inaccurate measurement of the phase modulation curve of the LCOS chip 4, the embodiment of the present invention preferably makes the polarization direction of the polarizer 3 consistent with the optical axis direction of the liquid crystal molecules inside the LCOS chip 4 to minimize the influence of the placement and setting of the device on the phase modulation curve.

[0058] To obtain the phase at different gray levels, such as Figure 1As shown in the figure, the embodiment of the present invention further includes a control unit 9, which is electrically connected to the driving unit 8 to control the driving unit 8 to perform phase adjustment on the LCOS chip 4. The control unit 9 is mainly used to control the driving unit 8. The control unit 9 controls the driving unit 8 to input different combinations of voltage signals into the LCOS chip 4, so as to realize the phase loading of the LCOS chip 4. The control unit 9 in the embodiment of the present invention can but is not limited to adopt a computer device, and the driving unit 8 can but is not limited to use a driving circuit to realize the phase loading of the LCOS chip 4. When the control unit 9 gives a control voltage to the LCOS chip 4 through the driving unit 8, the LCOS chip 4 will generate a binary grating. By adjusting the different control voltages given by the driving unit 8, the gray levels in the binary grating generated by the LCOS chip 4 and the insertion loss values measured at these gray levels will change correspondingly; based on this, when the gray level i in the second T / 2 period of the binary grating takes different values, the corresponding relationship between the required control voltage signals is used to adjust the control voltage, so that the gray levels in the second T / 2 period of the binary grating generated by the LCOS chip 4 take integers from 0 to 255 one by one for traversal, calculate the insertion loss under different gray level conditions, and then through the conversion formula between the insertion loss and the phase difference, obtain the phase difference under different gray level conditions, and then take the phase difference with a gray level of 0 as a reference to obtain the phase modulation amount of different gray levels, and obtain the phase modulation curve of the LCOS chip 4 according to the phase modulation amount; wherein, the phase modulation curve of the LCOS chip 4 is the phase modulation amount curve of the LCOS chip 4 corresponding to different gray levels. In addition, a display unit (not shown in Figure 1 is presented) is provided in the control unit 9 of the embodiment of the present invention. The display unit is electrically connected to the power meter 7 and is used to display the optical power value measured by the power meter 7. It can be understood that after the optical power value is measured by the power meter 7 in the embodiment of the present invention, the optical power reading measured by the power meter 7 is finally displayed through the display unit.

[0059] The optical path formed by the device for calibrating the phase of the LCOS chip 4 in the embodiment of the present invention is simple, with fewer optical elements required. The calibration method is easy to operate. Reading the power test result through the power meter 7 is intuitive and accurate, and the test result can be obtained quickly, which can effectively improve the efficiency and accuracy of calibrating the phase of the LCOS chip 4.

[0060] Embodiment 2:

[0061] Embodiment 2 of the present invention also proposes a method for calibrating the phase of an LCOS chip. The method is applicable to the device for calibrating the phase of an LCOS chip described in Embodiment 1, as Figure 2 shown, the method includes:

[0062] Step 201: Obtain an optical signal with a first preset wavelength using the tunable laser 1, and measure the first optical power P of the optical signal at this time.

[0063] Among them, the embodiment of the present invention is actually to obtain the phase modulation curve of the LCOS chip 4 at different wavelengths of the tunable laser 1. When the magnitude value of the first preset wavelength set by the optical signal generated by the tunable laser 1 is different, the corresponding phase modulation curve of the LCOS chip 4 is also different. The first preset wavelength of the tunable laser 1 in the embodiment of the present invention can be set according to the actual situation. When the first preset wavelength of the tunable laser 1 is set to a specific value, the tunable laser 1 in the embodiment of the present invention obtains an optical signal with the first preset wavelength, and measures the first optical power P when the tunable laser 1 generates the first preset wavelength. Specifically, it includes: adjusting the wavelength of the tunable laser 1 to the first preset wavelength, directly connecting the tunable laser 1 to the power meter 7, and measuring the first optical power P of the optical signal with the first preset wavelength emitted by the tunable laser 1 through the power meter 7.

[0064] Step 202: Use the driving unit 8 to sequentially load a binary grating with a preset period T on the LCOS chip 4, and use the power meter 7 to record the second optical power P corresponding to each gray level i. i According to the values of the first optical power P and the second optical power P i , obtain the gray level - insertion loss curve of the LCOS chip 4; among them, the gray level value of the first T / 2 period of the binary grating is a first preset fixed value, and the gray level i of the second T / 2 period takes any integer from 0 to 255.

[0065] As Figure 3 shown, it represents a schematic diagram of the binary grating structure loaded on the LCOS chip 4 in the embodiment of the present invention. In the binary grating structure, the driving unit 8 is used to set the gray level value of the first T / 2 period of the binary grating to a first preset fixed value. The gray level value of the first T / 2 period of the binary grating in the embodiment of the present invention is selected from 0 to 255 according to the actual situation, and can take any integer value from 0 to 255. Usually, it is preferably set to 0, 128 or 255; the gray level of the second T / 2 period of the binary grating is an adjustable value. The driving unit 8 is used to adjust the gray level value i of the second T / 2 period of the binary grating, and the power meter 7 is used to measure the second optical power P of the corresponding optical signal when the second T / 2 period is at different gray level values. i Furthermore, through the first optical power P and the second optical power P i , fit the gray level - insertion loss curve of the LCOS chip 4.

[0066] Step 203: Calculate the phase modulation curve of the LCOS chip 4 according to the gray level - insertion loss curve of the LCOS chip 4.

[0067] Among them, after obtaining the gray scale - insertion loss curve of the LCOS chip 4 in the embodiment of the present invention, the phase modulation curve of the LCOS chip 4 is calculated as follows Figure 4 shown, specifically including:

[0068] Step 301: According to the gray scale - insertion loss curve of the LCOS chip 4 and the conversion formula between the gray scale i and the phase difference calculate the phase difference

[0069] corresponding to different gray scales i in the embodiment of the present invention The conversion formula between the gray scale i and the phase difference

[0070]

[0071] is: where the gray scale i takes an integer from 0 to 255, i represents the phase difference corresponding to the gray scale i, and IL represents the insertion loss value corresponding to the gray scale i. It should be noted that after the LCOS chip 4 in the embodiment of the present invention receives the control voltage signal given by the corresponding driving unit 8, the LCOS chip 4 is equivalent to a binary grating. The phase difference Figure 3 in the embodiment of the present invention actually represents the phase difference between two steps of the binary grating (see Figure 3 shown).

[0072] Among them, as Figure 5 shown, represents the gray scale - insertion loss curve in the embodiment of the present invention; according to the gray scale - insertion loss curve and the above - mentioned conversion formula between the gray scale i and the phase difference the phase difference

[0073] corresponding to different gray scales i within the binary grating can be calculated Step 302: Taking the phase difference corresponding to the gray scale i = 0 as a reference, calculate the phase modulation amount corresponding to the gray scale i as the difference between and

[0074] Perform curve fitting on the gray scale i and the corresponding phase modulation amount to obtain the phase modulation curve of the LCOS chip 4 Figure 6 shown, represents the curve graph of the phase difference corresponding to different gray scales i in the embodiment of the present invention. The phase modulation curve of the LCOS chip 4 in the embodiment of the present invention is obtained by fitting the gray scale i and the phase modulation amount. In order to obtain the phase modulation amount at the gray scale i, the embodiment of the present invention takes the phase difference corresponding to the gray scale i = 0 as a reference. The phase modulation amount in the embodiment of the present invention actually refers to the phase difference of the gray scale i Phase difference from gray scale 0 The difference between them is fitted by the gray scale i of the binary grating and the obtained phase modulation amount, and then the phase modulation curve of the LCOS chip 4 is obtained.

[0075] Such as Figure 7 shown, which represents the phase modulation curve of the LCOS chip 4 corresponding to the first preset wavelength of the optical signal emitted by the tunable laser 1 according to the embodiment of the present invention; when it is necessary to obtain the phase modulation curve of the LCOS chip 4 at other wavelengths, change the wavelength of the tunable laser 1, and obtain the phase modulation curve of the LCOS chip 4 after changing the wavelength according to the method of the embodiment of the present invention.

[0076] To elaborate on the complete solution of the embodiment of the present invention, the details of the present invention will be described in detail below. In the embodiment of the present invention, the binary grating with a preset period T is sequentially loaded on the LCOS chip 4 by the driving unit 8, and the power meter 7 is used to record the second optical power P corresponding to each gray scale i i , and the gray scale - insertion loss curve of the LCOS chip 4 is obtained according to the values of the first optical power P and the second optical power P i ; as Figure 8 shown, specifically including:

[0077] Step 401: Set the first preset fixed value of the gray scale value of the first T / 2 period of the LCOS chip 4; traverse 256 gray scales for the gray scale value i of the second T / 2 period of the LCOS chip 4 from 0 to 255, and record the second optical power P at each gray scale through the power meter 7 i .

[0078] Among them, in the embodiment of the present invention, the LCOS chip 4 is adjusted by the driving unit 8 to traverse the gray scale value i of the second T / 2 period from 0 to 255. The specific traversal process is: when i = 0, the corresponding P0 is measured by the power meter 7, when i = 1, the corresponding P1 is measured by the power meter 7,..., when i = 255, the corresponding P 255 is measured by the power meter 7.

[0079] Step 402: Calculate the difference between the first optical power P and the second optical power P at each gray scale i , obtain the insertion loss corresponding to each gray scale, and perform curve fitting on the gray scale and the corresponding insertion loss to obtain the gray scale - insertion loss curve of the LCOS chip 4.

[0080] Such as Figure 5As shown, it represents the gray scale - insertion loss curve of the LCOS chip 4 corresponding to the first preset wavelength of the optical signal emitted by the tunable laser 1 in the embodiment of the present invention. When the second optical power P i (i = 0, 1, 2, …, 255) corresponding to the gray scale i (i = 0, 1, 2, …, 255) is obtained, by calculating the difference between the first optical power P and the second optical power P i at each gray scale, the insertion loss at the gray scale i is obtained, and then the gray scale and the insertion loss are curve - fitted to obtain the gray scale - insertion loss curve of the LCOS chip 4.

[0081] The device for LCOS chip phase calibration in the embodiment of the present invention includes a tunable laser 1, a collimator 2, a polarizer 3, an LCOS chip 4, a focusing lens 5, a diaphragm 6, a power meter 7, and a driving unit 8; and the formed device optical path is simple, with fewer optical elements required, the calibration method is easy to operate, reading the power test result through the power meter 7 is intuitive and accurate, the speed of obtaining the test result is fast, and it can effectively improve the efficiency and accuracy of LCOS chip 4 phase calibration.

[0082] The above are only the 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 principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An apparatus for phase calibration of an LCOS chip, characterized in that, The device is used for calibrating the phase of an LCOS chip (4), and the device includes a tunable laser (1), a focusing lens (5), a power meter (7) and a driving unit (8); The tunable laser (1) is used for generating an optical signal with a preset wavelength; The LCOS chip (4) is coupled in the optical path generated by the tunable laser (1) and is used for converting the received optical signal into a reflected light; The focusing lens (5) and the power meter (7) are sequentially coupled in the optical path of the reflected light converted by the LCOS chip (4); The driving unit (8) is electrically connected to the LCOS chip (4) and is used for loading a binary grating with a preset period on the LCOS chip (4) so as to calibrate the phase of the LCOS chip (4) through the gray-scale value of the binary grating.

2. The apparatus for LCOS chip phase calibration according to claim 1, wherein It further includes a collimator (2), a polarizer (3) and a diaphragm (6); The collimator (2) and the polarizer (3) are sequentially coupled between the tunable laser (1) and the LCOS chip (4); The diaphragm (6) is arranged between the focusing lens (5) and the power meter (7), and the diaphragm (6) is arranged on the rear focal plane of the focusing lens (5).

3. The device for LCOS chip phase calibration according to claim 2, characterized in that, The polarization direction of the polarizer (3) is consistent with the optical axis direction of the liquid crystal molecules inside the LCOS chip (4).

4. The device for LCOS chip phase calibration according to claim 1, characterized in that It further includes a control unit (9), and the control unit (9) is electrically connected to the driving unit (8) so as to control the driving unit (8) to adjust the phase of the LCOS chip (4).

5. The device for phase calibration of the LCOS chip according to claim 4, characterized in that, A display unit is arranged in the control unit (9), and the display unit is electrically connected to the power meter (7) and is used for displaying the optical power value measured by the power meter (7).

6. A method for phase calibration of an LCOS chip, characterized in that, The method is applicable to the device for calibrating the phase of the LCOS chip according to any one of claims 1-5, and the method includes: Obtaining an optical signal with a first preset wavelength by using the tunable laser (1) and measuring the first optical power P of the optical signal at this time; The driving unit (8) is used to sequentially load a binary grating with a preset period T on the LCOS chip (4), and the power meter (7) is used to record the second optical power P corresponding to each gray level i i , and the gray level-loss curve of the LCOS chip (4) is obtained according to the values of the first optical power P and the second optical power P i ; wherein, the gray level value in the first T / 2 period of the binary grating is a first preset fixed value, and the gray level i in the second T / 2 period takes any integer from 0 to 255; Calculating a phase modulation curve of the LCOS chip (4) according to the gray-scale - insertion loss curve of the LCOS chip (4).

7. The method for phase calibration of an LCOS chip according to claim 6, wherein The binary grating with a preset period T is sequentially loaded on the LCOS chip (4) by using the driving unit (8), and the second optical power P corresponding to each gray level i is recorded by using the power meter (7). i , and the gray level - insertion loss curve of the LCOS chip (4) is obtained according to the values of the first optical power P and the second optical power P i ; specifically, it includes: Setting a first preset fixed value for the gray-scale value of the first T / 2 period of the LCOS chip (4); Traverse 256 gray levels for the gray level value i of the second T / 2 period of the LCOS chip (4) from 0 to 255, and record the second optical power P at each gray level through the power meter (7). i ; Calculate the difference between the first optical power P and the second optical power P at each gray level, obtain the insertion loss corresponding to each gray level, and perform curve fitting on the gray level and the corresponding insertion loss to obtain the gray level-insertion loss curve of the LCOS chip (4). i ​ 8. The method for phase calibration of an LCOS chip according to claim 6, wherein The calculating the phase modulation curve of the LCOS chip (4) specifically includes: According to the gray-scale - insertion loss curve of the LCOS chip (4) and the conversion formula between gray scale i and phase difference calculate the phase difference corresponding to different gray scales i Using the phase difference corresponding to the gray level i = 0 as a reference, the phase modulation amount corresponding to the gray level i is calculated as the difference from is obtained, and the gray level i and the corresponding phase modulation amount are curve-fitted to obtain the phase modulation curve of the LCOS chip (4).

9. The method for phase calibration of an LCOS chip according to claim 8, characterized in that, The gray level i and the phase difference The conversion formula is as follows: Among them, the gray level i takes an integer from 0 to 255, represents the phase difference with the gray level i, IL i represents the insertion loss value with the gray level i.

10. The method for phase calibration of the LCOS chip according to claim 6, characterized in that, Obtaining an optical signal with a first preset wavelength by using the tunable laser (1) and measuring the first optical power P when the tunable laser (1) generates the first preset wavelength, specifically including: adjusting the wavelength of the tunable laser (1) to the first preset wavelength and directly connecting the tunable laser (1) to the power meter (7) to measure the first optical power P of the tunable laser (1).

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