CN114665970B

CN114665970B - Light modulator and transmitting device

Info

Publication number: CN114665970B
Application number: CN202011554833.4A
Authority: CN
Inventors: 桂成程; 余宇; 付思东
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2020-12-24
Filing date: 2020-12-24
Publication date: 2024-05-17
Anticipated expiration: 2040-12-24
Also published as: CN114665970A

Abstract

The embodiment of the application discloses an optical modulator which is applied to the field of optical communication. The optical modulator includes: a waveguide and a plurality of phase shifter segments. Wherein a plurality of phase shifter segments are optically coupled to the waveguide, the plurality of phase shifter segments for modulating continuous light carried in the waveguide according to the electrical drive signal to generate signal light. The plurality of phase shifter segments includes a first phase shifter segment including a first N-doped region and a first P-doped region and a second phase shifter segment including a second N-doped region and a second P-doped region. A first isolation region is arranged between the first N doped region and the second N doped region, and the first isolation region is used for forming an equivalent resistor or an equivalent capacitor. By forming the equivalent capacitance, the optical modulator disclosed by the application reduces the length of the isolation region, thereby reducing the driving power consumption.

Description

Light modulator and transmitting device

Technical Field

The present application relates to the field of optical communications, and in particular, to an optical modulator and a transmitting device.

Background

The optical modulator is used for modulating the electrical signal into an optical signal. Wherein, the use of higher order code format modulation can effectively improve the communication capacity of single wavelength.

To achieve low cost modulation of higher order coding formats, a segmented modulator needs to be used. The segmented modulator includes a plurality of modulation regions (also referred to as a plurality of phase shifter segments). The plurality of phase shifter segments are optically coupled to the optical path and drive light in the modulated optical path by receiving an electrical drive signal to output signal light. The electrical drive signal effects an adjustment of the intensity or phase of the light by changing the drive state of the phase shifter segment, which can be understood as 1 and 0, for example. The phase shifter segments are electrically driven, however, and electrical crosstalk occurs between the phase shifter segments when the drive states applied by the different phase shifter segments differ. The extent of electrical crosstalk is related to the distance between adjacent phase shifter segments. The distance is understood to be the length of the intrinsic semiconductor between adjacent phase shifter segments. In the related art, the electrical crosstalk is reduced by increasing the distance.

But this approach reduces the length of the phase shifter segment where the length of the optical modulator is unchanged. The shorter the length of the phase shifter segment, the higher the voltage required to drive the electrical signal, resulting in increased drive power consumption.

Disclosure of Invention

The application provides an optical modulator and a transmitting device, which can reduce the length of a first isolation region by forming an equivalent capacitance. Further, the length of the phase shifter section is increased under the condition that the length of the optical modulator is unchanged, and driving power consumption is reduced.

The first aspect of the present application provides an optical modulator. The optical modulator includes: a waveguide, a plurality of phase shifter segments. Wherein a plurality of phase shifter segments are optically coupled to the waveguide, the plurality of phase shifter segments for modulating continuous light carried in the waveguide according to the electrical drive signal to generate signal light. The plurality of phase shifter segments includes a first phase shifter segment including a first N-doped region and a first P-doped region and a second phase shifter segment including a second N-doped region and a second P-doped region. A first isolation region is disposed between the first N-doped region and the second N-doped region. The first isolation region may be obtained by substitution or doping. The replacement refers to cutting the intrinsic semiconductor between the first N-doped region and the second N-doped region by a process, and then replacing the region with another material. The doping is to use the intrinsic semiconductor between the first N doped region and the second N doped region as a P doped region. The first isolation region obtained after replacement or doping can be used to form an equivalent capacitance. The first isolation region being used to form an equivalent capacitance may mean that the first isolation region itself is an equivalent capacitance; or the first N-doped region and the first isolation region or the second N-doped region and the first isolation region form an equivalent capacitance due to the presence of the first isolation region.

In the application, the length of the first isolation region can be reduced by forming the equivalent capacitance. Further, the length of the phase shifter section is increased under the condition that the length of the optical modulator is unchanged, and driving power consumption is reduced. And under the condition that the length of the phase shifter section is unchanged, the volume of the optical modulator is hopeful to be reduced, the integration level is improved, and the cost is reduced.

In an alternative form of the first aspect of the present application, the first isolation region is a third P-doped region. The first N doped region and the third P doped region form an equivalent capacitance, or the second doped region and the third P doped region form an equivalent capacitance. Wherein the third P doped region is obtained by doping. When the replacement is adopted, the contact surface of the first N doped region and the third P doped region can reflect continuous light, so that the optical power loss is caused. Compared to the replacement, the doping does not need to consider the problem of the contact surface between the first N doped region and the third P doped region, thereby reducing the optical power loss.

In an alternative form of the first aspect of the application, the first isolation region extends to a region between the first P-doped region and the second P-doped region. Wherein, the first P doped region and the second P doped region are grounded. When the first isolation region extends to the region between the first P doped region and the second P doped region, the first isolation region does not need to be grounded separately, so that the complexity of a circuit is reduced, and the processing cost is reduced.

In an alternative form of the first aspect of the application, the width of the first isolation region is equal to the width of the first phase shifter segment.

In an alternative form of the first aspect of the application, the length of the first isolation region is less than or equal to 1000 nanometers. In the related art, in which doping or substitution is not used, the length of the isolation region is generally more than 20000 nm in order to secure the isolation. In the present application, however, the shorter the length of the first isolation region is above the minimum limit, the better. But limited to the process level of processing, the present application contemplates that the length of the first isolation region is less than or equal to 1000 nanometers.

In an alternative form of the first aspect of the present application, the doping concentrations of the first isolation region, the first P-doped region and the second P-doped region are the same. Wherein the doping concentration of the first P-doped region is related to the frequency of the electrical drive signal. In general, the higher the frequency of the electrical drive signal, the higher the doping concentration of the first P-doped region. When the first isolation region is a third P doped region, the first N doped region and the third P doped region form a PN junction, and the doping concentration of the first isolation region is also related to the frequency of the electric drive signal. Specifically, the larger the doping concentration of the first isolation region is, the better the isolation effect is. In the application, the doping concentration of the first isolation region and the doping concentration of the first P doping region are defined to be synchronous. Under the condition that the electric drive signal does not exceed frequency, the requirements of isolation can be met, and the cost can be kept low.

In an alternative form of the first aspect of the present application, the first P-doped region, the second P-doped region and the first isolation region are obtained by the same mask plate. The same mask plate is adopted, so that the number of the mask plates can be reduced, and the processing cost is reduced.

In an alternative form of the first aspect of the present application, the doping concentration of the first isolation region is greater than the doping concentration of the first P-doped region and the doping concentration of the second P-doped region. Wherein the electrical chip bandwidth compensation (also called electrical drive bandwidth compensation) can boost the bandwidth of the optical modulator by over-clocking the electrical drive signal. From the above description, it is clear that the doping concentration of the first isolation region is related to the frequency of the electrical drive signal. In case of an over-clocking of the electrical drive signal, the isolation capability of the first isolation region may decrease. Therefore, the doping concentration of the first isolation region is set to be larger than that of the first P doping region, the quality of the signal light is improved, and the communication quality is ensured.

In an alternative form of the first aspect of the present application, the doping concentration of the first isolation region is less than or equal to 10 times the doping concentration of the first P-doped region. Wherein, at least 10 times, the increase of the doping concentration of the first isolation region causes an increase of cost. While electrical chip bandwidth compensation generally can only boost the bandwidth by 10% to 20%. Therefore, by limiting the doping concentration of the first isolation region, the cost can be reduced while the isolation is satisfied.

In an alternative form of the first aspect of the application, the optical modulator comprises a plurality of isolation regions, the plurality of isolation regions comprising the first isolation region, the number of isolation regions being less than 1, the number of phase shifter segments and the isolation regions being alternately arranged. The application replaces or dopes the original partial isolation region, and reduces the cost of the optical modulator.

In an alternative form of the first aspect of the application, the lengths of each isolation region are equal, the voltages of the drive electrical signals applied to each phase shifter segment are equal, and the lengths of the plurality of phase shifter segments are reduced by a proportion of one half.

In an alternative form of the first aspect of the application, the optical modulator is a micro-ring modulator and the waveguide is an annular waveguide, the micro-ring modulator further comprising an input waveguide for introducing continuous light into the annular waveguide.

In an alternative form of the first aspect of the application, the optical modulator is a mach-zehnder modulator, the waveguide is a first waveguide arm, the first waveguide arm comprises an input end and an output end, the mach-zehnder modulator further comprises a second waveguide arm, the second waveguide arm being coupled to the first waveguide arm at the input end and the output end.

A second aspect of the application provides an optical modulator. The optical modulator includes a waveguide and a plurality of phase shifter segments. Wherein a plurality of phase shifter segments are optically coupled to the waveguide, the plurality of phase shifter segments for modulating continuous light carried in the waveguide according to the electrical drive signal to generate signal light. The plurality of phase shifter segments includes a first phase shifter segment including a first N-doped region and a first P-doped region and a second phase shifter segment including a second N-doped region and a second P-doped region. A first isolation region is arranged between the first N doped region and the second N doped region; the first isolation region is used for forming an equivalent resistance, the resistance value of the equivalent resistance is larger than 1000 ohms, and the length of the first isolation region is smaller than 200 nanometers. Wherein the first isolation region may be obtained by replacement. The replacement refers to cutting the intrinsic semiconductor between the first N-doped region and the second N-doped region by a process, and then replacing the region with another material.

In the present application, the length of the first isolation region is reduced by replacing the intrinsic semiconductor of the waveguide. Further, the length of the phase shifter section is increased under the condition that the length of the optical modulator is unchanged, and driving power consumption is reduced. And under the condition that the length of the phase shifter section is unchanged, the volume of the optical modulator is hopeful to be reduced, the integration level is improved, and the cost is reduced.

A third aspect of the application provides a transmitting device. The transmitting device includes: a laser, a driver, and an optical modulator of the first aspect or any of the alternatives of the first aspect; wherein the laser is configured to generate continuous light to provide the continuous light to the light modulator; the driver is used for receiving the electric signal, amplifying the electric signal to obtain an electric driving signal and providing the electric driving signal for the optical modulator; the optical modulator is used for modulating continuous light according to the electric drive signal to obtain signal light.

Drawings

FIG. 1 is a schematic diagram of an optical system of an application scenario of the present application;

FIG. 2 is a schematic diagram of a micro-ring modulator according to an embodiment of the present application;

FIG. 3 is an expanded schematic view of an annular waveguide in an embodiment of the present application;

FIG. 4 is a schematic diagram of an M-Z modulator according to an embodiment of the present application;

FIG. 5 is a schematic diagram of another M-Z modulator according to an embodiment of the present application;

Fig. 6 is a schematic structural diagram of a transmitting device according to an embodiment of the present application.

Detailed Description

The application provides an optical modulator and a transmitting device, which are used in the field of optical communication, and the length of an isolation region is expected to be reduced by forming an equivalent capacitance or an equivalent resistance. In the case where the length of the optical modulator is unchanged, it is expected to increase the length of the phase shifter section, thereby reducing driving power consumption.

In order to facilitate understanding of the optical modulator in the embodiments of the present application, an optical system in optical communication is briefly described below.

Fig. 1 is a schematic diagram of an optical system structure of an application scenario of the present application. As shown in fig. 1, the optical system includes an optical transmitter 101, an optical receiver 107, and an optical fiber 106. Wherein the optical transmitter 101 comprises an encoder 104, an optical modulator 105 and a light source 102. The light modulator 105 and the encoder 104, the light source 102 are coupled. The encoder 104 is configured to acquire the input data 103, encode the data 103 using a driving signal, and transmit the encoded electric driving signal to the optical modulator 105. The light source 102 is used to provide continuous light to the light modulator 105. The optical modulator 105 is configured to receive an electric drive signal, modulate continuous light according to the electric drive signal, and output signal light. The optical signal passes through the optical fiber 106 and reaches the optical receiver 107.

The optical receiver 107 includes an optical demodulator 108 and a decoder 109. The optical demodulator 108 receives the signal light, demodulates the signal light, and outputs an electric signal obtained by demodulation to the decoder 109. The decoder 109 is configured to receive the electrical signal, decode the electrical signal, and output decoded data.

The use of higher order coded format modulation can effectively increase single wavelength transmission capacity. However, the power consumption of the optical switch is already approaching the heat dissipation limit of the switch, so the power consumption of the optical switch must be reduced when the capacity of the communication system is increased. The optical switch may be the optical transmitter 101 in fig. 1 described above. The main power consumption of the optical switch comes from the optical modulator. The power consumption of the optical modulator is inversely proportional to the length of the phase shifter segment. The longer the length of the phase shifter segment, the lower the voltage of the electrical drive signal can be, and thus the lower the power consumption of the optical modulator.

The optical modulator is provided with the isolation regions between the adjacent phase shifter sections, so that the isolation regions form equivalent resistance or equivalent capacitance, and the length of the first isolation region is reduced. Further, the length of the phase shifter section is increased under the condition that the length of the optical modulator is unchanged, and driving power consumption is reduced. And under the condition that the length of the phase shifter section is unchanged, the volume of the optical modulator is hopeful to be reduced, the integration level is improved, and the cost is reduced.

The isolation regions may be obtained by substitution or doping. When the isolation region is used for forming an equivalent resistance and the isolation region is obtained through replacement, the resistance value of the isolation region is larger than 1000 ohms under the condition that the length of the isolation region is smaller than 200 nanometers. The manner of forming the isolation regions will not be distinguished below, since the manner of substitution and doping is similar. And, the isolation region may theoretically have a shorter length when forming the equivalent capacitance than when forming the equivalent resistance. Therefore, the following description will take an example in which the isolation region is used to form an equivalent capacitance. The optical modulator in the present application may be a micro-ring modulator, or a Mach-Zehnder modulator. Hereinafter, this will be described by way of example.

Fig. 2 is a schematic structural diagram of a micro-ring modulator according to an embodiment of the present application. The optical modulator in fig. 1 described above may be a micro-ring modulator. As shown in fig. 2, the micro-ring modulator includes an input waveguide 202 and a ring waveguide 201. The input waveguide 202 receives continuous light provided by a light source, which may be a laser or a laser chip, and the light generated by the laser or the laser chip is continuous laser light (simply referred to as continuous light). The continuous light is guided through the input waveguide 202 and enters the annular waveguide 201. The annular waveguide 201 is structured as a ridge waveguide, and is obtained by partially etching a semiconductor material.

The annular waveguide 201 is coupled to two phase shifter segments (phase shifter segment 203 and phase shifter segment 205). Between the phase shifter segment 203 and the phase shifter segment 205, an isolation region 204 and an isolation region 206 are included. The phase shifter segments and isolation regions are each divided into two parts by a dashed line 207, the dashed line 207 being generally the centerline of the ridge waveguide. For convenience of description, fig. 2 is expanded in the Z direction of the circumference. FIG. 3 is an expanded view of an annular waveguide in an embodiment of the present application. In the developed view of fig. 3, the portion inside the broken line 207 is stretched, and the portion outside the broken line 207 is compressed. The phase shifter segment 203 is divided by a dashed line 207 into an N-doped region 2031 and a P-doped region 2032. The phase shifter segment 205 is divided by a dashed line 207 into an N-doped region 2051 and a P-doped region 2052. Isolation region 204 is divided into P-doped region 2041 and P-doped region 2042 by dashed line 207. The P-doped region 2042 is used to electrically connect the P-doped region 2041 to the P-doped region 2052 and the P-doped region 2032.

The phase shifter segment 203 is also referred to as a most significant bit (most significant bit, MSB) phase shifter segment, and the phase shifter segment 205 is also referred to as a least significant bit (LEAST SIGNIFICANT bit, LSB) phase shifter segment. The micro-ring modulator implements electro-optic modulation based on carrier dispersion effects, and the generation of quadrature amplitude modulation (quadrature amplitude modulation, QAM) -4 signals is achieved by loading Non-return-to-zero (NRZ) encoded signals on the phase shifter segment 205 and the phase shifter segment 203. Modulators based on carrier dispersion effects typically operate in a reverse bias state to achieve high speed modulators, i.e., N-doped regions having a higher potential than P-doped regions (e.g., N-doped region 2031 having a higher potential than P-doped region 2032). The P-doped region 2032, the P-doped region 2042, and the isolation region 204 are commonly connected. The P-doped region 2032 and the isolation region 204, and the two PN junctions formed at the interface of the isolation region 204 and the P-doped region 2042, are thus in a reverse biased state. The reverse-biased PN junction has a megaohm-level impedance, so that leakage current between the N-doped region 2051 and the N-doped region 2031 is suppressed, that is, electrical crosstalk between two phase shifter segments is suppressed, and isolation is improved. Isolation is used to express the magnitude of the effect of one phase shifter segment on the electrical crosstalk of another phase shifter segment. For example, the voltage on N-doped region 2031 is 1 and the voltage on N-doped region 2051 is 0. However, due to the presence of electrical crosstalk, the voltage across N-doped region 2031 may cause a voltage across N-doped region 2051, which is assumed to be X. The isolation can be expressed asOf course, the isolation may also be expressed by the degree of influence of X on the intensity of continuous light, and the present application is not limited to a specific calculation method of the isolation.

It should be understood that the present application is not limited to the modulation scheme used by the modulator, and the above description is merely an example.

The phase shifter segment 203 may be a first phase shifter segment or a second phase shifter segment. When the phase shifter segment 203 is a first phase shifter segment, the N-doped region 2031 is a first N-doped region and the P-doped region 2032 is a first P-doped region; the phase shifter segment 205 is a second phase shifter segment, the N-doped region 2051 is a second N-doped region, and the P-doped region 2052 is a second P-doped region; isolation region 204 is a first isolation region, or a third P-doped region. The first isolation region is fan-shaped and has a plurality of length dimensions. As shown in fig. 2, the length dimension of the first isolation region includes L1, L2, and L3. In the present application, the length dimension of the first isolation region is referred to as L2. The width direction in the present application is a direction perpendicular to the length direction, for example, the width of the first phase shifter segment is d1.

When the first isolation region is used for forming the equivalent resistor, the resistance value of the equivalent resistor depends on the length of the isolation region. When the first N-doped region and the third P-doped region form an equivalent capacitance, the position of the equivalent capacitance can be understood as the junction of the third P-doped region and the first N-doped region. And, the length of the third P-doped region is minimally limited due to the level limitations of the processing process. Above the minimum limit, the isolation capability of the equivalent capacitance and the length of the third P-doped region are not much related. Thus, unbinding of the length and isolation of the first isolation region is achieved. Thus, the length of the first isolation region in the equivalent capacitance may be smaller than the equivalent resistance. Therefore, the length of the phase shifter section can be increased under the condition that the length of the optical modulator is unchanged, and the power consumption is reduced.

The doping concentration and shape of the first isolation region in the embodiments of the present application are described in additional detail below.

In practical applications, the bandwidth of the optical modulator can be increased by electrical chip bandwidth compensation. Therefore, the optical modulator in the embodiment of the application can determine the doping concentration of the first isolation region according to whether the electrical chip bandwidth compensation is performed or not.

If no compensation of the electrical chip bandwidth is expected, the doping concentration of the first isolation region is equal to the doping concentrations of the first P-doped region and the second P-doped region. And the first P doped region, the second P doped region and the first isolation region can be obtained by adopting the same mask plate when the light modulator is processed.

If the need for electrical chip bandwidth compensation is anticipated, the doping concentration of the first isolation region is greater than the doping concentration of the first P-doped region and the doping concentration of the second P-doped region. And because the bandwidth compensation of the electric chip is improved to a limited extent, the doping concentration of the first isolation region can be limited to be less than or equal to 10 times of the doping concentration of the first P doping region.

It should be noted that, in the above implementation, the first isolation region includes the P-doped region 2041 and the P-doped region 2042, and the width of the first isolation region is equal to the width d1 of the first phase shifter segment. The P-doped region 2042 is used to electrically connect the P-doped region 2041 to the P-doped region 2052 and the P-doped region 2032. Thus, the width of the P-doped region 2042 may be less thanAlternatively, the first isolation region may extend to a region between the first P-doped region and the second P-doped region.

In other embodiments, the length of the first isolation region is less than or equal to 1000 nanometers. For example, the length of the first isolation region is 200 nanometers or 100 nanometers.

In other embodiments, isolation region 206 is a fourth P-doped region. The fourth P doped region is used for forming an equivalent capacitance. Specifically, the first N-doped region and the fourth P-doped region form an equivalent capacitance, or the second doped region and the fourth P-doped region form an equivalent capacitance.

The micro-ring modulator of the present application is described above. It should be understood that the above embodiments are only schematically described. In practical applications, other embodiments obtained by those skilled in the art without making any inventive effort are within the scope of the present application.

For example, the micro-ring modulator is a slit micro-ring modulator. On the basis of the above-mentioned micro-ring modulator, the slit micro-ring modulator is provided with a slit along the dashed line 207. The inner side of the slit is an N doped region, and the outer side is a P doped region.

For another example, the micro-ring modulator increases the number of phase shifter segments, and the annular waveguide is coupled to a 4,6, or 8 segment phase shifter segment.

The following description will take an optical modulator as an example of a mach-zehnder (M-Z) modulator. Fig. 4 is a schematic diagram of an M-Z modulator according to an embodiment of the present application. As shown in fig. 4, the M-Z modulator includes a phase shifter section 403, an isolation region 404, a phase shifter section 405, an input waveguide 401, a first waveguide arm 406, a second waveguide arm 407, and an output waveguide 409. The input waveguide arm is coupled at 402 to a first waveguide arm 406, a second waveguide arm 407 via a splitter (not shown); the output waveguide arm is coupled via an optical combiner at 408 with a first waveguide arm 406, a second waveguide arm 407. Phase shifter segment 403, phase shifter segment 405 is coupled to first waveguide arm 406.

The M-Z modulator is used to introduce continuous light from a light source into an input waveguide 401, and the input waveguide 401 is used to introduce continuous light into a first waveguide arm 406 and a second waveguide arm 407 through a beam splitter. The phase shifter section 403 and the phase shifter section 405 are used to modulate continuous light according to an electric drive signal, outputting a first light beam. The P doped region in the phase shifter section is connected with the signal end of the electric drive signal, and the N doped region in the phase shifter section is grounded. The optical combiner combines the first light beam with the second light beam output by the second waveguide arm at 408 to obtain signal light. The output waveguide 409 is used to output the signal light to a target, such as an optical fiber.

The length of isolation region 404 is L and the width of isolation region 404 is less than or equal to d2. In fig. 4, for ease of illustration, there is a separation between isolation region 404 and phase shifter segment 403, phase shifter segment 405. In practical applications, there may or may not be a space between the isolation region 404 and the phase shifter segment 403, and the phase shifter segment 405. When a space is present, the material of the space may be the intrinsic semiconductor of the waveguide.

Isolation region 404 belongs to the P-doped region. The isolation region 404 forms one PN junction with the N-doped region in the phase shifter segment 403 and another PN junction with the N-doped region in the phase shifter segment 405. In operation of the M-Z modulator, the PN junction between isolation region 404 and phase shifter segment 403 or phase shifter segment 405 is in a reverse biased state by control of the external bias. The PN junction in the reverse bias state has extremely high impedance, so that the electric crosstalk caused by leakage current between adjacent phase shifter sections can be effectively restrained, and the isolation degree is improved.

The phase shifter section 403 may be a first phase shifter section and may be a second phase shifter section. When the phase shifter segment 403 is a first phase shifter segment, the N-doped region of the phase shifter segment 403 is a first N-doped region, and the P-doped region of the phase shifter segment 403 is a first P-doped region; the phase shifter segment 405 is a second phase shifter segment, the N-doped region of the phase shifter segment 405 is a second N-doped region, and the P-doped region of the phase shifter segment 405 is a second P-doped region; isolation region 404 is a first isolation region, or a third P-doped region.

In the M-Z modulator, the order of distribution of the first phase shifter section, the isolation region, and the second phase shifter section is similar to that in the micro-ring modulator described above. Thus, the relevant description of the micro-ring modulator in the present application may be cited in the M-Z modulator. For example, the doping concentration of isolation region 404 may be referenced to the doping concentration of isolation region 204 described above. Conversely, the description of the M-Z modulator of the present application may be incorporated into a micro-ring modulator.

The M-Z modulator of the present application is described above. The M-Z modulator of the present application is not limited to the M-Z modulator shown in fig. 4.

For example, the M-Z modulator is a photonic crystal modulator. Specifically, a slit is provided in the center of the first waveguide arm. Regularly distributed holes are arranged on two sides of the slit. The regularly distributed holes form a photonic crystal structure.

For another example, the M-Z modulator is a QAM modulator. Specifically, a coupled static phase shifter is provided on the second waveguide arm for producing a desired fixed phase shift.

Embodiments of a single isolation region (or two phase shifter segments) are described in detail above. In practice, the number of bits of the optical modulator can be increased by increasing the number of phase shifter segments. An example of an M-Z modulator will be described below with a number of phase shifter segments of 4.

Fig. 5 is a schematic diagram of another structure of an M-Z modulator according to an embodiment of the present application. As shown in fig. 5, the M-Z modulator 500 includes an input waveguide 501, a first waveguide arm 509, a second waveguide arm 510, and an output waveguide 511. The first waveguide arm 509 is coupled to the phase shifter segment. The phase shifter segments include phase shifter segments 502, 504,506 and 508. Isolation regions 503, 505, 507 are provided between the phase shifter segments. Wherein the number of isolation regions is 1 less than the number of phase shifter segments, and the phase shifter segments and the isolation regions are alternately arranged. In the related art without substitution or doping, when the optical modulator is a micro-ring modulator, the number of isolation regions and the number of phase shifter segments are equal. As shown in fig. 2, the number of phase shifter segments and isolation regions is 2. The application does not modify the original whole isolation region, but modifies (replaces or dopes) the original part of the isolation region, thereby saving the cost. In particular, the isolation region that is not modified is at the intersection of the annular waveguide and the input waveguide, such as isolation region 206 in FIG. 2.

In other embodiments, the length of each isolation region is equal. The voltages of the driving electrical signals applied to each phase shifter segment are equal. The lengths of the plurality of phase shifter segments decrease in proportion to one half. Specifically, the isolation regions 503, 505, 507 are of equal length. The length of phase shifter segment 504 is one half of phase shifter segment 502, the length of phase shifter segment 506 is one half of phase shifter segment 504, and the length of phase shifter segment 508 is one half of phase shifter segment 506.

The first phase shifter segment and the second phase shifter segment may be any two adjacent phase shifter segments in this embodiment, such as phase shifter segment 504 and phase shifter segment 506 (the first isolation region is isolation region 505). Therefore, the description in this embodiment may refer to the description in the corresponding embodiment of fig. 2 or fig. 4 described above.

The light modulator in the present application is described above, and the transmitting device in the present application is described below. Fig. 6 is a schematic structural diagram of a transmitting device according to an embodiment of the present application. As shown in fig. 6, the transmitting device 600 includes a laser 610, an encoder 640, and an optical modulator 630. The laser 610 may be a tunable laser, a DFB laser, a fiber laser, or the like. The laser 610 is configured to generate continuous light to provide the continuous light to the light modulator 630. The encoder 640 is used to acquire data to be transmitted, encode the data using a drive signal, and transmit the encoded electrical drive signal to the optical modulator 630. The optical modulator 630 may be a level pulse amplitude modulator, a quadrature amplitude modulator, or the like. The optical modulator 630 is configured to modulate continuous light according to an electric drive signal to obtain signal light. In particular, the light modulator may be the light modulator in the embodiments corresponding to fig. 2, fig. 4 or fig. 5.

Optionally, the transmitting device 600 further includes a driver 620, where the driver 620 may be a radio frequency amplifier, a driver chip, or the like. The driver 620 is configured to receive the encoded electrical signal sent by the encoder 640, amplify the electrical signal to obtain an electrical driving signal, and provide the electrical driving signal to the optical modulator 630;

The above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An optical modulator comprising a waveguide and a plurality of phase shifter segments, wherein:

The plurality of phase shifter segments being optically coupled to the waveguide, the plurality of phase shifter segments for modulating continuous light carried in the waveguide according to an electrical drive signal to generate signal light;

The plurality of phase shifter segments includes a first phase shifter segment including a first N-doped region and a first P-doped region and a second phase shifter segment including a second N-doped region and a second P-doped region;

A first isolation region is arranged between the first N doped region and the second N doped region, the first isolation region is a third P doped region, the third P doped region and the first N doped region form a first PN junction, the third P doped region and the second N doped region form a second PN junction, and the first PN junction and the second PN junction are in a reverse bias state under the control of external bias voltage;

the first isolation region is used for forming an equivalent capacitance.

2. The light modulator of claim 1, wherein the first N-doped region and the third P-doped region form the equivalent capacitance or the second N-doped region and the third P-doped region form the equivalent capacitance.

3. The light modulator of claim 2, wherein the first isolation region extends to a region between the first P-doped region and the second P-doped region.

4. A light modulator as claimed in claim 3 wherein the width of the first isolation region is equal to the width of the first phase shifter segment.

5. The light modulator of any of claims 1-4, wherein the length of the first isolation region is less than or equal to 1000 nanometers.

6. The light modulator of any of claims 1-4, wherein the first isolation region, the first P-doped region, and the second P-doped region have a same doping concentration.

7. The light modulator of claim 6, wherein the first P-doped region, the second P-doped region, and the first isolation region are obtained by a same mask.

8. The light modulator of any of claims 1-4, wherein a doping concentration of the first isolation region is greater than a doping concentration of the first P-doped region and a doping concentration of the second P-doped region.

9. The light modulator of claim 8, wherein a doping concentration of the first isolation region is less than or equal to 10 times a doping concentration of the first P-doped region.

10. The light modulator of any one of claims 1-4, wherein the light modulator comprises a plurality of isolation regions including the first isolation region, the number of isolation regions being 1 less than the number of phase shifter segments, the phase shifter segments and the isolation regions alternating.

11. The optical modulator of claim 10 wherein the length of each isolation region is equal and the voltages of the drive electrical signals applied to each phase shifter segment are equal, the lengths of the plurality of phase shifter segments decreasing in a proportion of one half.

12. The optical modulator of any one of claims 1 to 4, wherein the optical modulator is a micro-ring modulator, the waveguide is a ring waveguide, and the micro-ring modulator further comprises an input waveguide for introducing the continuous light into the ring waveguide.

13. The optical modulator of any of claims 1-4, wherein the optical modulator is a mach-zehnder modulator, the waveguide is a first waveguide arm, the first waveguide arm includes an input end and an output end, and the mach-zehnder modulator further includes a second waveguide arm coupled to the first waveguide arm at the input end and the output end.

14. A transmitting device, comprising: a laser, a driver, and the optical modulator of any one of claims 1 to 13, wherein:

the laser is used for generating continuous light and providing the continuous light to the light modulator;

The driver is used for receiving the electric signal, amplifying the electric signal to obtain an electric driving signal and providing the electric driving signal for the optical modulator;

The optical modulator is used for modulating the continuous light according to the electric driving signal to obtain signal light.