CN114665970A

CN114665970A - Optical modulator and transmitting device

Info

Publication number: CN114665970A
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: 2022-06-24
Anticipated expiration: 2040-12-24
Also published as: CN114665970B

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 the plurality of phase shifter segments are optically coupled to the waveguide, the plurality of phase shifter segments for modulating the continuous light carried in the waveguide according to the electrical drive signal to generate the 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 used for forming an equivalent resistor or an equivalent capacitor. By forming the equivalent capacitor, the optical modulator disclosed by the application reduces the length of the isolation region, and further reduces the driving power consumption.

Description

Optical modulator and transmitting device

Technical Field

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

Background

The optical modulator is used for modulating the electric signal into an optical signal. The communication capacity of a single wavelength can be effectively improved by using the modulation of the high-order coding format.

To achieve low cost high order code format modulation, a segmented modulator needs to be used. A 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 the light in the modulated optical path by receiving the 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 segments, which may be understood as 1 and 0, for example. However, the phase shifter segments are electrically driven, and when different phase shifter segments are applied with different driving states, the voltages on the phase shifter segments are different, and electrical crosstalk occurs between the phase shifter segments. The degree of electrical crosstalk is related to the distance between adjacent phase shifter segments. The distance may be understood as the length of the intrinsic semiconductor between adjacent phase shifter segments. In the related art, the electrical crosstalk is reduced by increasing the distance.

However, this approach reduces the length of the phase shifter segments without changing the length of the optical modulator. The shorter the length of the phase shifter section, the higher the voltage required to drive the electrical signal, resulting in increased drive power consumption.

Disclosure of Invention

The present application provides an optical modulator and an emission device, which can reduce the length of a first isolation region by forming an equivalent capacitance. And then under the condition that the length of the optical modulator is not changed, the length of the phase shifter section is increased, and the driving power consumption is reduced.

A first aspect of the present application provides an optical modulator. The optical modulator includes: a waveguide, a plurality of phase shifter segments. Wherein the plurality of phase shifter segments are optically coupled to the waveguide, the plurality of phase shifter segments for modulating the continuous light carried in the waveguide according to the electrical drive signal to generate the 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 replacement or doping. Replacement refers to a process of cutting off the intrinsic semiconductor between the first N-doped region and the second N-doped region 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 the P-doped region. The first isolation region obtained by replacement or doping can be used to form an equivalent capacitance. The first isolation region is used for forming the equivalent capacitor, which means that the first isolation region is an equivalent capacitor; or, due to the existence of the first isolation region, 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.

In the application, the length of the first isolation region can be reduced by forming the equivalent capacitor. And then under the condition that the length of the optical modulator is not changed, the length of the phase shifter section is increased, and the driving power consumption is reduced. And under the condition that the length of the phase shifter section is not changed, the volume of the optical modulator is hopefully reduced, the integration level is improved, and the cost is reduced.

In an optional manner 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 capacitor, or the second doped region and the third P-doped region form an equivalent capacitor. 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 with 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, so that the optical power loss is reduced.

In an alternative form of the first aspect of the present 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 doping area and the second P doping area are both required to be 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 present application, the first isolation region has a width equal to a width of the first phase shifter section.

In an alternative form of the first aspect of the present application, the length of the first isolation region is less than or equal to 1000 nanometers. In the related art, in which doping or replacement is not used, the length of the isolation region is generally greater than 20000 nm to ensure the isolation. Whereas in the present application the length of the first isolation region is as short as possible above the lowest limit. But limited to the process level of processing, the present application contemplates a first isolation region length of 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 driving signal. Specifically, the higher the doping concentration of the first isolation region is, the better the isolation effect is. In the present application, it is defined that the doping concentration of the first isolation region and the doping concentration of the first P-doped region are synchronized. Under the condition that the electric drive signal is not over-frequency, the requirement of isolation can be met, and the cost can be kept low.

In an optional manner 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 through a same mask. 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 first isolation region has a doping concentration greater than the doping concentration of the first P-doped region and the concentration of the second P-doped region. The electrical chip bandwidth compensation (also called electric drive bandwidth compensation) can improve the bandwidth of the optical modulator through the overclocking of the electric drive signal. As can be seen from the above description, the doping concentration of the first isolation region is related to the frequency of the electrical drive signal. In the event of an electrical drive signal overclock, 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 signal light is improved, and the communication quality is guaranteed.

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. In addition, when the doping concentration of the first isolation region is 10 times or more, the cost is increased due to the increase of the doping concentration of the first isolation region. While electrical chip bandwidth compensation can typically only boost 10% to 20% of the bandwidth. Therefore, by limiting the doping concentration of the first isolation region, the cost can be reduced while satisfying the isolation.

In an alternative form of the first aspect of the present application, the optical modulator includes a plurality of isolation regions, the plurality of isolation regions includes a first isolation region, the number of isolation regions is less than the number of phase shifter segments by 1, and the phase shifter segments and the isolation regions are alternately arranged. The cost of the optical modulator is also reduced by replacing or doping the original partial isolation region.

In an alternative form of the first aspect of the present application, the length of each isolation region is equal, the voltage of the driving electrical signal applied to each phase shifter segment is equal, and the lengths of the plurality of phase shifter segments decrease by a factor of two.

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

In an alternative form of the first aspect of the present application, 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.

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

In this application, the length of the first isolation region is reduced by replacing the intrinsic semiconductor of the waveguide. And then under the condition that the length of the optical modulator is not changed, the length of the phase shifter section is increased, and the driving power consumption is reduced. And under the condition that the length of the phase shifter section is not changed, the volume of the optical modulator is hopefully reduced, the integration level is improved, and the cost is reduced.

A third aspect of the present application provides a transmitting apparatus. The transmitting device includes: a laser, a driver, and the optical modulator of the first aspect or any alternative of the first aspect; the laser is used for generating continuous light and providing the continuous light for the optical 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 drive signal to obtain signal light.

Drawings

Fig. 1 is a schematic view of a light system structure of an application scenario of the present application;

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

FIG. 3 is an expanded view of a ring 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 structure of an M-Z modulator in the embodiment of the present application;

fig. 6 is a schematic structural diagram of a transmitting device provided in an embodiment of the present application.

Detailed Description

The application provides an optical modulator and an emitting 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 capacitor or an equivalent resistor. Under the condition that the length of the optical modulator is not changed, the length of the phase shifter section is expected to be increased, and then the driving power consumption is reduced.

To facilitate understanding of the optical modulator in the embodiment of the present application, an optical system in optical communication will be briefly described below.

Fig. 1 is a schematic view of a light 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. The optical transmitter 101 includes an encoder 104, an optical modulator 105, and a light source 102. The light modulator 105 is coupled to the encoder 104 and the light source 102. The encoder 104 is configured to acquire 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 the electrical driving signal, modulate the continuous light according to the electrical driving signal, and output a 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 the demodulation to the decoder 109. The decoder 109 is configured to receive the electrical signal, decode the electrical signal, and output decoded data.

The high-order coding format modulation can effectively improve the communication capacity of the single-wavelength transmission. However, the power consumption of the optical switch is already close to the heat dissipation limit of the switch, and therefore, when the capacity of the communication system is increased, the power consumption of the optical switch must be reduced. The optical switch may be the optical transmitter 101 of 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 section. 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 in the application sets up the isolation region between adjacent phase shifter section, lets the isolation region form equivalent resistance or equivalent capacitance, reduces the length of first isolation region. And then under the condition that the length of the optical modulator is not changed, the length of the phase shifter section is increased, and the driving power consumption is reduced. And under the condition that the length of the phase shifter section is not changed, the volume of the optical modulator is hopefully reduced, the integration level is improved, and the cost is reduced.

The isolation region may be obtained by replacement or doping. When the isolation region is used for forming the equivalent resistor, the isolation region is replaced, and 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. Since the manner of substitution and doping is similar, the manner of formation of the isolation regions will not be distinguished below. In addition, compared with the formation of an equivalent resistor and an equivalent capacitor, the isolation region can theoretically have a shorter length. Therefore, the isolation region will be described below as an example for forming the equivalent capacitance. The optical modulator in the present application may be a micro-ring modulator, or a mach-zehnder modulator. This will be described below by way of example.

Fig. 2 is a schematic structural diagram of a micro-ring modulator in an embodiment of the present application. The light 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, which generates continuous laser light (referred to as continuous light). The continuous light is guided by the input waveguide 202 and enters the ring waveguide 201. The ring waveguide 201 is structured as a ridge waveguide and is obtained by partially etching a semiconductor material.

Ring waveguide 201 is coupled to two phase shifter segments (phase shifter segment 203 and phase shifter segment 205). Between phase shifter segment 203 and phase shifter segment 205, isolation region 204 and isolation region 206 are included. The phase shifter section and the isolation region are each divided into two parts by a dashed line 207, the dashed line 207 generally being the centerline of the ridge waveguide. For convenience of description, fig. 2 is developed in the Z direction of the circumference. Fig. 3 is an expanded schematic view of a ring 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. Phase shifter segment 203 is divided by 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. The isolation region 204 is divided into a P-doped region 2041 and a P-doped region 2042 by dashed lines 207. The P-doped region 2042 is used to electrically connect the P-doped region 2041 with the P-doped region 2052 and the P-doped region 2032.

Phase shifter sectionThe phase shifter segment 203 is also referred to as a Most Significant Bit (MSB) phase shifter segment and the phase shifter segment 205 is also referred to as a Least Significant Bit (LSB) phase shifter segment. The micro-ring modulator implements electro-optical modulation based on a carrier dispersion effect, and generates a Quadrature Amplitude Modulation (QAM) -4 signal by loading a Non-return-to-zero (NRZ) encoded signal on the phase shifter segment 205 and the phase shifter segment 203. Modulators based on carrier dispersion effects typically operate in a reverse biased state to achieve high speed modulators, i.e., the N-doped region is at a higher potential than the P-doped region (e.g., N-doped region 2031 is at 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. Therefore, two PN junctions formed at the interface between the P-doped region 2032 and the isolation region 204, and between the isolation region 204 and the P-doped region 2042 are in a reverse bias state. The PN junction in the reverse bias state has impedance in the order of mega-ohm, so that the leakage current between the N-doped region 2051 and the N-doped region 2031 can be suppressed, that is, the electrical crosstalk between the two phase shifter sections can be suppressed, and the isolation can be improved. The 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 the N-doped region 2031 is 1 and the voltage on the N-doped region 2051 is 0. But due to the presence of electrical crosstalk, the voltage on the N-doped region 2031 will cause a voltage to be present on the N-doped region 2051, assuming that the voltage is X. The degree of isolation can be expressed as

Of course, the isolation may also be expressed by the influence degree of X on the intensity of the continuous light, and the application does not limit the specific calculation method of the isolation.

It should be understood that the modulation scheme used by the modulator is not limited in this application, and the above description is only 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; the isolation region 204 is a first isolation region, or a third P-doped region. The first isolation region is sector shaped and has a plurality of length dimensions. As shown in fig. 2, the length dimensions of the first isolation region include L1, L2, and L3. In this application, the length dimension of the first isolation region is referred to as L2. The width direction in this application is a direction perpendicular to the length direction, for example, the width of the first shifter segment is d 1.

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 capacitor, the position of the equivalent capacitor can be understood as the boundary between the third P-doped region and the first N-doped region. Also, the length of the third P doping region is minimally limited due to the horizontal limitation of the process. Above the minimum limit, the isolation capability of the equivalent capacitance and the length of the third P-doped region are not too much correlated. Therefore, the unbinding of the length and isolation of the first isolation region is achieved. Therefore, the length of the first isolation region in the equivalent capacitance can be smaller than the equivalent resistance. Therefore, the length of the phase shifter section can be increased and the power consumption can be reduced under the condition that the length of the optical modulator is not changed.

The doping concentration and shape of the first isolation region in the embodiment of the present application will be described in addition 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 present application can determine the doping concentration of the first isolation region according to whether the electrical chip bandwidth compensation is performed.

If no electrical chip bandwidth compensation 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 when the optical modulator is processed, the same mask plate is adopted to obtain the first P doping area, the second P doping area and the first isolation area.

If electrical chip bandwidth compensation is expected to be required, the doping concentration of the first isolation region is greater than the doping concentration of the first P-doped region and the concentration of the second P-doped region. And because the improvement of the bandwidth compensation of the electric chip is limited, 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 embodiment, 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 section. The P-doped region 2042 is used to electrically connect the P-doped region 2041 with the P-doped region 2052 and the P-doped region 2032. Accordingly, the width of the P-doped region 2042 may be less than

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

The micro-ring modulator in the present application is described above. It should be understood that the above embodiments are only illustrative. In practice, other embodiments obtained by a person skilled in the art without making any creative effort fall within the protection scope of the present invention.

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

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

The following description will be given taking an example in which the optical modulator is a mach-zehnder (M-Z) modulator. Fig. 4 is a schematic structural diagram of an M-Z modulator in the 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 via an optical splitter (not shown in the figure) with a first waveguide arm 406, a second waveguide arm 407; the output waveguide arm is coupled via an optical combiner at 408 to a first waveguide arm 406, a second waveguide arm 407. A phase shifter segment 403 and a phase shifter segment 405 are coupled to the first waveguide arm 406.

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

The length of the isolation region 404 is L and the width of the isolation region 404 is less than or equal to d 2. In fig. 4, for convenience of illustration, isolation region 404 and phase shifter segment 403, with a space between phase shifter segment 405. In practical applications, there may or may not be a space between isolation region 404 and phase shifter segment 403 and phase shifter segment 405. When a spacer is present, the material of the spacer may be the intrinsic semiconductor of the waveguide.

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

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

In the M-Z modulator, the first phase shifter section, the isolation region, and the second phase shifter section are distributed in a similar order as in the above-described micro-ring modulator. Therefore, the description of the micro-ring modulator in this application may be incorporated into an M-Z modulator. For example, the doping concentration of the isolation region 403 may be referred to the doping concentration of the aforementioned isolation region 204. Conversely, the description of the M-Z modulator in this application may also be incorporated into a micro-ring modulator.

The M-Z modulator in the present application is described above. The M-Z modulator in 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. Regularly distributed holes form a photonic crystal structure.

Also for example, the M-Z modulator is a QAM modulator. In particular, a coupled static phase shifter is provided on the second waveguide arm for producing the 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 may be increased by increasing the number of phase shifter segments. The M-Z modulator will be described by way of example with the number of phase shifter segments being 4.

Fig. 5 is another schematic diagram of an M-Z modulator in 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 a 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, the phase shifter segments and the isolation regions being alternately arranged. In the related art where no replacement or doping is employed, 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 method does not modify the original whole isolation region, but modifies (replaces or dopes) the original partial isolation region, thereby saving the cost. In particular, an unmodified isolation region is at the intersection of the ring 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 length of the plurality of phase shifter segments decreases by a factor of two. Specifically, the length of the

isolation regions

503, 505, 507 are equal. The length of shifter segment 504 is one-half of shifter segment 502, the length of shifter segment 506 is one-half of shifter segment 504, and the length of shifter segment 508 is one-half of 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 optical 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. Laser 610 may be a tunable laser, a DFB laser, a fiber laser, etc., among others. Laser 610 is used to generate continuous light and provide the continuous light to light modulator 630. 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 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 used for modulating the continuous light according to the electric driving signal to obtain a signal light. In particular, the light modulator may be the light modulator in the embodiments corresponding to fig. 2, fig. 4 or fig. 5 described above.

Optionally, the transmitting device 600 further includes a driver 620, and 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-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present 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 solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding 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 are optically coupled to the waveguide, the plurality of phase shifter segments to modulate continuous light carried in the waveguide according to an electrical drive signal to generate signal light;

the plurality of phase shifter segments comprises a first phase shifter segment comprising a first N-doped region and a first P-doped region and a second phase shifter segment comprising 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 capacitor.

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

3. The optical 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. The optical modulator of claim 3, wherein the width of the first isolation region is equal to the width of the first phase shifter segment.

5. The optical 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 optical modulator according to any of claims 1 to 5, wherein the doping concentrations of the first isolation region, the first P-doped region and the second P-doped region are the same.

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

8. The optical modulator of any of claims 1-5, wherein the first isolation region has a doping concentration greater than the doping concentration of the first P-doped region and the doping concentration of the second P-doped region.

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

10. The optical modulator of any of claims 1-8, wherein 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 of the number of phase shifter segments, the phase shifter segments and the isolation regions being alternately arranged.

11. An optical modulator according to claim 10 wherein the isolation regions are each of equal length, the voltage of the driving electrical signal applied to each phase shifter segment is equal, and the lengths of the plurality of phase shifter segments decrease by a factor of two.

12. An optical modulator according to any one of claims 1 to 11, wherein the optical modulator is a micro-ring modulator, the waveguide is an annular waveguide, and the micro-ring modulator further comprises an input waveguide for introducing the continuous light into the annular waveguide.

13. The optical modulator of any of claims 1-11, wherein the optical modulator is a mach-zehnder modulator, wherein the waveguide is a first waveguide arm comprising an input and an output, and wherein the mach-zehnder modulator further comprises a second waveguide arm coupled to the first waveguide arm at the input and the output.

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 optical modulator;

the driver is used for receiving an 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 drive signal to obtain signal light.