CN102088161B - High speed and high power semiconductor light source - Google Patents

Abstract

The invention relates to a high-speed and high-power semiconductor light source. The high-speed and high-power semiconductor light source comprises a p electrode, an n electrode, a main oscillating part and a power amplifying part, wherein the p electrode and the n electrode are arranged oppositely; the main oscillating part is a single-mode high-speed distributed feedback laser diode (DFB-LD) or distribute bragg reflection laser diode (DBR-LD); the power amplifying part is positioned behind the main oscillating part; and an inclination angle is formed between the main axis of the power amplifying part and the main axis of the main oscillating part. The high-speed and high-power semiconductor light source further comprises an isolation groove, wherein the isolation groove is arranged on the p electrode and is positioned between the main oscillating part and the power amplifying part. The high-speed and high-power semiconductor light source can effectively inhibit light feedback and interference among electric signals, has the potential ability of directly modulating and outputting high-speed and high-power light signals, and can obtain directly modulated output light power with several MHz and watt through modulation current with hundreds of milliampere and direct current with amperes.

Description

High speed and high power semiconductor light source

【Technical field】

The invention relates to a semiconductor laser light source, in particular to a high-speed and high-power semiconductor light source.

【Background technique】

The output power of semiconductor lasers used in ordinary communications is generally at the milliwatt level, which cannot meet the needs of high-speed and high-power light sources such as wireless optical communication systems. At present, the method of realizing high-speed and high-power light source is to use semiconductor laser + erbium-doped fiber amplifier, which can obtain a modulation rate of 2.5Gb/s and an output optical power of 100 milliwatts. However, the high-speed and high-power light source produced by this method has the disadvantages of bulky, difficult packaging, low coupling efficiency, large optical power loss, and high cost.

【Content of invention】

The technical problem solved by the present invention is to provide a high-speed and high-power semiconductor light source, which can improve the mutual interference between the DC bias current of the semiconductor optical amplifier and the modulation current of the laser diode, suppress light reflection, and obtain high-quality, high-speed, large-scale power laser beam.

The invention provides a high-speed and high-power semiconductor light source, which includes: a p-electrode and an n-electrode arranged oppositely; a main oscillation part, and the main oscillation part is a single-mode high-speed distributed feedback semiconductor laser (DFB-LD) or a distributed Bragg reflector semiconductor Laser (DBR-LD); the power amplification part is located behind the main oscillation part. Wherein, the main axis of the power amplifying part and the main axis of the main oscillating part have a certain inclination angle, the front end of the power amplifying part is a transition optical waveguide, and the main axis of the main oscillating part and the main axis of the power amplifying part The inclination angle between them is an acute angle, and the smooth connection is realized through the transition optical waveguide. The high-speed and high-power semiconductor light source further includes an isolation groove, which runs through the p-electrode and is located between the main oscillation part and the power amplification part.

According to a preferred embodiment of the present invention, the isolation trench has a depth of 1-6 microns and a width of 5-50 microns.

According to a preferred embodiment of the present invention, the width of the isolation groove is 30 microns.

According to a preferred embodiment of the present invention, a shallow groove penetrating through the n-electrode is provided on the n-electrode opposite to the isolation groove, the depth of the shallow groove is 1-10 microns, and the width is 25-100 microns.

According to a preferred embodiment of the present invention, the length of the transition optical waveguide is 50-300 microns, and the included angle is 5-12 degrees.

According to a preferred embodiment of the present invention, the front end of the power amplifying part is a transitional optical waveguide, and the rear end is a tapered amplifying part, which is smoothly connected between the light output end of the transitional optical waveguide and the tapered amplifying part.

According to a preferred embodiment of the present invention, the front end of the power amplification part is a transitional optical waveguide, and the rear end is a tapered amplification part, and a first Two isolation slots.

According to a preferred embodiment of the present invention, the transitional optical waveguide in the present invention is a curved transitional optical waveguide.

One of the remarkable advantages of the high-speed and high-power semiconductor light source of the present invention is that by adopting structures such as curved transitional optical waveguides and isolation grooves, the interference between optical feedback and electrical signals is effectively suppressed, and it has the ability to directly modulate and output high-speed and high-power optical signals. Potential ability, through the modulation current of 100 milliamps and the direct current of several amperes, the directly modulated output optical power of several megahertz and watts can be obtained.

【Description of drawings】

Fig. 1 is a schematic structural view of the first embodiment of the high-speed and high-power semiconductor light source of the present invention.

FIG. 2 is a top view of the high-speed and high-power semiconductor light source shown in FIG. 1 .

Fig. 3 is a schematic cross-sectional view along the direction A-A of the high-speed and high-power semiconductor light source shown in Fig. 1 .

FIG. 4 is a schematic cross-sectional view of the high-speed and high-power semiconductor light source shown in FIG. 1 along the B-B direction.

Fig. 5 is a schematic structural diagram of the second embodiment of the high-speed and high-power semiconductor light source of the present invention.

FIG. 6 is a top view of the high-speed and high-power semiconductor light source shown in FIG. 5 .

【Detailed ways】

FIG. 1 is a schematic structural diagram of a high-speed and high-power semiconductor light source according to the present invention. Please refer to FIG. 1 , which includes a main oscillation part 101 and a power amplification part 102 . Among them, the main oscillation part 101 is arranged at the starting end of the high-speed high-power semiconductor light source on the optical path, and the power amplification part 102 is arranged behind the main oscillation part 101, and there is an isolation groove 122 in the middle to isolate the two parts.

FIG. 2 is a top view of the high-speed and high-power semiconductor light source shown in FIG. 1 . Please refer to FIG. 2 , the main oscillator part 101 can be a single-mode main oscillator: for example, a distributed Bragg reflection laser diode or a distributed feedback laser diode. Taking the distributed feedback laser diode as an example, the active region width (optical waveguide width) W ₀ of the main oscillating part 101 is about 5-10 microns, and its length L ₁ is adjustable, and L ₁ is between 300-400 microns.

The power amplifying part 102 is arranged at the rear of the main oscillating part 101, and the power amplifying part 102 can be, for example, a tapered optical power amplifier, whose length _L3 is adjustable, and _L3 is about 1000 microns, and its width _W2 is adjustable, _W2 About 600-800 microns. Wherein, the power amplifying part 102 includes a transition optical waveguide 102a and a tapered amplifying part 102b. The transitional optical waveguide 102 a is curved and includes an optical input end 1021 and an optical output end 1022 . The width W _a of the light input end 1021 is the same or similar to the width W ₀ of the active area of the main oscillating part 101 , which is 2-10 microns, and its length L ₂ is adjustable, and L ₂ is between 50-300 microns. The width W _b of the optical output end 1022 of the transitional optical waveguide 102a is the same as or similar to the width of the input end of the tapered amplifying part 102b, and the width _W3 (active region) of the output end of the tapered amplifying part 102b is about 100-400 microns, Preferably, it is 300 microns, and there is an included angle θ between the central axis of the main oscillating part 101 and the central axis of the tapered enlarged part 102b. The included angle θ is an acute angle, and the preferred value range is 5-12 degrees. The curved transition optical waveguide 102a in the present invention can further improve the beam quality of the light beam in this section, increase the output power of single-mode light, and have the effect of good output light mode quality and greater effective power.

FIG. 3 is a schematic cross-sectional view along the direction AA of the high-speed and high-power semiconductor light source shown in FIG. 1 . Fig. 3 shows the multi-layer structure of high-speed and high-power semiconductor light source, which includes n-electrode layer 110, and substrate layer d ₀ , buffer layer d ₁ , first waveguide layer d ₂ , and quantum wells respectively formed on n-electrode 110 in sequence Layer d ₃ , barrier layer d ₄ , second waveguide layer d ₅ , P-type buffer layer d ₆ , etch stop layer d ₇ , first conductive layer d ₈ , second conductive layer d ₉ , ohmic contact layer d ₁₀ and the p-electrode layer 120 .

Wherein, the n-electrode layer 110 and the p-electrode layer 120 can be multi-layer metal layers, which are covered by evaporation or sputtering, and then alloyed at an appropriate temperature to form a low-resistance metal-semiconductor junction. The n-electrode layer metal material adopts Au-Sn system with a thickness of about 150nm-200nm, or adopts In-Sn-Ag system with a thickness of about 200nm-250nm. The metal material of the p-electrode layer can be Zn-Au, Mg-Au, Ti-Pt-Au and the like.

The liner _d0 is formed on the n-electrode layer 110, which can be an n-type InP layer doped with sulfur (S), with a thickness of about 80-120 microns, preferably 90 microns, and a doping quality of about 20×10 ^17-50 ×10 ¹⁷ cm ^-3 .

The p-electrode layer 120 is disposed above the ohmic contact layer d ₁₀ , and the widths of the first confinement layer d ₈ , the second confinement layer d ₉ , the ohmic contact layer d ₁₀ and the p-electrode 120 are the same as the width W ₀ of the active region of the main oscillation part 101 The same, about 2 to 4 microns.

As shown in FIG. 3 , the surface of the high-speed and high-power semiconductor light source may further include a SiN dielectric layer 105 and a polyimide protective layer 107 . Wherein, the SiN dielectric layer 105 covers the upper surface of the etching stop layer _d7 , the polyimide protective layer 107 is arranged above the SiN dielectric layer 105, and the covering height of the SiN dielectric layer 105 and the polyimide protective layer 107 is To be flush with the upper surface of the p-electrode 120 , thereby forming surface protection for the high-speed and high-power semiconductor light source.

FIG. 4 is a schematic cross-sectional view of the high-speed and high-power semiconductor light source shown in FIG. 1 along the axis BB of the optical waveguide. Please refer to FIG. 3 and FIG. 4 together, an isolation groove 122 is also provided between the main oscillation part 101 and the power amplification part 102 of the high-speed and high-power semiconductor light source. The width W ₁ of the isolation trench 122 is 5-50 microns, preferably about 30 microns. The isolation groove 122 penetrates the p-electrode layer 120, the ohmic contact layer _d10 , the second confinement layer _d9 and the first confinement layer _d8 until the upper surface of the etch stop layer _d7 , and its depth _D1 is 1-6 microns, which is relatively The best is about 2 microns.

Furthermore, the high-speed and high-power semiconductor light source can be provided with a shallow groove 112 at the n-electrode 110 relative to the isolation groove 122 . The shallow groove 112 runs through the n-electrode 110 and penetrates _deep into the substrate layer _d0 . The depth _D2 can be 1-10 microns, and the width _W4 is 25-100 microns. The width W ₁ has the following relationship:

W ₄ ≈W ₁ +(10-50) microns.

Please refer to FIG. 4 , the high-speed and high-power semiconductor light source further includes a grating 109 disposed on the second waveguide layer d ₅ , and the grating 109 is carved to the isolation groove 122 and covers the entire main oscillating part 101 .

When the high-speed and high-power semiconductor light source of the present invention is installed, the p-electrode 120 is installed face down, and it is installed in the form of flip-chip, using a special heat sink for electrical isolation; it can also be installed in the form of the n-electrode 110, facing down, Use a conventional heat sink.

When the high-speed and high-power semiconductor light source of the present invention is working, the modulated output signal of the main oscillation part 101 is injected into the power amplification part 102, and through the diffraction traveling wave amplification, the light output with power up to watt level can be obtained. Wherein, the main oscillating part 101 and the power amplifying part 102 are separately biased. For example, the main oscillating part 101 can apply a modulation current to a fixed bias current, apply a fixed bias current to the power amplifying part 102 , and the modulated optical signal outputted by it changes linearly according to the bias current of the power amplifying part 102 . In addition, it is also possible to change the output optical power according to the change of the current of the main oscillation section 101 .

Taking the 1550mn high-speed and high-power semiconductor light source as an example, its main working parameters are as follows:

A. Working wavelength 1550 micron band

B. Working current 2-3A

C. Output optical power about 1-1.5W

D. The working rate is about 2.5Gb/s

Fig. 5 is a schematic structural diagram of the second embodiment of the high-speed and high-power semiconductor light source of the present invention. Fig. 6 is a top view of the second embodiment of the high-speed and high-power semiconductor light source shown in Fig. 5 . The difference between the high-speed high-power semiconductor light source and the high-speed high-power semiconductor light source shown in FIG. 1 is that an isolation groove 123 is further provided between the light output end of the transitional optical waveguide 102a and the tapered amplification part. The width of the isolation groove 123 is 2-5 microns. The isolation groove 123 realizes electrical isolation between the transition optical waveguide 102a and the tapered amplification part 102b in the power amplification part 102, and improves the quality of the single-mode output light.

In summary, the high-speed and high-power semiconductor light source of the present invention effectively suppresses the interference between optical feedback and electrical signals by adopting structures such as curved transitional optical waveguides and isolation grooves, and has the potential ability to directly modulate and output high-speed and high-power optical signals , the directly modulated output optical power of several megahertz and watts can be obtained through the modulation current of 100 milliamperes and the direct current of several amperes. The light source of the invention organically integrates laser technology and traveling wave light amplification technology, and is a high-speed and high-power semiconductor light source that can be widely used in optical fiber communication, wireless optical communication, material processing, laser medical treatment, military and other industries.

In the above embodiments, the present invention is only described as an example, but those skilled in the art can make various modifications to the present invention without departing from the spirit and scope of the present invention after reading this patent application.

Claims (8)

1. A high-speed high-power semiconductor light source, comprising: p-electrodes and n-electrodes arranged oppositely; The main oscillation part, and the main oscillation part is a single-mode high-speed DFB-LD or DBR-LD; a power amplifying part, the power amplifying part is located behind the main oscillating part; It is characterized in that: the main axis of the power amplification part and the main axis of the main oscillation part have a certain inclination angle, the front end of the power amplification part is a transitional optical waveguide, and the main axis of the main oscillation part and the power amplification part The inclination angle between the main axes is an acute angle, and the smooth connection is realized through the transitional optical waveguide. The high-speed and high-power semiconductor light source further includes an isolation groove, which runs through the p-electrode and is located between the main oscillation part and the between power amplification sections. 2. The high-speed and high-power semiconductor light source according to claim 1, characterized in that: the isolation trench has a depth of 1-6 microns and a width of 5-50 microns. 3. The high-speed and high-power semiconductor light source as claimed in claim 1, wherein the width of the isolation groove is 30 microns. 4. The isolation groove of high-speed and high-power semiconductor light source as claimed in claim 1, characterized in that: a shallow groove penetrating through the n-electrode is set on the n-electrode relative to the isolation groove, and the depth of the shallow groove is 1-10 microns, with a width of 25-100 microns. 5. The high-speed and high-power semiconductor light source according to claim 1, characterized in that: the length of the transition optical waveguide is 50-300 microns, and the included angle is 5-12 degrees. 6. The high-speed high-power semiconductor light source as claimed in claim 1, characterized in that: the front end of the power amplification part is a transitional optical waveguide, the rear end is a tapered amplification part, and at the light output end of the transitional optical waveguide Smooth connection with tapered magnification. 7. The high-speed and high-power semiconductor light source as claimed in claim 1, characterized in that: the front end of the power amplification part is a transition optical waveguide, the rear end is a tapered amplification part, and at the light output end of the transition optical waveguide A second isolation groove is further provided between the tapered enlarged part. 8. The high-speed and high-power semiconductor light source according to claim 5, 6 or 7, characterized in that: the transitional optical waveguide is a curved transitional optical waveguide.

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