JP2006278662A - Optical source for optical communication - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical source which is highly reliable, even if the operating band is raised in a surface light-emitting laser optical source for optical communication. <P>SOLUTION: In the optical source for optical communication for transmitting one signal of a band of at least 5 Gbps, its light projection is constituted of a plurality of vertical resonance type surface light-emitting lasers, disposed within a range of a diameter of at least 100 μm. It has a means for monitoring optical output as the control mechanism of the optical source, a means for determining deterioration of a laser, and a means for switching a drive laser. It drives the surface light emitting laser by switching it one by one. A high-reliability optical source can be obtained by redundancy. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light source for optical communication, and more particularly to a surface-emitting laser light source used for so-called metro access system optical communication and optical interconnection.

  A vertical cavity surface emitting laser (VCSEL) has a smaller active layer volume than an end surface laser, and can oscillate at a low threshold current, and has low power consumption characteristics. ing. In addition, it has many advantages in terms of manufacturing such as low manufacturing cost, high manufacturing yield, and easy secondary array, and has recently been actively used as a light source for metro access systems and optical interconnections. Developments are underway (for the structure and features of surface-emitting lasers, see, for example, “Fundamentals and Applications of Surface-Emitting Lasers, Kyoritsu Shuppan, Iga and Koyama, Chapters 1 and 2”).

  FIG. 1 shows a configuration diagram of a typical surface emitting laser.

  The surface emitting laser includes a lower electrode 1111, a substrate 1011, a lower reflecting mirror structure 1021, a lower cladding layer 1031, a light emitting layer 1041, an upper cladding layer 1051, an AlAs layer 1061, an oxide layer 1062, an upper reflecting mirror structure 1071, and an upper electrode 1101. Are sequentially stacked.

  In this structure, the current confinement structure is formed by partially oxidizing the AlAs layer 1061. Since this oxidized region becomes an insulator, a current can be intensively supplied to the active layer region having a width substantially the same as that of the non-oxidized region in the AlAs layer 1061.

  In the structure of FIG. 1, the active layer volume is defined by the width of the current confinement region, and the transverse mode is controlled. At this time, in order to increase the driving (modulation) band of the laser, it is necessary to reduce the capacitance of the element (that is, relax the so-called CR limiting rate), and to narrow the opening width in the current confinement region. is there. Generally, in order to obtain a modulation band of 5 Gbps, it is necessary to narrow the aperture width to about 15 μm or less.

  The surface emitting laser having the oxidized constriction structure has been applied to many commercial devices because of its simplicity of manufacture. The current commercial devices are mainly 1-2Gbps (bit per second) for Ethernet (registered trademark) and 4Gbps for fiber channel, but due to demand for broadband or ultra-high speed computing, 10Gbps There is a great expectation for a surface emitting laser having a modulation band exceeding.

  As described above, in order to expand the modulation band of the surface emitting laser, it is necessary to narrow the opening diameter in the oxidized constriction region.

  However, it is known that the reliability of the surface emitting laser is greatly deteriorated when the diameter of the oxidized constriction aperture is reduced (more specifically, for example, BM Hawkins, et al., “Reliability of Various Size Oxide Aperture VCSELs ”, Proceedings of 52nd Electronic Components and Technology Conference, 2002, pp.540-550 etc.). This is because crystal defects generated by strain stress at the oxide layer and the semiconductor interface propagate to the active layer and generate a non-light emitting region (for example, DT Mathes, et al., “Nanoscale Materials Characterization of Degradation in VCSELs ”, Proceedings of SPIE, vol. 4994, pp. 67-82, etc.).

  In addition, in an element using an AlGaAs / GaAs active layer having a wavelength of 0.85 μm, which is most commercialized as a surface emitting laser, the rate of growth of crystal defects (dislocations) is particularly high due to the characteristics of the material system. It is known to be fast, and when the oxidized constriction diameter is narrowed in order to expand the modulation band of the element higher than the above 5 Gbps, there arises a problem that the reliability corresponding to the specification for communication cannot be maintained.

  In this regard, as described above, the reliability of a surface emitting laser is largely governed by the growth of crystal defects due to its oxidized constriction structure, and the improvement in reliability of a single device is because the structure is optimized. There is a limit.

Therefore, there is a method of improving the reliability as a light source by several orders of magnitude by adding redundancy using a plurality of lasers when the improvement in the reliability of a single surface emitting laser is limited. An example in which redundancy is added to a normal end face laser is disclosed in, for example, Patent Document 1 below.
JP 2000-196184 A

  FIG. 2 is a configuration example of the laser diode module disclosed in Patent Document 1. The laser diode module 2201 includes a pair of laser diodes (LD) 2211 and 2212 and photodiodes (PD) 2213 and 2214. One LD light output is constantly monitored by the PD, and deterioration of one LD is controlled. 2215, the switching circuit 2216, and the current addition circuit 2217 are used for detection, and when the deterioration is detected, switching to the other LD is performed. At this time, the output of each LD can be coupled to the core 2101 of the optical fiber 2100 using an optical component 2218 such as a prism.

  However, the module configuration shown in FIG. 2 is a form in which each single component is mounted in a can package, and there are problems in the complexity of mounting and the number of components. These increase costs and are not suitable for metro access light sources that require low costs. In addition, with regard to reliability, there is an effect of adding one degree of redundancy, but when both the LDs 2211 and 2212 are deteriorated, the service life is reached. In addition, if an overcurrent flows when the LD is degraded, the control circuit 2215, the switching circuit 2216, the current addition circuit 2217, and the like may be damaged, and the entire module may be degraded.

  Therefore, the present invention has been made in view of the above-described problems, and an object of the present invention is to provide a highly reliable and low-cost light source in broadband optical communication with a bandwidth of 5 Gbps or more.

  In order to solve the above problems, the invention described in claim 1 is an optical communication light source that emits laser light used for optical communication of at least a bandwidth of 5 Gbps or more, and is integrated within a range of at least 100 μm in diameter. A plurality of vertical cavity surface emitting lasers that are arranged and each emit the laser beam, a monitor unit that monitors the output of the laser beam emitted from any one of the surface emitting lasers, and the monitor unit Determining means for determining the state of deterioration in each surface emitting laser based on a monitoring result; and switching drive means for sequentially switching and driving each of the surface emitting lasers one by one based on the determined deterioration state; Is provided.

  In order to solve the above problems, the invention described in claim 2 is an optical communication light source that emits laser light used for optical communication of at least a bandwidth of 5 Gbps or more, and is integrated within a range of at least 100 μm in diameter. A plurality of vertical cavity surface emitting lasers that are arranged and each emit the laser beam, a monitor unit that monitors the output of the laser beam emitted from any one of the surface emitting lasers, and the monitor unit Determining means for determining a deterioration state of each surface emitting laser based on a monitor result; and switching drive means for simultaneously driving at least two of the surface emitting lasers based on the determined deterioration state. Thus, while suppressing the output value of each driven surface emitting laser to be equal to or less than a preset value, the sum of the output values is optical communication in the band. While retaining become greater than or equal to allow for driving each said surface emitting laser includes a switching driving means.

  In order to solve the above problems, the invention according to claim 3 is the optical communication light source according to claim 1 or 2, wherein the monitor means can monitor the output values of all the surface emitting lasers. It has a light receiving area and is arranged on the side opposite to the light emitting side of each surface emitting laser.

  In order to solve the above-mentioned problem, the invention according to claim 4 is the light source for optical communication according to any one of claims 1 to 3, wherein the drive electrodes of the plurality of surface emitting lasers are independent of each other. Fuse means are respectively formed on energization paths corresponding to the drive electrodes.

  In order to solve the above-mentioned problem, according to a fifth aspect of the present invention, in the light source for optical communication according to the fourth aspect, the fuse means is a reversible switch by voltage application utilizing a metal redox action. Is formed.

  In order to solve the above-described problem, the invention according to claim 6 is the optical communication light source according to any one of claims 1 to 5, wherein each of the surface emitting lasers is a first conductivity type substrate. A first conductivity type DBR (Distributed Bragg Reflector) layer, an active layer, and a second conductivity type DBR layer are sequentially stacked on the first conductivity type DBR layer or the second conductivity type. Between the active layer and the current confinement portion from the end face of the trench formed between the adjacent surface emitting lasers. The trench is formed of an oxide layer that is oxidized in a direction perpendicular to the emission direction, and the trench further includes an element isolation structure that blocks crystal defect growth between the surface emitting lasers.

  In order to solve the above-described problem, according to a seventh aspect of the present invention, in the optical communication light source according to the sixth aspect, the oxide layer is formed by etching from an end surface of the trench and a surface of the surface emitting laser. It is formed of the oxide layer oxidized in the perpendicular direction from the end face of the formed hole.

  And by each structure mentioned above, in this invention, since it provides in the state which integrated several surface emitting laser, and also switches and drives according to those deterioration states, in the broadband optical communication of the band 5Gbps or more It is possible to provide a light source with extremely high reliability and low cost.

  As described above, according to the present invention, a plurality of surface-emitting lasers are switched and driven one by one, or two or more of the plurality of surface-emitting lasers are simultaneously driven to suppress each laser output. In the light source for optical communication consisting of a plurality of surface emitting lasers having characteristics of at least a band of 5 Gbps or more by adopting the form, and including the element form and control form enabling it, extremely high reliability Can be obtained.

  Furthermore, the fact that it has a structure for improving the reliability of each surface emitting laser itself at the time of high-density integration also has the meaning of increasing its effect.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(I) First Embodiment A first embodiment of a light source for optical communication according to the present invention will be described with reference to FIG.

  First, the configuration of a single surface emitting laser will be described with reference to FIG.

  The surface emitting laser 10 includes a first DBR (Distributed Bragg Reflector) layer 2, a first cladding layer 3, an active layer 4, a second cladding layer 5, an oxidation current confinement layer forming layer 6, and a second DBR layer 7 on a substrate 1. Are sequentially stacked. In addition, the upper electrode 8 is in electrical contact with the second DBR layer 7 and the lower electrode is in contact with the first DBR layer 2.

  Next, regarding the optical communication light source of the present invention, the form of integration of the surface emitting laser 10 will be described with reference to the top view of FIG. In FIG. 3B, the four surface emitting lasers 10 are integrated in a range of 50 μm in diameter, but the light emitting part of each surface emitting laser 10 is arranged in the range of 100 μm in diameter. In this case, the number of surface emitting lasers 10 integrated is not limited.

  As a specific configuration, four surface emitting lasers 10 are arranged in the center, and an upper electrode pad 11 drawn from the upper electrode 8 and a lower electrode pad 12 drawn from the lower electrode 9 are divided into four parts. The surface emitting laser 10 is disposed so as to surround it.

  Further, the laser module 18 as a light source for optical communication according to the present invention is completed by flip-chip mounting the substrate 13 on which the surface emitting laser 10 is integrated and arranged on the flexible substrate 15. A side view of the embodiment is shown in FIG. At this time, the integrated substrate 13 is disposed in electrical contact with the wiring on the flexible substrate 15 via the bump electrodes 14 so that the laser light from each surface emitting laser 10 is on the flexible substrate 15 side. .

  Here, the laser light output from the integrated substrate 13 passes through the transparent flexible substrate 15 and is directly coupled to the core 17 of the fiber 16. Thereby, a light source can be formed without additional optical components such as a lens, and a low-cost light source can be realized. A control circuit 19, a switching circuit 20, a current addition circuit 21, and the like are formed on the flexible substrate 15 and are electrically coupled to each surface emitting laser 10.

  Next, a manufacturing method for two surface emitting lasers 10 shown in FIG. 3A will be described with reference to FIGS. The following description is an example of a short wavelength laser device, and a material having an oscillation wavelength of about 0.85 μm is selected.

First, as shown in FIG. 5A, a basic unit of a pair of an n-type Al _0.2 Ga _0.8 As layer and an n-type Al _0.9 Ga _0.1 As layer is formed on an n-type GaAs substrate 1. A first DBR layer 2 in which a plurality of DBRs (n-type semiconductor mirror layers) are stacked, a first cladding layer 3 of n-type Al _0.3 Ga _0.7 As, and a non-doped Al _0.2 Ga _0.8 As quantum well And a GaAs barrier layer, a p-type Al _0.3 Ga _0.7 As second cladding layer 5, and a p-type Al _x Ga _1-x As (where 0 <x <1) oxidation current confinement portion. The formation layer 6 is a second layer in which a plurality of DBRs (p-type semiconductor mirror layers) having a basic unit of a pair of a p-type Al _0.2 Ga _0.8 As layer and a p-type Al _0.9 Ga _0.1 As layer are stacked. The DBR layer 7 is sequentially deposited by metal organic chemical vapor deposition (MOCVD) (step 1). Of course, other crystal growth methods such as molecular beam epitaxy (MBE) may be used.

In each of the DBR layers 2 and 7, the film thicknesses of Al _0.2 Ga _0.8 As having a high refractive index and Al _0.9 Ga _0.1 As having a low refractive index are different from each other in the medium. The optical path length is set to be approximately 1/4 of the oscillation wavelength. Alternatively, the total thickness of the Al _0.2 Ga _0.8 As thickness and the Al _0.9 Ga _0.1 As thickness (thickness in units of DBR layers) is set so that the optical path length is ½ of the oscillation wavelength. You may set so that.

  Next, as shown in FIG. 5B, a photoresist 22-1 is applied onto the second DBR layer 7 to form a circular resist mask (step 2). Next, etching is performed by dry etching until the surface of the first cladding layer 3 is exposed, thereby forming a columnar structure having a diameter of about 30 μm (step 3).

  Then, heating is performed at a temperature of about 400 ° C. for about 10 minutes in a furnace in a steam atmosphere (step 4). As a result, as shown in FIG. 6A, the current confinement portion forming layer 6 is selectively oxidized in an annular shape. By this oxidation, a non-oxidized region 6-1 having a diameter of about 10 μm is formed in the central portion of the current confinement portion forming layer 6.

  A configuration formed of the oxidized region and the non-oxidized region 6-1 formed in the current confinement portion forming layer 6 is referred to as a current confinement portion. The current confinement part is provided in order to concentrate the current in the active layer region having substantially the same width as the non-oxidized region 6-1.

  Further, as shown in FIG. 6B, a photoresist 22-2 at a predetermined position is formed on the substrate surface to form the upper electrode 7 (step 5). Then, as shown in FIG. 6C, titanium (Ti) and gold (Au) are vapor-deposited as an electrode 8 on the entire surface of the substrate on which the columnar structure is formed (step 6). Thereafter, the photoresist 22-2 is removed and lifted off, whereby the upper electrode 8 is formed as shown in FIG. 7A (step 7).

  Finally, through the same process, as shown in FIG. 7B, an AuGe (germanium) alloy is deposited on the first DBR layer 2 and heated to be alloyed to form the lower electrode 9 (process). 8).

  FIGS. 5 to 7 show how two surface emitting lasers 10 are formed on the same substrate. As described above, the number of surface emitting lasers 10 to be integrated is such that the light emitting portion has a diameter of 100 μm. There is no limitation on the number of stacked elements as long as they are arranged within the range. In addition, regardless of the number of surface emitting lasers 10 to be integrated, a large number of surface emitting lasers 10 can be formed simultaneously with the configuration shown in FIGS.

  The laser module 18 of FIG. 3 obtained by the above manufacturing method is driven by sequentially switching a plurality of integrated surface emitting lasers 10 one by one. At this time, the reliability of the surface emitting laser 10 alone has a certain lifetime due to proliferation of crystal defects and the like as described above, but the output light from each surface emitting laser 10 is constantly monitored and the output reduction is preset. The control circuit 19 determines when the threshold value falls below the threshold value, and the switching circuit 20 operates to drive another surface emitting laser 10. With this configuration, for example, when n surface emitting lasers are integrated, it is possible to obtain a reliability n times the life of the surface emitting laser 10 alone.

(II) Second Embodiment A second embodiment of the light source for optical communication according to the present invention will be described.

  The structure and manufacturing method of the light source are the same as those described with reference to FIGS. The difference from the first embodiment is the driving method of each surface emitting laser 10. In the second embodiment, at least two integrated surface emitting lasers 10 are driven simultaneously. The total output light from the plurality of surface emitting lasers 10 is constantly monitored by one monitor, and a feedback signal is output from the control circuit 19 so that the total sum of the output lights is kept constant, and is supplied to each surface emitting laser 10. Control the drive current.

  In the second embodiment, the sum of the output lights of the plurality of surface emitting lasers 10 only needs to have a predetermined light intensity. In other words, the output of each surface emitting laser 10 is the case of the surface emitting laser 10 alone. Thus, the number of integration can be reduced. Therefore, the lifetime of the surface emitting laser 10 that constitutes it can be greatly improved.

  Further, even if one of the constituent surface emitting lasers 10 becomes unable to emit light due to accidental deterioration, it can be supplemented by slightly increasing the outputs of the remaining plurality of surface emitting lasers 10, and the reliability of the entire laser module can be compensated. The sex is extremely high.

  Furthermore, when a plurality of surface emitting lasers 10 that are driven simultaneously are set as group A, other groups of surface emitting lasers 10 such as group B and group C can be formed depending on the number that can be integrated. If considered as redundancy, the effect described in the first embodiment can be similarly applied between the groups.

(III) Third Embodiment A third embodiment of the laser module according to the present invention will be described with reference to FIG. FIG. 8 is a cross-sectional view of the laser module 18. A photodiode (PD) 301 having a corresponding light receiving area diameter is provided for each surface emitting laser so that the light output of all of the plurality of surface emitting lasers 10 arranged (detecting leakage light output on the opposite side of the emission side) can be monitored. 10 on the back side.

  In the first embodiment, the monitor photodiode 301 detects the output of one surface-emitting laser 10 to be driven, and in the second embodiment, the sum of the outputs of the plurality of surface-emitting lasers 10 to be driven. In the former case, the surface emitting laser 10 to be driven is switched by the switching circuit 20, and in the latter case, the control circuit 19 is set so that the light output is constant. The driving current of each surface emitting laser 10 is controlled.

(IV) Fourth Embodiment A fourth embodiment of the laser module according to the present invention will be described with reference to FIG. FIG. 9 is a top view of a four-element integrated configuration in which the fuse portion 302 is provided in the current path to each surface emitting laser 10 in the laser module. A part of the wiring to the upper electrode 8 of each surface emitting laser 10 is formed with a fuse portion 302 made of a material having a fuse function, and is disconnected when a value exceeding a certain current flows.

  As described above, the deterioration of the surface emitting laser 10 is caused by the fact that the crystal defects grow in the active layer and the light emission efficiency is lowered. As a result, there are cases where the element is disconnected or short-circuited as a form of failure. As described in the first embodiment, a decrease in the light emission efficiency of the surface emitting laser 10 to be driven is always detected by the monitor, and the surface emitting laser 10 to be driven is switched at a certain threshold. However, when the short-circuit mode is instantaneously caused by sudden deterioration, or when a plurality of surface-emitting lasers 10 are driven simultaneously as in the second embodiment, destruction of other elements due to overcurrent conduction, or There is a possibility that all element characteristics may be affected by a decrease in current value.

  According to the configuration of FIG. 9, even when one surface emitting laser 10 is deteriorated or short-circuited, the energization path can be disconnected by the fuse portion 302, so that propagation of characteristic deterioration to other elements is blocked. be able to. Therefore, the reliability unique to each surface emitting laser 10 can be maintained, and in addition, high reliability of the laser module can be achieved by the operation described in the first and second embodiments.

  In the present embodiment, the configuration of FIG. 9 can be obtained by the same process steps as those of the first embodiment described with reference to FIG. Here, the difference is that the formation of the upper electrode 8 in FIGS. 6B, 6C and 7A is repeated twice, and the energization electrode and the fuse portion 302 are formed separately. In the point. The material of the fuse portion 302 is formed of, for example, Al (the disconnection current value is defined by the line width), but any material is applicable as long as it has a fuse function.

(V) Fifth Embodiment A fifth embodiment of the laser module according to the present invention will be described with reference to FIGS. The difference from the fourth embodiment shown in FIG. 9 is that, as shown in FIG. 10, the fuse portion 302 is collectively formed on the surface of each surface emitting laser 10-1, and the structure is made of metal. This is a reversible switch by applying a voltage utilizing an oxidation-reduction action.

The configuration and characteristics of this reversible switch will be described with reference to FIG. FIG. 11A is a configuration diagram thereof. For example, it consists of a metal multilayer structure of Cu, Cu ₂ S and Ti. In the initial state, the energization path is formed. This pathway is formed by dissolving metal Cu as Cu + in Cu ₂ S and causing a reduction reaction on the surface of the metal Ti to precipitate Cu + in Cu ₂ S as metal Cu, thereby forming a metal bridge. realizable. When the surface emitting laser 10 is suddenly deteriorated during use in this energized state, the voltage applied to the switch rapidly rises and the switch is turned off. This occurs because metal bridges disappear due to the reverse phenomenon (oxidation). An example of the operating characteristics of the switch when a voltage is applied is shown in FIG.

The constituent material of the reversible switch has been described using a metal multilayer structure of Cu, Cu ₂ S and Ti, but any material can be applied as long as it has the same effect.

(VI) Sixth Embodiment The sixth and seventh embodiments of the laser module according to the present invention will be described with reference to FIG. The basic configuration is that the light source is composed of a plurality of surface-emitting lasers 10. However, if the light emitting portion is arranged in a range of at least a diameter of 100 μm and the number of surface-emitting lasers 10 integrated is as large as possible. The gap between adjacent elements becomes narrow, and a new problem arises in terms of its configuration and element characteristics. The configuration for avoiding this is the sixth embodiment.

  That is, until the fifth embodiment, the surface emitting laser 10 has a cylindrical structure. However, in this structure, heat generated in the active layer is difficult to be transmitted to the air and tends to be stored in the cylindrical structure. There is. As a result, the temperature inside the device increases, and it works to promote the growth of crystal defects.

  FIG. 12 is a top view when the four surface emitting lasers 10 are integrated. Instead of the cylindrical structure, a so-called planar structure is used, and a trench (groove) 304 is formed in order to form an oxidized constriction layer, and the structure can be oxidized in the horizontal direction (the paper surface direction in FIG. 12). Yes. Since the semiconductor layer is continuous in the horizontal direction in the portion other than the trench, the heat is diffused through this portion, and the active layer temperature of the surface emitting laser 10 can be reduced. Thereby, the reliability of an element can be improved. Further, the trench 304 is shared between adjacent elements. This has the following two effects. One is to reduce the area of the oxide layer and the semiconductor interface. Stress strain during this period is one of the main causes of introducing crystal defects, and the reduction in the number of trenches 304 has the effect of reducing the area. Another is that the number of surface emitting lasers can be increased by saving space.

  The sixth embodiment is characterized in that the length of each trench 304 is longer than the emission diameter of the surface emitting laser and functions as an element isolation structure. This element isolation structure has an effect of blocking the heat generated from one light emission diameter 303 from being connected to the adjacent light emission diameter 303 by a straight line and suppressing the occurrence of thermal crosstalk. Thus, as in the second embodiment, even when the plurality of surface emitting lasers 10 are simultaneously driven and the surface emitting lasers 10 are arranged at a high density, the thermal interference can be cut off. The reliability as 10 can be kept high.

(VII) Seventh Embodiment A seventh embodiment of the laser module according to the present invention will be described with reference to FIG. A difference from FIG. 12 is that a plurality of holes 305 arranged on the outer periphery of the light emitting portion 303 of the surface emitting laser are formed for oxidation except for the trench 304 between adjacent elements. As described above, the heat generated in the active layer of the surface emitting laser 10 does not interfere with the heat from the adjacent surface emitting laser 10 and the generated heat is diffused quickly from the viewpoint of device reliability. is important. The advantages of using the shared trench 304 between adjacent elements have been described above. Other than that, a planar structure is desirable as much as possible to promote heat dissipation. Therefore, the request is made possible by arranging the hole 305.

The first to seventh embodiments have been described above. However, the present invention is not limited to the configurations and methods specifically shown in these embodiments, and various variations are conceivable as long as they are within the spirit of the invention. For example, in the above-described embodiment, non-doped GaAs or non-doped Al _0.2 Ga _0.8 As is used as the material of the active layer. However, the present invention is not limited to these, and GaAs or InGaAs is used for near infrared. The optical communication light source can also be configured, and can also be applied to visible light sources such as InGaP and AlGaInP.

  In addition, a long wave band light source can be configured using InGaAsP on an InP substrate, GaInNAs, GaAsSb, or the like on a GaAs substrate, and further, a blue or ultraviolet light source can be configured using a GaN system, a ZnSe system, or the like. be able to.

  In addition, it goes without saying that the material and composition of other layers including the DBR layer and the thickness of each layer including the number of periods of the DBR layer can be appropriately selected and set according to the materials of these active layers.

  In the laser modules of the first to seventh embodiments of the present invention, the oxidized region of the current confinement portion is configured to oxidize aluminum (Al), but is not limited to Al, and is not oxidized when oxidized. Any material can be used as long as the electrical resistance is significantly increased as compared with the region (desirably, an insulator is used) and oscillation of high-order transverse mode light can be reduced.

It is sectional drawing of the conventional surface emitting laser. It is sectional drawing of the conventional laser diode module. It is sectional drawing (a) of the surface emitting laser single-piece | unit of the laser module which is the 1st and 2nd embodiment of this invention, and the top view (b) of the form which integrated the surface emitting laser 4 element. It is sectional drawing of the laser module which is the 1st and 2nd embodiment of this invention. It is a schematic diagram (I) which shows the manufacturing process of the surface emitting laser part in the 1st and 2nd embodiment of this invention. It is a schematic diagram (II) which shows the manufacturing process of the surface emitting laser part in the 1st and 2nd embodiment of this invention. It is a schematic diagram (III) which shows the manufacturing process of the surface emitting laser part in the 1st and 2nd embodiment of this invention. It is sectional drawing of the laser module which is the 3rd Embodiment of this invention. It is a top view of the site | part of the integrated surface emitting element which is the 4th Embodiment of this invention. It is sectional drawing of the surface emitting laser single-piece | unit of the laser module which is the 5th Embodiment of this invention. It is sectional drawing (a) of the reversible switch in the surface emitting laser of the laser module which is the 5th Embodiment of this invention, and the figure (b) explaining operation | movement of a reversible switch. It is a top view of the form which integrated the surface emitting laser of the laser module which is the 6th Embodiment of this invention. It is a top view of the form which integrated the surface emitting laser of the laser module which is the 8th Embodiment of this invention.

Explanation of symbols

1, 1011 Substrate 2 First DBR layer 3 First clad layer 4 Active layer 5 Second clad layer 6 Oxidation current confinement portion formation layer (current confinement layer)
6-1 Non-oxidized region 7 Second DBR layer 8, 1101 Upper electrode 9, 1111 Lower electrode 10 Surface emitting laser (single unit)
DESCRIPTION OF SYMBOLS 11 Upper electrode pad 12 Lower electrode pad 13 Integrated surface emitting laser 14 Bump electrode 15 Flexible substrate 16, 2100 Optical fiber 17, 2101, Core 18, 2201 Laser module 19, 2215 Control circuit 20, 2216 Switching circuit 22-1, 22-2 Photoresist 301 Monitor (PD)
302 Fuse part 303 Emission diameter of surface emitting laser 304 Trench 305 Hole 1021 Lower reflector structure 1031 Lower cladding layer 1041 Light emitting layer 1051 Upper cladding layer 1061 AlAs layer 1062 Oxide layer 1071 Upper reflector structure 2211, 2122 LD
2213, 2214 PD
2217 Current adding circuit 2218 Optical component

Claims (7)

In a light source for optical communication that emits laser light used for optical communication of at least a bandwidth of 5 Gbps (bit per second),
A plurality of vertical cavity surface emitting lasers arranged to be integrated within a range of at least 100 μm in diameter and each emitting the laser beam;
Monitoring means for monitoring the output of the laser light emitted from any of the surface emitting lasers;
Determination means for determining a state of deterioration in each of the surface emitting lasers based on a monitoring result by the monitoring means;
Switching driving means for sequentially switching and driving each of the surface emitting lasers one by one based on the determined deterioration state;
A light source for optical communication, comprising: In a light source for optical communication that emits laser light used for optical communication of at least a bandwidth of 5 Gbps or more,
A plurality of vertical cavity surface emitting lasers arranged in an integrated manner within a range of at least 100 μm in diameter, each emitting the laser beam;
Monitoring means for monitoring the output of the laser light emitted from any of the surface emitting lasers;
Determination means for determining a state of deterioration in each of the surface emitting lasers based on a monitoring result by the monitoring means;
Switching drive means for simultaneously driving at least two or more of each of the surface emitting lasers based on the determined deterioration state, wherein the output value of each of the driven surface emitting lasers is a preset value Switching drive means for driving each of the surface-emitting lasers while suppressing the following and holding the sum of the output values above a value that enables optical communication in the band;
A light source for optical communication, comprising: The light source for optical communication according to claim 1 or 2,
An optical communication characterized in that the monitoring means has a light receiving area capable of monitoring the output values of all the surface emitting lasers, and is disposed on the opposite side of the light emitting side of each surface emitting laser. Light source. In the light source for optical communications according to any one of claims 1 to 3,
A light source for optical communication, wherein drive electrodes of the plurality of surface emitting lasers are independently formed, and fuse means are formed on energization paths respectively corresponding to the drive electrodes. The light source for optical communication according to claim 4,
A light source for optical communication, wherein the fuse means is formed by a reversible switch by voltage application utilizing a metal oxidation-reduction action. In the light source for optical communications according to any one of claims 1 to 5,
Each of the surface emitting lasers includes a first conductivity type DBR (Distributed Bragg Reflector) layer, an active layer, and a second conductivity type DBR layer sequentially stacked on a first conductivity type substrate, and a current constriction portion It is arranged between one of the first conductivity type DBR layer or the second conductivity type DBR layer and the active layer, and
The current confinement portion is formed of an oxide layer that is oxidized from an end face of a trench formed between adjacent surface emitting lasers in a direction perpendicular to the laser light emission direction,
Furthermore, the said trench is provided with the element isolation structure which interrupts | blocks the crystal defect multiplication between each said surface emitting laser, The light source for optical communications characterized by the above-mentioned. The light source for optical communication according to claim 6,
The oxide layer is formed of the oxide layer oxidized in the perpendicular direction from an end face of the trench and an end face of a hole formed by etching from the surface of the surface emitting laser. light source.

Images