Semiconductor optical modulator, an optical amplifier and an integrated semiconductor light-emitting device

Abstract

An integrated semiconductor optical-emitting device includes a surface-emission laser diode and an EA-type semiconductor optical modulator integrated commonly on a GaAs substrate in a direction perpendicular to the GaAs substrate.

1 . A semiconductor optical modulator, comprising: 
 an optical absorption layer of a multiple quantum well structure; and    a p-type electrode and an n-type electrode applying an electric field to said optical absorption layer,    said multiple quantum well structure comprising a quantum layer and a barrier layer,    said quantum well layer being formed of a material selected from the group consisting of: GaNAs, GaInNAs, GaNAsSb and GaInNAsSb,    said barrier layer being formed of a material selected from the group consisting of: GaAs, GaInP and GaInAsP.    
     
     
         2 . A semiconductor optical modulator comprising: 
 an optical absorption layer of multiple quantum well structure; and    p-type and n-type electrodes for applying an electric field to the multiple quantum well structure,    said multiple quantum well structure comprising a quantum well layer, a barrier layer, and an intermediate layer disposed between said quantum well layer and said barrier layer,    said quantum well layer being formed of a material selected from the group consisting of: GaNAs, GaInNAs, GaNAsSb and GaInNAsSb;    said barrier layer being formed of a material selected from the group consisting of: AlaGa1-aAs (0<a.ltoreq.1), (AlbGa1-b) InP (0<b.ltoreq.1) (AlcGa1-c) InAsP (0<c.ltoreq.1),    said intermediate layer comprising a material selected from the group consisting of: GaAs, GaInP and GaInAsP.    
     
     
         3 . An integrated semiconductor light-emitting device, comprising: 
 a semiconductor optical modulator; and    a laser diode having an active layer of any of GaNAs, GaInNAs, GaNAsSb and GaInNAsSb,    said semiconductor optical modulator and said laser diode being integrated on a common substrate,    said semiconductor optical modulator, comprising:    an optical absorption layer of a multiple quantum well structure; and    a p-type electrode and an n-type electrode applying an electric field to said optical absorption layer,    said multiple quantum well structure comprising a quantum layer and a barrier layer,    said quantum well layer being formed of a material selected from the group consisting of: GaNAs, GaInNAs, GaNAsSb and GaInNAsSb,    said barrier layer being formed of a material selected from the group consisting of: GaAs, GaInP and GaInAsP.    
     
     
         4 . An integrated semiconductor light-emitting device as claimed in  claim 3 , wherein said laser diode and said semiconductor are formed monolithically on said substrate.  
     
     
         5 . An integrated semiconductor light-emitting device as claimed in  claim 3 , wherein said laser diode is a surface-emission laser diode.  
     
     
         6 . An integrated semiconductor light-emitting device as claimed in  claim 5 , wherein said surface-emission laser diode and said semiconductor optical modulator are integrated monolithically in a direction perpendicular to said substrate.  
     
     
         7 . An integrated semiconductor light-emitting device as claimed in  claim 6 , wherein said semiconductor optical modulator is provided inside an optical cavity of said surface-emission laser diode.  
     
     
         8 . An integrated semiconductor light-emitting device as claimed in  claim 6 , wherein said semiconductor optical modulator is provided inside a distributed Bragg reflector of said surface-emission laser diode.  
     
     
         9 . An integrated semiconductor light-emitting device as claimed in  claim 6 , wherein said semiconductor optical modulator is provided inside a distributed Bragg reflector of located near said substrate with respect to said active layer.  
     
     
         10 . An integrated semiconductor light-emitting device, comprising: 
 a semiconductor optical modulator; and    a laser diode having an active layer of any of GaNAs, GaInNAs, GaNAsSb and GaInNAsSb,    said semiconductor optical modulator and said laser diode being integrated on a common substrate,    said semiconductor optical modulator, comprising:    an optical absorption layer of multiple quantum well structure; and    p-type and n-type electrodes for applying an electric field to the multiple quantum well structure,    said multiple quantum well structure comprising a quantum well layer, a barrier layer, and an intermediate layer disposed between said quantum. well layer and said barrier layer,    said quantum well layer being formed of a material selected from the group consisting of: GaNAs, GaInNAs, GaNAsSb and GaInNAsSb;    said barrier layer being formed of a material selected from the group consisting of: AlaGa1-aAs (0<a.ltoreq.1), (AlbGa1-b) InP (0<b.ltoreq.1) (AlcGa1-c) InAsP (0<c.ltoreq.1),    said intermediate layer comprising a material selected from the group consisting of: GaAs, GaInP and GaInAsP.    
     
     
         11 . An integrated semiconductor light-emitting device as claimed in  claim 10 , wherein said laser diode is a surface-emission laser diode.  
     
     
         12 . An integrated semiconductor light-emitting device as claimed in  claim 11 , wherein said surface-emission laser diode and said semiconductor optical modulator are integrated monolithically in a direction perpendicular to said substrate.  
     
     
         13 . An integrated semiconductor light-emitting device as claimed in  claim 12 , wherein said semiconductor optical modulator is provided inside an optical cavity of said surface-emission laser diode.  
     
     
         14 . An integrated semiconductor light-emitting device as claimed in  claim 12 , wherein said semiconductor optical modulator is provided inside a distributed Bragg reflector of said surface-emission laser diode.  
     
     
         15 . An integrated semiconductor light-emitting device as claimed in  claim 12 , wherein said semiconductor optical modulator is provided inside a distributed Bragg reflector of located near said GaAs substrate with respect to said active layer.  
     
     
         16 - 21 . (canceled)  
     
     
         22 . A tunable laser apparatus, comprising: 
 an optical cavity having a pair of reflectors;    an amplitude spontaneous emission optical radiation source provided in said optical cavity;    a wavelength divide filter provided in said optical cavity, said wavelength divide filter splitting an optical radiation produced by said amplitude spontaneous optical emission optical source into optical radiation components having respective wavelengths;    an optical gate array provided in said optical cavity, said optical gate array selectively amplifying an optical radiation component divided by said wavelength divide filter; and    a semiconductor optical modulator modulating an intensity of said optical radiation component passed through said optical gate array,    said semiconductor optical modulator comprising:    an optical absorption layer of a multiple quantum well structure; and    a p-type electrode and an n-type electrode applying an electric field to said optical absorption layer,    said multiple quantum well structure comprising a quantum well layer and a barrier layer,    said quantum well layer being formed of a material selected from the group consisting of: GaNAs, GaInNAs, GaNAsSb and GaInNAsSb,    said barrier layer being formed of a material selected from the group consisting of: GaAs, GaInP and GaInAsP.    
     
     
         23 . A tunable laser apparatus, comprising: 
 an optical cavity having a pair of reflectors;    an amplitude spontaneous emission optical radiation source provided in said optical cavity;    a wavelength divide filter provided in said optical cavity, said wavelength divide filter splitting an optical radiation produced by said amplitude spontaneous optical emission optical source into optical radiation components having respective wavelengths;    an optical gate array provided in said optical cavity, said optical gate array selectively amplifying an optical radiation component divided by said wavelength divide filter; and    a semiconductor optical modulator modulating an intensity of said optical radiation component passed through said optical gate array,    said semiconductor optical modulator comprising:    an optical absorption layer of multiple quantum well structure; and    p-type and n-type electrodes for applying an electric field to the multiple quantum well structure,    said multiple quantum well structure comprising a quantum well layer, a barrier layer, and an intermediate layer disposed between said quantum well layer and said barrier layer,    said quantum well layer being formed of a material selected from the group consisting of: GaNAs, GaInNAs, GaNAsSb and GaInNAsSb;    said barrier layer being formed of a material selected from the group consisting of: AlaGa1-aAs (0<a.ltoreq.1), (AlbGa1-b) InP (0<b.ltoreq.1) (AlcGa1-c) InAsP (0<c.ltoreq.1),    said intermediate layer comprising a material selected from the group consisting of: GaAs, GaInP and GaInAsP.    
     
     
         24 . A multi-wavelength laser apparatus, comprising: 
 an optical cavity including a pair of reflectors;    an wavelength divide filter provided in said optical cavity;    a semiconductor optical amplifier provided in said optical cavity for selectively amplifying an optical radiation divided by said wavelength divide filter; and    a semiconductor optical modulator provided in said optical cavity, said semiconductor optical modulator modulating an intensity of said optical radiation divided by said semiconductor optical amplifier,    said semiconductor optical modulator comprising:    an optical absorption layer of a multiple quantum well structure; and    a p-type electrode and an n-type electrode applying an electric field to said optical absorption layer,    said multiple quantum well structure comprising a quantum layer and a barrier layer,    said quantum well layer being formed of a material selected from the group consisting of: GaNAs, GaInNAs, GaNAsSb and GaInNAsSb,    said barrier layer being formed of a material selected from the group consisting of: GaAs, GaInP and GaInAsP.    
     
     
         25 . A multi-wavelength laser apparatus, comprising: 
 an optical cavity including a pair of reflectors;    an wavelength divide filter provided in said optical cavity;    a semiconductor optical amplifier provided in said optical cavity for selectively amplifying an optical radiation divided by said wavelength divide filter; and    a semiconductor optical modulator provided in said optical cavity, said semiconductor optical modulator modulating an intensity of said optical radiation divided by said semiconductor optical amplifier,    said semiconductor optical modulator comprising:    an optical absorption layer of multiple quantum well structure; and    p-type and n-type electrodes for applying an electric field to the multiple quantum well structure,    said multiple quantum well structure comprising a quantum well layer, a barrier layer, and an intermediate layer disposed between said quantum well layer and said barrier layer,    said quantum well layer being formed of a material selected from the group consisting of: GaNAs, GaInNAs, GaNAsSb and GaInNAsSb;    said barrier layer being formed of a material selected from the group consisting of: AlaGa1-aAs (0<a.ltoreq.1), (AlbGa1-b) InP (0<b.ltoreq.1), (AlcGa1-c) InAsP (0<c.ltoreq.1),    said intermediate layer comprising a material selected from the group consisting of: GaAs, GaInP and GaInAsP.    
     
     
         26 . An optical transmission system, comprising: 
 an optical transmission module producing optical signals of respective wavelengths;    an optical fiber transmitting said optical signals produced by said optical transmission module; and    an optical receiver module receiving said optical signals transmitted through said optical fiber,    said optical transmission module comprising a multi-wavelength laser apparatus, said multi-wavelength laser apparatus comprising:    an optical cavity including a pair of reflectors;    a wavelength divide filter provided in said optical cavity;    a semiconductor optical amplifier provided in said optical cavity for selectively amplifying an optical radiation divided by said wavelength divide filter; and    a semiconductor optical modulator provided in said optical cavity, said semiconductor optical modulator modulating an intensity of said optical radiation divided by said semiconductor optical amplifier,    said semiconductor optical modulator comprising:    an optical absorption layer of a multiple quantum well structure; and    a p-type electrode and an n-type electrode applying an electric field to said optical absorption layer,    said multiple quantum well structure comprising a quantum well layer and a barrier layer,    said quantum well layer being formed of a material selected from the group consisting of: GaNAs, GaInNAs, GaNAsSb and GaInNAsSb,    said barrier layer being formed of a material selected from the group consisting of: GaAs, GaInP and GaInAsP.    
     
     
         27 . An optical transmission system, comprising: 
 an optical transmission module producing optical signals of respective wavelengths;    an optical fiber transmitting said optical signals produced by said optical transmission module; and    an optical receiver module receiving said optical signals transmitted through said optical fiber,    said optical transmission module comprising a multi-wavelength laser apparatus, said multi-wavelength laser apparatus comprising:    an optical cavity including a pair of reflectors;    an wavelength divide filter provided in said optical cavity;    a semiconductor optical amplifier provided in said optical cavity for selectively amplifying an optical radiation divided by said wavelength divide filter; and    a semiconductor optical modulator provided in said optical cavity, said semiconductor optical modulator modulating an intensity of said optical radiation divided by said semiconductor optical amplifier,    said semiconductor optical modulator comprising:    an optical absorption layer of multiple quantum well structure; and    p-type and n-type electrodes for applying an electric field to the multiple quantum well structure,    said multiple quantum well structure comprising a quantum well layer, a barrier layer, and an intermediate layer disposed between said quantum well layer and said barrier layer,    said quantum well layer being, formed of a material selected from the group consisting of: GaNAs, GaInNAs, GaNAsSb and GaInNAsSb;    said barrier layer being formed of a material selected from the group consisting of: AlaGa1-aAs (0<a.ltoreq.1), (AlbGa1-b) InP (0<b.ltoreq.1), (AlcGa1-c) InAsP (0<c.ltoreq.1),    said intermediate layer comprising a material selected from the group consisting of: GaAs, GaInP and GaInAsP.    
     
     
         28 . A semiconductor optical amplifier, comprising: 
 a GaAs substrate;    a gain region formed on said GaAs substrate; and    p-side and an n-side electrodes for injecting electric current into said gain region,    said gain region comprising a semiconductor layer selected from the group consisting of: GaNAs, GaInNAs, GaNAsSb and GaInNAsSb.    
     
     
         29 . A semiconductor optical amplifier as claimed in  claim 28 , wherein said gain region has a multiple quantum well structure including a stacking of plurality quantum well layers, each of said quantum well layers having a composition selected from the group consisting of GaNAs, GaInNAs, GaNAsSb and GaInNAsSb, said quantum well layers having respective bandgaps different from each other.  
     
     
         30 . A semiconductor optical amplifier as claimed in  claim 28 , wherein said semiconductor optical amplifier further comprises means for suppressing laser oscillation in a Fabri-Perot mode.  
     
     
         31 . An amplitude spontaneous emission optical source, comprising: 
 a GaAs substrate; a gain region formed on said GaAs substrate; and    p-side and an n-side electrodes for injecting electric current into said gain region,    said gain region comprising a semiconductor layer selected from the group consisting of: GaNAs, GaInNAs, GaNAsSb and GaInNAsSb.    
     
     
         32 . An optical gate array, comprising: 
 a GaAs substrate; and    a plurality of optical semiconductor amplifiers formed on said GaAs substrate in the form of an array, each of said optical semiconductor amplifiers comprising:    a gain region formed on said GaAs substrate; and    p-side and an n-side electrodes for injecting electric current into said gain region,    said gain region comprising a semiconductor layer selected from the group consisting of: GaNAs, GaInNAs, GaNAsSb and GaInNAsSb.    
     
     
         33 . A tunable laser apparatus, comprising: 
 an optical cavity having a pair of reflectors;    an amplitude spontaneous emission optical source provided in said optical cavity;    a wavelength divide filter provided in said optical cavity, said wavelength divide filter dividing an optical beam produced by said amplitude spontaneous emission optical source into optical beam components of respective wavelengths; and    an optical gate array provided in said optical cavity, said optical gate array selectively amplifying said optical beam component divided by said wavelength divide filter,    said amplitude spontaneous emission optical source comprising:    a GaAs substrate;    a gain region formed on said GaAs substrate; and    p-side and an n-side electrodes for injecting electric current into said gain region,    said gain region comprising a semiconductor layer selected from the group consisting of: GaNAs, GaInNAs, GaNAsSb and GaInNAsSb,    said optical gate array comprising:    a plurality of optical semiconductor amplifiers formed on said GaAs substrate in the form of an array, each of said optical semiconductor amplifiers comprising:    a gain region formed on said GaAs substrate; and    p-side and an n-side electrodes for injecting electric current into said gain region,    said gain region comprising a semiconductor layer selected from the group consisting of: GaNAs, GaInNAs, GaNAsSb and GaInNAsSb.    
     
     
         34 . A multi-wavelength laser apparatus, comprising: 
 an optical cavity;    a wavelength divide filter provided in said optical cavity; and    a semiconductor optical amplifier provided in said optical cavity, said semiconductor optical amplifier selectively amplifying an optical beam divided by said wavelength divide filter, said semiconductor optical amplifier comprising:    a GaAs substrate;    a gain region formed on said GaAs substrate; and    p-side and an n-side electrodes for injecting electric current into said gain region,    said gain region comprising a semiconductor layer selected from the group consisting of: GaNAs, GaInNAs, GaNAsSb and GaInNAsSb.    
     
     
         35 . A wavelength-division multiplex optical transmission system, comprising: 
 an optical transmission module producing optical signals of respective wavelengths;    an optical fiber transmitting said optical signals produced by said optical transmission module; and    an optical receiver module receiving said plural optical signals from said optical fiber,    said optical transmission module including a semiconductor optical amplifier comprising:    a GaAs substrate;    a gain region formed on said GaAs substrate; and    p-side and an n-side electrodes for injecting electric current into said gain region,    said gain region comprising a semiconductor layer selected from the group consisting of: GaNAs, GaInNAs, GaNAsSb and GaInNAsSb.    
     
     
         36 . A method of fabricating an integrated semiconductor light-emitting device, comprising: 
 a GaAs substrate;    a surface-emission laser diode comprising an optical cavity defined by a pair of distributed Bragg reflectors, said optical cavity including an active layer of a material selected from any of GaNAs, GaInNAs, GaNAsSb and GaInNAsSb; and    a semiconductor optical modulator comprising an optical absorption layer of a material selected from any of GaNAs, GaInNAs, GaNAsSb and GaInNAsSb,    said surface-emission laser diode and said semiconductor optical modulator being integrated on said GaAs substrate monolithically in a direction perpendicular to said GaAs substrate,    said semiconductor optical modulator being provided in any of said optical cavity and said pair of distributed Bragg reflectors,    a part of any of said optical cavity, said pair of distributed Bragg reflectors and said semiconductor optical modulator including a semiconductor layer containing Al,    said method comprising the steps of:    growing a semiconductor layer containing Al by supplying an Al source to a growth chamber; and    growing a semiconductor layer containing N by supplying a nitrogen compound source to said growth chamber,    wherein said method further comprising the step, after said step of growing said semiconductor layer containing Al but before said step of growing said semiconductor layer containing N, of removing any of residual Al source, residual Al reactant, residual Al compound, and residual Al remaining in said growth chamber from a location of said growth chamber where there is a chance of making a contact with said nitrogen source or an impurity contained in said nitrogen source.    
     
     
         37 . An integrated semiconductor light-emitting device, comprising: 
 a GaAs substrate;    a surface-emission laser diode comprising an optical cavity defined by upper and lower distributed Bragg reflectors, said optical cavity including an active layer of a material selected from any of GaNAs, GaInNAs, GaNAsSb and GaInNAsSb; and    a semiconductor optical modulator comprising an optical absorption layer of a material selected from any of GaNAs, GaInNAs, GaNAsSb and GaInNAsSb,    said surface-emission laser diode and said semiconductor optical modulator being integrated on said GaAs substrate monolithically in a direction perpendicular to said GaAs substrate,    said semiconductor optical modulator being provided in any of said optical cavity and said upper distributed Bragg reflector at a level above said active layer,    wherein there is provided a non-optical recombination elimination layer of a material of a system of GaInAsP between said lower distributed Bragg reflector and said optical cavity.    
     
     
         38 . An integrated semiconductor light-emitting device as claimed in  claim 37 , wherein a semiconductor region of said integrated semiconductor light-emitting device located between said active layer and said optical absorption layer is formed of GaInAsP for the entire part thereof.  
     
     
         39 . An integrated semiconductor light-emitting device as claimed in  claim 38 , wherein said region includes an n-type semiconductor layer.  
     
     
         40 . An integrated semiconductor light-emitting device as claimed in  claim 37 , wherein said semiconductor optical modulator is provided inside of said upper distributed Bragg reflector such that said optical absorption layer of said semiconductor optical modulator is provided in a high refractive index layer having an optical thickness of three quarter a wavelength of laser oscillation of said surface-emission layer diode, with an offset of one quarter of said wavelength as measured from a surface of said high refractive index layer located at a side close to said active layer.  
     
     
         41 . An integrated semiconductor light-emitting device as claimed in  claim 40 , further comprising an additional distributed Bragg reflector having a thickness of two periods between said optical absorption layer and said optical cavity such that said additional distributed Bragg reflector including two high refractive index layers and two low refractive index layers repeated alternately, wherein said high refractive index layer located closer to said optical cavity as compared with another high refractive index layer carries thereon an ohmic electrode.  
     
     
         42 . An integrated semiconductor light-emitting device as claimed in  claim 39 , further comprising a pair of selective oxidation layers above and below a region including said optical absorption layer and said active layer.  
     
     
         43 . An integrated semiconductor light-emitting device, comprising: 
 a GaAs substrate;    a surface-emission laser diode comprising an optical cavity defined by upper and lower distributed Bragg reflectors, said optical cavity including an active layer of a material selected from any of GaNAs, GaInNAs, GaNAsSb and GaInNAsSb; and    a semiconductor optical modulator comprising an optical absorption layer of a material selected from any of GaNAs, GaInNAs, GaNAsSb and GaInNAsSb,    said surface-emission laser diode and said semiconductor optical modulator being integrated on said GaAs substrate monolithically in a direction perpendicular to said GaAs substrate,    said semiconductor optical modulator being provided in any of said optical cavity and said lower distributed Bragg reflector at a level below said active layer,    wherein there is provided a non-optical recombination elimination layer of a material of a GaInAsP system between said lower distributed Bragg reflector and said optical absorption layer.    
     
     
         44 . An integrated semiconductor light-emitting device as claimed in  claim 43 , wherein a semiconductor region of said integrated semiconductor light-emitting device located between said active layer and said optical absorption layer is formed of GaInAsP for the entire part thereof.  
     
     
         45 . An integrated semiconductor light-emitting device as claimed in  claim 44 , wherein said region includes an n-type semiconductor layer.  
     
     
         46 . An integrated semiconductor light-emitting device as claimed in  claim 43 , wherein said semiconductor optical modulator is provided inside of said upper distributed Bragg reflector such that said optical absorption layer of said semiconductor optical modulator is provided in a high refractive index layer having an optical thickness of three quarter a wavelength of laser oscillation of said surface-emission layer diode, with an offset of one quarter of said wavelength as measured from a surface of said high refractive index layer located at a side close to said active layer.  
     
     
         47 . An integrated semiconductor light-emitting device as claimed in  claim 46 , further comprising an additional distributed Bragg reflector having a thickness of two periods between said optical absorption layer and said optical cavity such that said additional distributed Bragg reflector including two high refractive index layers and two low refractive index layers repeated alternately, wherein said high refractive index layer located closer to said optical cavity as compared with another high refractive index layer carries thereon an ohmic electrode.  
     
     
         48 . An integrated semiconductor light-emitting device as claimed in  claim 45 , further comprising a pair of selective oxidation layers above and below a region including said optical absorption layer and said active layer.  
     
     
         49 . An optical transmission system, comprising: 
 an integrated semiconductor light-emitting device, comprising: a GaAs substrate; a surface-emission laser diode comprising an optical cavity defined by upper and lower distributed Bragg reflectors, said optical cavity including an active layer of a material selected from any of GaNAs, GaInNAs, GaNAsSb and GaInNAsSb; and a semiconductor optical modulator comprising an optical absorption layer of a material selected from any of GaNAs, GaInNAs, GaNAsSb and GaInNAsSb, said surface-emission laser diode and said semiconductor optical modulator being integrated on said GaAs substrate monolithically in a direction perpendicular to said GaAs substrate,    said semiconductor optical modulator being provided in any of said optical cavity and said upper distributed Bragg reflector at a level above said active layer, wherein there is provided a non-optical recombination elimination layer of a material of a system of GaInAsP between said lower distributed Bragg reflector and said optical cavity;    an optical fiber coupled to said integrated semiconductor light-emitting device at an end thereof; and    an optical receiver coupled to said optical fiber at another end thereof.    
     
     
         50 . An optical transmission system comprising an integrated semiconductor light-emitting device, said integrated semiconductor light-emitting device comprising: a GaAs substrate; a surface-emission laser diode comprising an optical cavity defined by upper and lower distributed Bragg reflectors, said optical cavity including an active layer of a material selected from any of GaNAs, GaInNAs, GaNAsSb and GaInNAsSb; and a semiconductor optical modulator comprising an optical absorption layer of a material selected from any of GaNAs, GaInNAs, GaNAsSb and GaInNAsSb, said surface-emission laser diode and said semiconductor optical modulator being integrated on said GaAs substrate monolithically in a direction perpendicular to said GaAs substrate, said semiconductor optical modulator being provided in any of said optical cavity and said lower distributed Bragg reflector at a level below said active layer, wherein there is provided a non-optical recombination elimination layer of a material of a GaInAsP system between said lower distributed Bragg reflector and said optical absorption layer; 
 an optical fiber coupled to said integrated semiconductor light-emitting device at an end thereof; and    an optical receiver coupled to said optical fiber at another end thereof.    
     
     
         51 . An integrated semiconductor light-emitting device, comprising: 
 a GaAs substrate;    a surface-emission laser diode comprising an optical cavity defined by upper and lower distributed Bragg reflectors, said optical cavity including an active layer of a material selected from any of GaNAs, GaNAsSb and GaInNAsSb; and    a semiconductor optical modulator comprising an optical absorption layer of a material selected from any of GaNAs, GaInNAs, GaNAsSb and GaInNAsSb,    said surface-emission layer diode and said semiconductor optical modulator being integrated on said GaAs substrate monolithically in a direction perpendicular to said GaAs substrate,    said semiconductor optical modulator being provided in any of said optical cavity and said upper distribute Bragg reflector at a level above said active layer.