Patent ID: 11967802
Assignee: MITSUBISHI ELECTRIC CORPORATION
Field: Optics (Instruments)
Classification: CPC H | IPC H

Claim 0:
1. A semiconductor laser device comprising:
a semiconductor substrate;
a first conductive type cladding layer provided on the semiconductor substrate;
an active layer provided on the first conductive type cladding layer; and
a second conductive type cladding layer provided on the active layer, wherein
the active layer comprises:
an active region extending in a laser beam emitting direction and having a predetermined width in a width direction perpendicular to the laser beam emitting direction;
a pair of first refractive index regions provided adjacent to the active region in the width direction and extending on both sides of the active region; and
a pair of second refractive index regions sandwiching the active region and the pair of first refractive index regions from outside the pair of the first refractive index regions in the width direction, and
assuming that λ is a laser oscillation wavelength, na is an effective refractive index of the active region, nc is an effective refractive index of the first refractive index region, nt is an effective refractive index of the second refractive index region, w is the predetermined width of the active region and m+1 is an allowable number of modes in the width direction, the semiconductor laser device satisfies:, n
      a
    
    >
    
      n
      t
    
    >
    
      
        n
        c
      
      ⁢
      
        
      
      ⁢
      
        and
        ⁢
        
          

        
        (
        
          
            2
            ⁢
            π
          
          λ
        
        )
      
      ⁢
      
        
          
            n
            
              a
              2
            
          
          -
          
            n
            c
            2
          
        
      
      ⁢
      
        (
        
          w
          2
        
        )
      
    
    >
    
      π
      2
    
  

  
    
      m
      ·
      
        π
        2
      
    
    ≦
    
      
        [
        
          
            2
            ⁢
            π
          
          λ
        
        ]
      
      ⁢
      
        
          
            
              n
              a
              2
            
            -
            
              n
              
                c
                2
              
            
          
        
        ⁡
        
          [
          
            w
            2
          
          ]
        
      
    
    <
    
      
        (
        
          m
          +
          1
        
        )
      
      ·
      
        π
        2
      
    
  

  
    
      
        
          n
          c
          2
        
        +
        
          
            [
            
              λ
              
                2
                ⁢
                w
              
            
            ]
          
          2
        
      
    
    ≦
    nt
    ≦
    
      
        
          
            n
            c
            2
          
          +
          
            
              
                m
                2
              
              [
              
                λ
                
                  2
                  ⁢
                  w
                
              
              ]
            
            2
          
        
      
      .