Semiconductor laser element

A semiconductor laser element including a resonator in which laser light resonates in a first direction between a front-side end face and a rear-side end face, the semiconductor laser element comprising:

• a first conductivity-type cladding layer disposed above a first conductivity-type semiconductor substrate;
• a first guide layer disposed above the first conductivity-type cladding layer;
• an active layer disposed above the first guide layer;
• and
• a second conductivity-type cladding layer disposed above the active layer, wherein
• a window region is formed in a region of the active layer including part of at least one of the front-side end face or the rear-side end face,
• an average composition of the first conductivity-type cladding layer is denoted by (AlxGa1-x)0.5In0.5P, where x denotes an average Al composition ratio,
• the first guide layer includes (AlyGa1-y)0.5In0.5P, where y denotes an Al composition ratio,
• an average composition of the second conductivity-type cladding layer is denoted by (AlzGa1-z)0.5In0.5P, where z denotes an average Al composition ratio,
• 0<x−y<z−y is satisfied,
• D/L>0.03 is satisfied, where L denotes a length of the resonator and D denotes a length of the window region in the first direction,
• the active layer includes a well layer and barrier layers,
• a difference between a composition ratio of the well layer and a composition ratio of the barrier layers in the window region is less than a difference between a composition ratio of the well layer and a composition ratio of the barrier layers in a region other than the window region, and
• a refractive index of the first conductivity-type cladding layer is greater than a refractive index of the barrier layers.

A semiconductor laser element including a resonator in which laser light resonates in a first direction between a front-side end face and a rear-side end face, the semiconductor laser element comprising:

• a first conductivity-type cladding layer disposed above a first conductivity-type semiconductor substrate;
• a first guide layer disposed above the first conductivity-type cladding layer;
• an active layer disposed above the first guide layer;
• and
• a second conductivity-type cladding layer disposed above the active layer, wherein
• a window region is formed in a region of the active layer including part of at least one of the front-side end face or the rear-side end face,
• the first conductivity-type cladding layer includes an (AlxGa1-x)0.5In0.5P layer, where x denotes an Al composition ratio,
• the first guide layer includes (AlyGa1-y)0.5In0.5P, where y denotes an Al composition ratio,
• the second conductivity-type cladding layer includes an (AlzGa1-z)0.5In0.5P layer, where z denotes an Al composition ratio,
• 0<x−y<z−y is satisfied,
• D/L>0.03 is satisfied, where L denotes a length of the resonator and D denotes a length of the window region in the first direction, and
• an impurity concentration of the first conductivity-type semiconductor substrate is higher than an impurity concentration of the first conductivity-type cladding layer.

A semiconductor laser element including a resonator in which laser light resonates in a first direction between a front-side end face and a rear-side end face, the semiconductor laser element comprising:

• a first conductivity-type cladding layer disposed above a first conductivity-type semiconductor substrate;
• a first guide layer disposed above the first conductivity-type cladding layer;
• an active layer disposed above the first guide layer;
• and
• a second conductivity-type cladding layer disposed above the active layer, wherein
• a window region is formed in a region of the active layer including part of at least one of the front-side end face or the rear-side end face,
• the first conductivity-type cladding layer includes an (AlxGa1-x)0.5In0.5P layer, where x denotes an Al composition ratio,
• the first guide layer includes (AlyGa1-y)0.5In0.5P, where y denotes an Al composition ratio,
• the second conductivity-type cladding layer includes an (AlzGa1-z)0.5In0.5P layer, where z denotes an Al composition ratio,
• 0<x−y<z−y is satisfied,
• D/L>0.03 is satisfied, where L denotes a length of the resonator and D denotes a length of the window region in the first direction,
• the active layer includes a well layer and barrier layers,
• a difference between a composition ratio of the well layer and a composition ratio of the barrier layers in the window region is less than a difference between a composition ratio of the well layer and a composition ratio of the barrier layers in a region other than the window region, and
• a refractive index of the first conductivity-type cladding layer is greater than a refractive index of the barrier layers.