A semiconductor light emitting device has in sequence on a semiconductor substrate,
a multilayer reflection film, a semiconductor layer, and a quantum well active
layer. A distance between an upper surface of the multilayer reflection film and
a lower surface of the quantum well active layer is 2/n or less, where
is a light emission wavelength and n is an average refractive index of the semiconductor
layer disposed in between the multilayer reflection film and the quantum well active
layer. A phase difference between a reflected ray of light reflected by the multilayer
reflection film and an emitted ray of light from the quantum well active layer
is a multiple of 2. The semiconductor light emitting device stably obtains
a specified peak wavelength even when there is slight variance in the distance
between the upper surface of the multilayer reflection film and the lower surface
of the quantum well active layer.
