Optical gain waveguide and method of controlling the same

An optical amplifier comprising:

• an optical gain waveguide having a higher gain than an Al-codoped EDFA at a wavelength of 1,524.5 nm, and also having a relative gain variation of 35% or less at a wavelength band of 1,524.5 nm to 1,557.5 nm;
• and
• a pumping light source supplying pumping light with a specific wavelength into said optical gain waveguide.

An optical amplifier comprising:

• an optical gain waveguide whose optical waveguide region is doped with Er element;
• and
• a pumping light source supplying pumping light with a predetermined wavelength into said optical waveguide region so that a relative gain variation per unit wavelength band becomes 0.3%/nm or less throughout a whole signal wavelength region in a gain spectrum of said optical gain waveguide.

An optical gain waveguide whose optical waveguide region is doped with Er element which can be pumped by irradiating pumping light with a wavelength of 976 nm or less, or a wavelength of 981 nm or more,

• wherein, when the pumping light is irradiated to said optical waveguide region so that a gain variation of said optical gain waveguide in C-band is minimized by optimizing a population inversion of Er in said optical waveguide region, a relative gain variation of said optical gain waveguide, defined by a peak gain value and a minimum gain value at the wavelength band of 1,530 nm to 1,560 nm, becomes smaller than 11.5%.

An optical gain waveguide including an optical waveguide region which is doped with Er element which can be pumped by irradiating pumping light with an optimal wavelength in a 0.98-μm wavelength band,

• wherein, when the pumping light is irradiated to said optical waveguide region so that a gain variation of said optical gain waveguide in C-band is minimized by optimizing a population inversion of Er in said optical waveguide region, a relative gain variation of said optical gain waveguide, defined by the gain produced at a wavelength of 1,524.5 nm and a peak gain value, becomes smaller than 35%.

An optical gain waveguide whose optical waveguide region is doped with Er element which can be pumped by irradiating pumping light with a wavelength band of 1.48 μm,

• wherein, when the pumping light is irradiated to said optical waveguide region so that a gain variation of said optical gain waveguide in C-band is minimized by optimizing a population inversion of Er in said optical waveguide region, a relative gain variation of said optical gain waveguide, defined by a peak gain value and a minimum gain value at a wavelength band of 1,530 nm to 1,560 nm becomes smaller than 12%.

An optical amplifier comprising:

• an optical gain waveguide having a higher gain than an Al-codoped EDFA at a wavelength of 1,524.5 nm, and also having a relative gain variation of 35% or less at a wavelength band of 1,524.5 nm to 1,557.5 nm.

An optical amplifier, comprising an optical gain waveguide whose optical waveguide region is doped with Er element,

• wherein said optical gain waveguide has a gain spectrum in which a relative gain variation per unit wavelength band is 0.3%/nm or less, throughout a whole signal wavelength region.