Wavelength-changeable light source capable of changing wavelength of output light, optical communication network using the same and wavelength control method for controlling wavelength

A wavelength-changeable light source comprising:

• a semiconductor laser;
• current control means for controlling a lasing wavelength of said semiconductor laser by controlling a current supplied to said semiconductor laser;
• and
• temperature control means for controlling the lasing wavelength of said semiconductor laser by controlling a temperature of said semiconductor laser, wherein control by said current control means of an amount of a chance in the lasing wavelength is replaced by control by said temperature control means of the amount of chance in the lasing wavelength while retaining the amount of change in the lasing wavelength executed by said current control means.

An optical communication network for performing communication by using light, said network comprising:

• a transmission line for transmitting light therethrough;
• and
• a wavelength-changeable light source for outputting light to said transmission line, said light source including:
• a laser;
• first control means for controlling a lasing wavelength of said laser with a first response time;
• and
• second control means for controlling the lasing wavelength of said laser with a response time which is longer than the first response time, wherein control by said first control means of an amount of a change in the lasing wavelength is replaced by control by said second control means of the amount of change in the lasing wavelength while retaining the amount of change in the lasing wavelength executed by said first control means.

An optical communication network for performing communication by using light, said network comprising:

• a transmission line for transmitting light therethrough;
• and
• a wavelength-changeable light source for outputting light to said transmission line, said light source including:
• a semiconductor laser;
• current control means for controlling a lasing wavelength of said semiconductor laser by controlling a current supplied to said semiconductor laser;
• and
• temperature control means for controlling the lasing wavelength of said semiconductor laser by controlling a temperature of said semiconductor laser, wherein control by said current control means of an amount of a change in the lasing wavelength is replaced by control by said temperature control means of the amount of change in the lasing wavelength while retaining the amount of change in the lasing wavelength executed by said current control means.

A wavelength-changeable light source comprising:

• a semiconductor laser;
• current control means for controlling a lasing wavelength of said semiconductor laser by controlling a current supplied to said semiconductor laser;
• and
• temperature control means for controlling the lasing wavelength of said semiconductor laser by controlling a temperature of said semiconductor laser, wherein, after the lasing wavelength is changed by said current control means, control by said current control means of an amount of a change in the lasing wavelength is replaced by control by said temperature control means of the amount of change in the lasing wavelength while retaining the amount of change in the lasing wavelength executed by said current control means.

A wavelength-changeable light source comprising:

• a semiconductor laser;
• current control means for controlling a lasing wavelength of said semiconductor laser by controlling a current supplied to said semiconductor laser;
• and
• temperature control means for controlling the lasing wavelength of said semiconductor laser by controlling a temperature of said semiconductor laser, wherein, after the lasing wavelength is changed by said current control means without performing the control by said temperature control means, control by said current control means of an amount of a change in the lasing wavelength is replaced by control by said temperature control means of the amount of change in the lasing wavelength while retaining the amount of change in the lasing wavelength executed by said current control means.