Semiconductor laser device and drive control method for a semiconductor laser device

A semiconductor laser device comprising:

• a semiconductor laser element;
• a temperature measuring element to measure a temperature of said semiconductor laser element;
• a temperature regulating unit thermally connected to said semiconductor element and said temperature measuring element;
• a means for detecting a driving current applied to said semiconductor laser element;
• and
• a means for controlling said temperature regulating unit using a control function to achieve a substantially constant wavelength output from said semiconductor laser element, such that the temperature detected by said temperature measuring element substantially equals the predetermined temperature corresponding to the detected driving current as defined by said control function,
• wherein said means for controlling is electrically connected to said temperature measuring element said temperature regulating unit, and said means detecting, and
• wherein said semiconductor laser element includes a diffraction grating to oscillate plural longitudinal modes.

A drive control method for a semiconductor laser device, the method comprising the steps of:

• determining a control function defined as a relationship between a predetermined driving current and a predetermined temperature to achieve a substantially constant wavelength output from a semiconductor laser element of the semiconductor laser device;
• detecting a driving current applied to the semiconductor laser element;
• and
• controlling a temperature regulating unit such that a temperature of the semiconductor laser element detected by a temperature measuring element substantially equals the predetermined temperature corresponding to the detected driving current as defined by the control function,
• wherein the semiconductor laser element and the temperature measuring element are thermally connected to the temperature regulating unit, and
• wherein the semiconductor laser element includes a diffraction grating to oscillate plural longitudinal modes.

A drive control method for a semiconductor laser device for controlling a temperature of a semiconductor laser element on a basis of a temperature of the semiconductor laser element detected by a temperature measuring element disposed near the semiconductor laser element thereby controlling a wavelength of a laser beam oscillated by the semiconductor laser element, wherein the semiconductor laser element includes a diffraction grating to oscillate plural longitudinal modes, the method comprising the steps of:

• detecting a driving current applied to the semiconductor laser element;
• acquiring a relationship between driving current and temperature at which the wavelength of the laser beam oscillated by the semiconductor laser element is generally constant;
• and
• controlling the temperature of the semiconductor laser element so that the detected temperature of the semiconductor laser element and the corresponding detected driving current satisfy the acquired relationship.

A drive control method for a semiconductor laser device for controlling a temperature of a semiconductor laser element on a basis of a temperature of the semiconductor laser element detected by a temperature measuring element disposed near the semiconductor laser element thereby controlling a wavelength of a laser beam oscillated by the semiconductor laser element, wherein the semiconductor laser element includes a diffraction grating to oscillate plural longitudinal modes, the method comprising the steps of:

• detecting a driving current applied to the semiconductor laser element;
• acquiring a plurality of relationships between driving current and temperature in which the wavelength of the laser beam oscillated by the semiconductor laser element is generally constant;
• setting a desired wavelength;
• changing from a present relationship to a new relationship corresponding to the desired wavelength;
• and
• controlling a temperature of the semiconductor laser element so that the detected temperature and the corresponding detected driving current satisfy the new relationship.

A semiconductor laser device comprising:

• a semiconductor laser element;
• a temperature measuring element to measure a temperature of said semiconductor laser element;
• a mounting structure having a first portion thermally connected to said semiconductor laser element, said mounting structure having a second portion thermally connected to said temperature measuring element, whereby said temperature measuring element indirectly measures a temperature of said semiconductor laser element via heat transfer through said mounting structure;
• a temperature regulating unit thermally connected to said mounting structure;
• a current detecting unit to detect a driving current applied to said semiconductor laser element;
• and
• a control unit to control said temperature regulating unit by a control function to achieve a substantially constant wavelength output from said semiconductor laser element, said control function defining a relationship between a predetermined driving current and a predetermined temperature, said control unit being electrically connected to said temperature measuring element, said temperature regulating unit, and said current detecting unit to control said temperature regulating unit such that the temperature detected by said temperature measuring element substantially equals the predetermined temperature corresponding to the detected driving current as defined by said control function.

A semiconductor laser device comprising:

• a semiconductor laser element;
• a temperature measuring element to measure a temperature of said semiconductor laser element;
• a mounting structure having a first portion thermally connected to said semiconductor laser element, said mounting structure having a second portion thermally connected to said temperature measuring element, whereby said temperature measuring element indirectly measures a temperature of said semiconductor laser element via heat transfer through said mounting structure;
• a temperature regulating unit thermally connected to said mounting structure;
• a means for detecting a driving current applied to said semiconductor laser element;
• and
• a means for controlling said temperature regulating unit using a control function to achieve a substantially constant wavelength output from said semiconductor laser element,
• wherein said means for controlling is electrically connected to said temperature measuring element, said temperature regulating unit, and said means for detecting.

A drive control method for a semiconductor laser device, the method comprising the steps of:

• determining a control function defined as a relationship between a predetermined driving current and a predetermined temperature to achieve a substantially constant wavelength output from a semiconductor laser element of the semiconductor laser device;
• detecting a driving current applied to the semiconductor laser element;
• and
• controlling a temperature regulating unit such that a temperature of the semiconductor laser element detected by a temperature measuring element substantially equals the predetermined temperature corresponding to the detected driving current as defined by the control function,
• wherein the semiconductor laser element is thermally connected to a first portion of a mounting structure and the temperature measuring element is thermally connected to a second portion of the mounting structure, and wherein the temperature regulating unit is thermally connected to the mounting structure, whereby the temperature measuring element indirectly measures the temperature of the semiconductor laser element via heat transfer through the mounting structure.

A drive control method for a semiconductor laser device for controlling a temperature of a semiconductor laser element on a basis of a temperature of the semiconductor laser element indirectly detected by a temperature measuring element disposed near the semiconductor laser element via heat transfer through a mounting structure thermally connected to both the semiconductor laser element and the temperature measuring element thereby controlling a wavelength of a laser beam oscillated by the semiconductor laser element, the method comprising the steps of:

• detecting a driving current applied to the semiconductor laser element;
• acquiring a relationship between driving current and temperature at which the wavelength of the laser beam oscillated by the semiconductor laser element is generally constant;
• and
• controlling the temperature of the semiconductor laser element so that the detected temperature of the semiconductor laser element and the corresponding detected driving current satisfy the acquired relationship.

A drive control method for a semiconductor laser device for controlling a temperature of a semiconductor laser element on a basis of a temperature of the semiconductor laser element indirectly detected by a temperature measuring element disposed near the semiconductor laser element via heat transfer through a mounting structure thermally connected to both the semiconductor laser element and the temperature measuring element thereby controlling a wavelength of a laser beam oscillated by the semiconductor laser element, the method comprising the steps of:

• detecting a driving current applied to the semiconductor laser element;
• acquiring a plurality of relationships between driving current and temperature in which the wavelength of the laser beam oscillated by the semiconductor laser element is generally constant;
• setting a desired wavelength;
• changing from a present relationship to a new relationship corresponding to the desired wavelength;
• and
• controlling a temperature of the semiconductor laser element so that the detected temperature and the corresponding detected driving current satisfy the new relationship.