Optical module, optical apparatus including optical module, and method for using optical module

An optical apparatus comprising:

• an optical module including
• a package,
• an optical device housed in the package and having a temperature-dependent characteristic,
• a temperature sensor disposed in the vicinity of the optical device and configured to detect a temperature of the optical device, and
• a thermo-module connected to the optical device to control the temperature of the optical device and configured to heat or cool the optical device when supplied with a first electric current in one direction or a second electric current in a direction opposite to the first electric current, respectively;
• a thermo-module power supply for supplying an electric current to the thermo-module;
• and
• a control unit for controlling a polarity and an intensity of the electric current from the thermo-module power supply to the thermo-module thereby heating or cooling the optical device based on the temperature of the optical device, the control unit having an overheat prevention function for preventing the optical device from being overheated due to a heating operation of the thermo-module.

A method for using an optical module,

• the optical module including:
• a package;
• an optical device housed in the package and having a temperature-dependent characteristic;
• a temperature sensor disposed in the vicinity of the optical device and configured to detect a temperature of the optical device;
• and
• a thermo-module connected to the optical device to control the temperature of the optical device and configured to heat or cool the optical device when supplied with a first electric current in one direction or a second electric current in a direction opposite to the first electric current, respectively;
• wherein
• the method comprises a preheating step for preliminarily heating the optical device prior to supplying one of the first electric current and the second electric current to the thermo-module, when starting up the optical module.

A method for using an optical module,

• the optical module including:
• a package;
• an optical device housed in the package and having a temperature-dependent characteristic;
• a temperature sensor disposed in the vicinity of the optical device and configured to detect a temperature of the optical device;
• a heating element disposed close to the optical device and configured to generate heat when supplied with an electric current;
• a thermo-module connected to the optical device to control the temperature of the optical device and configured to heat or cool the optical device when supplied with a first electric current in one direction or a second electric current in a direction opposite to the first electric current, respectively;
• wherein
• the method comprises:
• a temperature detection step for detecting a temperature of the optical device during an operation thereof, and
• a temperature control step for supplying the first electric current or second electric current to the thermo-module based on the deviation of the temperature detected in the temperature detection step of the optical device from a predetermined value in order to keep the temperature of the optical device at the predetermined value,
• the temperature control step including a process of supplying an electric current to the heating element when the first electric current is supplied to the thermo-module.

A method for using an optical module,

• the optical module including:
• a package;
• a semiconductor laser housed in the package and having a temperature-dependent characteristic;
• a temperature sensor disposed in the vicinity of the semiconductor laser and configured to detect a temperature of the semiconductor laser;
• a thermo-module connected to the semiconductor laser to control the temperature of the semiconductor laser and configured to heat or cool the semiconductor laser when supplied with a first electric current in one direction or a second electric current in a direction opposite to the first electric current, respectively;
• wherein
• the method comprises:
• an environmental temperature detection step for detecting a temperature of an environment in which the optical module is placed, and
• a temperature control step for supplying one of the first electric current and second electric current to the thermo-module in order to keep the temperature of the semiconductor laser at a predetermined value,
• the temperature control step including
• a calculation process for finding a maximum allowable first electric current to the thermo-module based on the temperature of the environment and the driving electric current to the semiconductor laser, the maximum allowable first electric current being an electric current with which the temperature of the semiconductor laser is kept at a predetermined maximum temperature or less even if continues to be supplied to the thermo-module, and
• a restriction process for restricting the first electric current to the thermo-module to the maximum allowable first electric current or less.