Semiconductor laser module, and method for driving the semiconductor laser module

A method for driving a semiconductor laser module having a semiconductor laser element, and a thermo-module for adjusting the temperature of the semiconductor laser element comprising the steps of:

• thermally connecting said thermo-module to said semiconductor laser element;
• adjusting the temperature of the semiconductor laser element in dependence upon an amount of current flowing into the thermo-module;
• and
• suppressing some of an overcurrent flowing into the thermo-module by providing an overcurrent flow limiting circuit for the thermo-module.

A transmission device comprising:

• an optical module having an optical element a characteristic of which is influenced by heat;
• a thermo-module for variably adjusting the temperature of the optical element in dependence upon an amount of a current flowing into said thermo-module;
• and
• at least one of an overcurrent limiting circuit which suppresses an overcurrent from flowing into said thermo-module and an overvoltage limiting circuit which suppresses overvoltage from being applied to said thermo-module is provided.

A thermo-module for variably controlling a temperature of an object in dependence upon an amount of a current supplied thereto comprising:

• a first substrate;
• a second substrate;
• a plurality of Peltier elements between the first and second substrate;
• and
• an overcurrent limiting circuit,
• wherein the first substrate is extended relative to the second substrate and wherein the overcurrent limiting circuit is disposed on the extended portion of the first substrate.