Abstract: A Peltier control circuit detects a temperature of a device combined with a Peltier device and controls a current flowing through the Peltier device so as to keep the temperature of the device at a predetermined value. The circuit has a temperature sensing section for detecting the temperature of a device, a comparing section for comparing a temperature detection value with a predetermined temperature reference value, a limiting section for providing a comparison output with the limitation of a current flowing through the Peltier device and providing the limitation with a predetermined temperature characteristics, and a driving section for providing the Peltier device with an input or output driving current in accordance with the comparison output via the limiting section.

Abstract: A semiconductor laser module includes a semiconductor laser assembly formed by containing a semiconductor laser in a package, a lens assembly fixed by welding to the package of the semiconductor laser assembly, and a fiber assembly fixed by welding to the lens assembly. The semiconductor laser assembly includes a base fixed to the package and a carrier fixed to the base. The semiconductor laser is mounted on the carrier. A lens holder of the lens assembly is spot-welded to the package at a plurality of positions set below the upper surface of the base.

Abstract: A Peltier control circuit detects a temperature of a device combined with a Peltier device and controls a current flowing through the Peltier device so as to keep the temperature of the device at a predetermined value. The circuit has a temperature sensing section for detecting the temperature of a device, a comparing section for comparing a temperature detection value with a predetermined temperature reference value, a limiting section for providing a comparison output with the limitation of a current flowing through the Peltier device and providing the limitation with a predetermined temperature characteristics, and a driving section for providing the Peltier device with an input or output driving current in accordance with the comparison output via the limiting section.

Abstract: A laser diode assembly capable of controlling a temperature of a laser diode chip with a high accuracy. A Peltier device is mounted on a base member, and a carrier is mounted on the Peltier device. On the carrier are mounted the laser diode chip, a thermistor, and a relay block. A terminal for connecting the thermistor to an external circuit is provided so as to extend through the base member. The thermistor and the relay block are connected together by wire bonding, and the relay block and the terminal are also connected together by wire bonding. The laser diode assembly further includes a control circuit for controlling a driving current for the Peltier device contacting with the carrier so as to maintain a resistance of the thermistor fixed on the carrier at a constant value.

Abstract: A rod lens fixing method which can prevent the generation of cracks in a rod lens due to annealing to be carried out after welding a lens assembly. The rod lens fixing method includes the steps of providing a flanged split sleeve having an axial slit extending continuously from one end of the flanged split sleeve to the other end thereof, the axial slit being wide enough at least a flange of the flanged split sleeve to permit laser welding; press-fitting the rod lens into the flanged split sleeve; and applying a solder into the axial slit to solder the rod lens to the flange split sleeve. This method further includes the steps of inserting the flanged split sleeve into a bore formed at one end portion of a sleeve, the bore having a diameter larger than an outer diameter of the flanged split sleeve and smaller than an outer diameter of the flange; and laser-welding the flange to one end surface of the sleeve at a plurality of points on an outer circumference of the flange and in the axial slit.