Light-transmitting module capable of responding a high-frequency over 10GHz

Abstract

The laser diode of the present invention is mounted on the heat sink made of insulating material such as aluminum nitride (AlN). On the heat sink, a metal film, evaporated gold film, is provided and the laser diode is mounted on the heat sink such that the anode electrode of the laser diode faces and is in contact with the metal film. The heat sink is mounted on the grounded metal member, thus the metal member, the heat sink and the metal film forms an capacitor. The bias for the laser diode is provided via the metal film, thereby stabilizing the bias supply even when the operational frequency for the laser diode is over 10 Gbps.

1 - 17 . (canceled) 
     
     
         18 . A light-transmitting module, comprising:
 a metal block;   a heat sink mounted on the metal block;   a laser diode provided on the heat sink, the laser diode emitting light to an optical fiber with an optical axis;   a driver mounted on the metal block, the driver modulating the laser diode by a modulating signal;   a substrate mounted on the metal block, the substrate providing a wiring pattern and ground patterns, the wiring pattern providing the modulation signal to the laser diode, the ground patterns putting the wiring pattern therebetween to form a signal conducting line whose frequency is over 10 GHz; and   a package with a box portion and a cylindrical portion, the metal block, the heat sink, the laser diode, the driver and the substrate being installed within the box portion and the optical fiber being secured in the cylindrical portion,   wherein the driver is mounted on the metal block just behind the laser diode and is surrounded by the substrate.   
     
     
         19 . The light-emitting module according to  claim 18 ,
 wherein the substrate surrounds the back and a side of the driver.   
     
     
         20 . The light-emitting module according to  claim 18 ,
 further including a plurality of die capacitors to de-couple a bias voltage supplied to the driver,   wherein at least one of the die capacitors is mounted on the substrate and at least one of the die capacitors is mounted on the metal block so as to put the driver therebetween.   
     
     
         21 . The light-emitting module according to  claim 18 ,
 wherein the heat sink includes an insulating material and an electrically conductive layer electrically connected to the driver,   wherein the laser diode is mounted on the electrically conductive layer such that one of its anode and cathode faces and is in contact to the electrically conductive layer, and the other of its anode and cathode is connected to the driver, and   wherein the metal block, the insulating material and an electrically conductive layer forms a parallel-pate capacitor whose capacitance is greater than 50 pF.   
     
     
         22 . The light-emitting module according to  claim 21 ,
 wherein the insulating material is aluminum nitride (AlN).   
     
     
         23 . The light-emitting module according to  claim 21 ,
 wherein the insulating material and the electrically conductive layer has an area of 0.5 mm square.   
     
     
         24 . The light-emitting module according to  claim 18 ,
 wherein the heat sink includes an electrically conductive block, an insulating layer provided on the electrically conductive block, and an electrically conductive layer connected to the driver,   wherein the laser diode is mounted on the electrically conductive layer such that one of its anode and cathode faces and is in contact to the electrically conductive layer, and the other of its anode and cathode is connected to the driver, and   wherein the electrically conductive block, the insulating material and the electrically conductive layer forms a parallel-plate capacitor whose capacitance is greater than 50 pF.   
     
     
         25 . The light-emitting module according to  claim 24 ,
 wherein the insulating layer is made of silicon oxide (SiO 2 ), silicon nitride (SiN) or silicon oxi-nitride (SiON).   
     
     
         26 . The light-emitting module according to  claim 25 ,
 wherein the insulating layer has an area of 0.5 mm square and a thickness of 100 nm.   
     
     
         27 . The light-emitting module according to  claim 25 ,
 wherein the electrically conductive block is made of silicon.   
     
     
         28 . The light-emitting module according to  claim 25 ,
 wherein the electrically conductive block is made of copper tungsten (CuW).