Patent ID: 7595510

Claim:
A laser diode module, comprising: a laser diode having anode and cathode electrodes, said laser diode emitting light by providing a driving signal with a primary frequency component in a gigahertz band to said anode electrode of said laser diode; a photodiode for monitoring said light emitted from said laser diode, said photodiode having anode and cathode electrodes, said photodiode being provided with a bias voltage in said anode electrode of said photodiode and providing a monitoring signal from said anode electrode of said photodiode; and a thin film resistor connected between a first lead terminal and said cathode electrode of said photodiode; a co-axial package including a cap and a stem for mounting said laser diode, said photodiode and said thin film resistor in a space formed by said cap and said stem, said stem including said first lead terminal commonly connected to said anode electrode of said laser diode and said cathode electrode of said photodiode through said thin film resistor, said driving signal being provided to said anode electrode of said laser diode and said cathode electrode of said photodiode through said first lead terminal, wherein said thin film resistor has resistance between 50 Ω and 3 kΩ to isolate said monitoring signal brought from said anode electrode of said photodiode, from said driving signal supplied to said cathode electrode of said photodiode.