Patent ID: 7072369

Claim:
A depolarized laser diode module comprising: a laser diode module having one laser diode and one polarization maintaining fiber which is connected to an output side of the laser diode and; a depolarizer connected to said laser diode module, wherein a length L Pig of the polarization maintaining fiber is a value obtained by calculation of equation 1 with use of a longitudinal mode spacing Δλ of output light from the laser diode which is greater than zero, an oscillating center wavelength λ 0 of the laser light which is greater than zero, a beat length L Beat 1 which is greater than zero of the polarization maintaining fiber which is greater than zero and an optical wavelength λ Beat used in a measurement of the beat length L Beat 1 . L Pig < λ 0 2 Δλ × L Beat ⁢ ⁢ 1 λ Beat ⁢ ⁢ 1 . ( Equation ⁢ ⁢ 1 )