Patent ID: 8548015

Claim:
A wavelength-tunable external cavity laser module comprising: a gain medium to which a bias current is applied; an optical waveguide combined with the gain medium and including a Bragg grating and a thin film heater adjusting a temperature of the Bragg grating; a high frequency transmission medium delivering a high frequency signal to the gain medium; and a package in which the gain medium and the optical waveguide are mounted, wherein the gain medium and the optical waveguide are directly combined with each other, wherein the high frequency transmission medium is disposed such that the high frequency signal delivered by the high frequency transmission medium is added to the bias current, the gain medium generates light corresponding to the bias current to which the high frequency signal has been added, and the high frequency transmission medium controls an operating speed of the light, wherein: a current value of the high frequency signal is controlled to modulate the optical power of the light into a digital signal; a frequency of the high frequency signal is set to let the digital signal have a bit rate of 10 Giga bit per second or greater; the high frequency transmission medium comprises a transmission line and a matching resistance unit, the matching resistance unit being disposed between the transmission line and the gain medium; and both of the transmission line and the matching resistance unit are disposed within the package.