| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To obtain a laser module suited to long-distance transmission and high-speed transmission at a low cost and a high output in a state where a load of a laser is low, signal distortion is small and there is no wavelength variation. <P>SOLUTION: A reflection type modulation module includes: a DFB laser for generating basic waveform light having a fixed wavelengthλn, fixed power and a fixed polarizing surface by a fixed injection current; a polarized-beam splitter for completely reflecting the basic waveform light and completely transmitting modulation light; a rotor for 45°-rotating the polarizing surfaces of the basic wavelength light and the modulation light; a reflection type modulation element having the same thin film structure as a Fabry-Perot laser and a front end face of a low reflectance R=0.01 to 0.3, arranged on a 45°obliquely twisted position so as to have the same polarizing surface as that of the basic waveform light, allowing an injection current to flow proportionally to an electric signal and changing an amplification factor to maintain and amplify the same frequencyλm as the basic waveform light passing the rotor, generating modulation light, and emitting the modulation light to the incident side; and an optical fiber on which the modulation light passed through the polarized beam splitter after rotating the polarizing surface by 45°is made incident. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
