Abstract: An optical transmission system and method may control optical signal transmission in an optical network, such as a passive optical network (PON), to reduce degradation of one or more optical signals traveling over the same optical waveguide. In particular, optical signal transmission may be controlled to reduce carrier to noise ratio (CNR) degradation of an optical signal (e.g., a multichannel video signal) resulting from the effects of stimulated Raman scattering (SRS) and/or double Rayleigh backscattering (DRBS). The CNR degradation may be reduced by controlling transmission of one or more of a plurality of optical signals in the optical network based on various parameters affecting the contribution to CNR degradation by SRS and/or DRBS and affecting the performance of the optical transmission system. The optical signal transmission may be controlled by adjusting a preemphasis and/or transmitted power of the optical signal(s).

Abstract: A wavelength-tunable distributed feedback (DFB) laser is disclosed where the lasing wavelength can be adjusted by adjusting the bias current of the laser diode. Since the output power of the laser diode also changes with the bias current, a one-to-one correspondence between the lasing wavelength and the output power of the laser can be established. Consequently, the lasing wavelength can be measured directly from the photocurrent of a power monitoring detector facing the back-end of the laser diode. This provides an extremely simple method for wavelength monitoring.

Abstract: A wavelength-tunable distributed feedback (DFB) laser is disclosed where the lasing wavelength can be adjusted by adjusting the bias current of the laser diode. Since the output power of the laser diode also changes with the bias current, a one-to-one correspondence between the lasing wavelength and the output power of the laser can be established. Consequently, the lasing wavelength can be measured directly from the photocurrent of a power monitoring detector facing the back-end of the laser diode. This provides an extremely simple method for wavelength monitoring.