A WDM transmitter system, comprising: an optical bus including a port for outputting a combined modulated signal; a first laser for generating a first optical signal at a first optical wavelength (λ 1); a first tunable modulator configured to modulate said first optical signal with information carried by a first modulation signal to produce a first modulated light signal; a first filter multiplexer configured to add said first modulated light signal onto the optical bus; a second laser (3n0) for generating a second optical signal at a second optical wavelength (λ n); a second tunable modulator (3n1) configured to modulate said second optical signal with information carried by a second modulation signal to produce a second modulated light signal; and a second filter multiplexer (3n2) configured to add the said second modulated light signal onto the optical bus with the first modulated light signal to produce the combined modulated signal; characterized by the first tunable modulator being further configured to be tunable based on intensities of at least one of the first optical signal before the first tunable modulator or the first modulated light signal after the first tunable modulator; the second tunable modulator (3n1) being further configured to be tunable based on intensities of at least one of the second optical signal before the second tunable modulator (3n1) or the second modulated light signal after the second tunable modulator (3n1); a first signal splitter situated between said first laser and said first tunable modulator for tapping off a portion of the first optical signal; a first optical detector configured to receive the portion of the first optical signal for generating a first photo current; a second signal splitter situated between said first tunable modulator and said first filter multiplexer for tapping of a portion of the first modulated light signal; a second optical detector configured to receive the portion of the first modulated light signal for generating a second photo current; wherein the first tunable modulator is configured to be tuned until a first desired loss is achieved based on at least one of the first and second photo currents; a third optical detector configured to receive optical illumination of the first modulated light signal at a location beyond said first filter multiplexer; and a tuner configured for tuning the first filter multiplexer to minimize loss of the first modulated light signal based on the optical illumination received at the third optical detector. an optical bus including a port for outputting a combined modulated signal; a first laser for generating a first optical signal at a first optical wavelength (λ 1); a first tunable modulator configured to modulate said first optical signal with information carried by a first modulation signal to produce a first modulated light signal; a first filter multiplexer configured to add said first modulated light signal onto the optical bus; a second laser (3n0) for generating a second optical signal at a second optical wavelength (λ n); a second tunable modulator (3n1) configured to modulate said second optical signal with information carried by a second modulation signal to produce a second modulated light signal; and a second filter multiplexer (3n2) configured to add the said second modulated light signal onto the optical bus with the first modulated light signal to produce the combined modulated signal; characterized by the first tunable modulator being further configured to be tunable based on intensities of at least one of the first optical signal before the first tunable modulator or the first modulated light signal after the first tunable modulator; the second tunable modulator (3n1) being further configured to be tunable based on intensities of at least one of the second optical signal before the second tunable modulator (3n1) or the second modulated light signal after the second tunable modulator (3n1); a first signal splitter situated between said first laser and said first tunable modulator for tapping off a portion of the first optical signal; a first optical detector configured to receive the portion of the first optical signal for generating a first photo current; a second signal splitter situated between said first tunable modulator and said first filter multiplexer for tapping of a portion of the first modulated light signal; a second optical detector configured to receive the portion of the first modulated light signal for generating a second photo current; wherein the first tunable modulator is configured to be tuned until a first desired loss is achieved based on at least one of the first and second photo currents; a third optical detector configured to receive optical illumination of the first modulated light signal at a location beyond said first filter multiplexer; and a tuner configured for tuning the first filter multiplexer to minimize loss of the first modulated light signal based on the optical illumination received at the third optical detector.