Wavelength monitor integrated laser modules for 25-GHz-spacing tunable applications

Integration of 25-GHz-spacing wavelength monitors into industry standard butterfly laser modules are successfully achieved through the use of a unique optics. The 2-thermoelectric cooler (TEC) design enables independent temperature control of the laser diode and the wavelength monitor, hence eliminating the temperature dependence of the etalon as well as wavelength variation due to temperature variation and aging. As a result of the independent temperature control, narrowband tuning is easily achieved. Results from a series of thorough wavelength stability tests show that the wavelength variation of these laser modules are well within the ITU-T recommended requirement for 25-GHz channel-spacing dense wavelength-division multiplexing (DWDM) applications throughout 25 years of usage.