The starting point of optical networking was the introduction of the optical amplifier in the early 1990’s. Amplifiers enabled both optical transport over longer distances and the ability to compensate for the losses in the optical Mux and Demux units that were needed to create multi-channel systems.

The first WDM systems were two-channel systems that used 1310nm and 1550nm wavelengths. Shortly afterwards came multi-channel systems that used the 1550nm region – where the fiber attenuation is lowest. These systems used temperature stabilized lasers to provide the needed channels count, Dense Wavelength Division Multiplexing (DWDM). Because of the high costs involved, DWDM was only economical for long-haul applications. Therefore, most optical systems vendors competed at providing the highest channel count and the longest distances.

The need for WDM solutions in the metro region became stronger and a new alternative technology emerged. Transmode was in the forefront in introducing a solution based on less expensive transmitters without temperature stabilization and where the wavelengths were more separated in the spectrum, Coarse Wavelength Division Multiplexing (CWDM). Another Transmode solution is based on a patented low-loss DWDM architecture on single-fiber configurations where the expensive optical amplifiers can be omitted.

Whilst CWDM and DWDM technologies are handled as separate solutions among other vendors, Transmode has evolved into providing a seamless integration of CWDM and DWDM solutions operating on single-fiber and/or fiber-pair configurations. This provides a better flexibility and scalability than competing solutions which are based on down-scaled, long-haul systems.