OUR EXPERTISE

The journey of seeking for low-cost tunable source began with developing the thermally tunable polymer waveguide filter by Dr. Kim in 2003 when he was in ETRI (Electronics and Telecommunications Research Institute of South Korea). Since then, this type of technology has been continuously interested by a Korean company, and later by a German research institute. According to our experience, however, the polymer type showed some drawbacks including reliability issues to maintain a wavelength after a long-term heating, which in turn significantly limits the tuning range.

           Another attempt started with mechanically tunable fiber Bragg filter in 2012. This type, on one hand, provides a fascinating advantage from a low-cost perspective, which can be lowered under $100 depending on production volumes. However, on the other hand, it provides a difficulty in increasing the data rate beyond 2.5 Gbps due to its long external cavity length.

           The electrically tunable liquid crystal filter is our third attempt and shows a variety of advantages including reliability, high- speed data rate, large enough tuning range, and foremost of all, the chance of lowering cost way down under those of currently available tunable sources. This type, we call LET (Liquid crystal Electrically Tunable), has been our focus since 2014.