A fully dry optical fiber cable can make the cable manufacturing processes more environmental friendly;and can connect to facility easily installation.In this paper

a new fully dry optical fiber cable was introduced

which used co-extrusion technology for doublelayer loose tube.The soft polypropylene（PP） material was used as the loose tube.The inner layer of loose tube was made up of PP to protect the optical fiber

for its soft characteristic.The outer layer consisted of a mixture of PP and low density linear polyethylene（PE-LLD） with a certain ratio.The production condition was optimized by analyzing the properties of the PP（or mixture of PP and PE）

the processed parameters and the different type of color master batch.It found that the double-layer composite loose tube possess better stability for excess fiber length and physical

mechanical properties

comparing with ordinary one.