If your employer provided you with a  signed T2200S then yes. You will choose the detailed rate method - Then you will see below- Electricity, heat, water, home internet access fees- This is where you will claim  your internet expenses. 

If you did not receive a signed T2200S you will need to use the flat rate method. The flat rate method is simple and straightforward. You can claim $2 for each day that you worked at home, up to a maximum of $500.00. There's no requirement to provide supporting documents.