Optical Wavelength Services Market by Bandwidth (Equal to 10 Gbps, 40 Gbps, 100 Gbps, and More Than 100 Gbps); By Interface (SONET, OTN, and Ethernet); By Organization Size (Small and Medium-Sized Enterprises, and Large Enterprises); By Application (Short Haul, Long Haul, and Metro); By Geography (North America, Asia-Pacific, Europe, South America, and RoW), Industry Trends, Estimation & Forecast, 2018 – 2026