Based on our custom fiber coupler working station, we can make all kinds of larger core size fiber coupler, which fiber ranges from 105/125um, 220/220um, 400/440um, even to 600/660um. This kind of fused coupler is widely used in fiber laser developing, quantum imaging and medical photonics, optical communication and etc.
As generally we can make these fused components which insertion loss is less than 1.5dB. Its configuration is 1x2 or 2x2.
We would like to offer this customer device on request of this different fiber.