I am making a design where I have to splice PM single mode fiber to graded index multimode fiber, can it be possible with generic splicers or need some specialized one. what parameters should be considered to make an acceptable splice.
Try to change the time or/and current of the splicing arc. In order to understand the effect, try to use an additional arc several times after the main arc (in the main MM programm), observing the level of the loss. Using this method you can try to decrease the loss level. If not - try to decrease the time or the current of the main arc.
If you generic splicers gives poor splice quality, high losses and its parameters cannot be changed, then I recommend trying to make splicing through a third intermediate fiber. The fiber parameters must be selected based on the optical parameters of the optical fibers that you splice: aperture, geometric dimensions... They should be somewhere in the middle))))). Of course, a more detailed answer can be given if you provided more specific data on fibers and splicer.