Do you know if the module includes a current regulating driver? Do you have a picture of the module, or a link to it somewhere? This could help us identify its power requirements.
There's a 250mw laser diode on dtrs site. This picture shows the power output with 5.64v
Of course every diode is different to a certain degree so yours may be putting out more or less than 100mw
But yes we need to see where you're measuring and what you have so we can help you better.