I need to design a High speed Pulse width modulated laser transmitter that can send both audio and video for my final project.

Transmitter side.
I currently am planning to use the following
a triangle wave form generator 20MHz.
a high speed comparator.
I am stuck with the laser driver and laser. I am unsure what to use.
driver needs to be able to support high switching frequency roughly 20MHz also laser is limited to around 650nm needs to be visible and 1mw in power.

Receiver side
I am using photodetector -transimpedance amplifier
and a 4th order butterworth filter with cutoff frequency of 4MHz
I think i would need two kinds of amplifiers after the filtering stage one for audio and one for video.

my budget is limited to a 100 pounds for the transmitter and receiver.
I would appreciate any suggestions you guys may give. especially with the laser and laser driver IC.

thanks