I am just completing bright light therapy for PD at Mass general. I have seen improvement.
The full spectrum lights (seasonal affective disorder ) lights work well also.

so far i have not had any sleep problems, but i do get awfully tired sometimes.
about that lamp i do have one but got it from my Dr for depression and it was because we dont see the sun mch in the winter and by useing it everyday it was suposed to help .

I was determined not to take meds to improve my sleep. This morning when I woke up, while still laying in bed, I turned on my full spectrum light while doing my stretches. Within 20 minutes I am feeling more alert. I do think the light I used in the clinical trial (which was the red light) in combination was the most effective for improving my sleep. Talk to your health care provided.

I believe I am sleeping better and through the night since installing this Flux program on my computer that adjust the monitor light. I do not know the scientific reason for it. I think it is supposed to help with eye strain and circadian rhythms . I bring it up here so you can see if this adds any positive influence for PD patients that are on the computer. https://justgetflux.com/

I do still take naps during the day, but I also sleep at night. I do still have occasional jittery nights where I just cannot fall asleep until 4 AM or so. But i believe all and all I am sleeping better.

I found that I have to search specific words in this original question/comment.
First Word "Circadian dysregulation"
I found this page interesting. It is not PD specific, but has information on what is being researched in general.

And this about PD associated Circadian dysregulation. This is heavy reading.

https://www.sciencedirect.com/science/article/p...

http://www.greenmedinfo.com/disease/circadian-d...