H1B Validity after to come back to US after stint outside US

[karthiksankar]

I am currently employed in US on H1B. Here are the details of my passport and visa:

H1B Issued Date: 16th December, 2015
H1B Expiry Date: 18th August, 2018
Passport Expiry Date: 27th January, 2019

I am in my second year of H1B. However, I am getting an opportunity to work outside US for some years.

I would like to know the following (Assume I have a US employer interested in giving me an offer sometime in the future)

1. Till what date can I come back to the US on my current H1B without need for lottery or stamping? (Assume I have a US employer interested in giving me an offer)
2. Considering that my 6-year H1B term will end only in 2021, can I come back to US without lottery any time before 2021? My current visa is only till 2018, and I do not have a 3-year extension as of now.
3. Will my passport expiry date impact my ability to come back to US on H1B without lottery?
4. If I work for four or more years outside US (beyond 2021), can I come back to US on H1B without going through lottery?

Thanks,
Karthik

[scientist2016]

(1) Your current H1 expires in 2018; so that is the date until which you can enter without the need for stamping. However, if you change employers, you might have problems at POE, if you do not have documentation (like H1 amendment accepted by the USCIS, etc.).
(2) Yes you are cap exempt within the next 6 yrs.
(3) Nope. Your passport has got nothing to do with H1. All you need as an unexpired passport.
(4) Yes. See answer for 2 above.