Yes. Under federal regulations, if an employer terminates an H-1B employee before the end of their period of authorized stay, the employer is liable for the reasonable costs of return transportation to the worker's last place of foreign residence. This does not apply if the worker resigns voluntarily. If an employer refuses to provide this, the worker may file a complaint with the Department of Labor (DOL) Wage and Hour Division.
A one-month gap is perfectly acceptable as long as you do not exceed the total allowable unemployment days. For the initial 12-month OPT, you are allowed 90 days of unemployment. If you transition to the 24-month STEM OPT extension, you receive an additional 60 days, for a total of 150 days over the entire period. Any unused days from the initial OPT period carry over into the STEM extension period.