hfss optical frequency

What do you need it for? HFSS is not generally well-suited for optical systems, and you can make plane wave excitations relatively easily depending on which version your license is.

Version 11.1.Please tell me step by step procedure

What is the purpose of it? Are you trying to model an optical system, or what? While HFSS is named "high frequency" structural simulator, you likely want to try something else for optics. Are you trying to excite a fiber, PBG system, planar waveguides, something else? Or what is the purpose of the laser?

I want to excite a fiber which is attached with the crystal.I am sending you an image

Added after 6 minutes:

image

It doesn't show up for me, just shows "image". Maybe try sending it by email/message or attaching it?

what's your email address

sorrow(score)harvester13(at)yahoo(dotcom)

Hopefully this way no bots will pick it up. Also perhaps attach the photo in this thread. I'm not that experienced with optical simulators, which it sounds like you may need. I've only used RSoft's Fullwave and only a little bit.

Okay just tell me how to excite a fiber with laser in HFSS

I recommend you don't use HFSS for this. HFSS is better suited for microwave/RF and not designed for optics. I haven't used it but MIT has free software called Meep that is (I think) FDTD and frequently used for optics. RSoft FullWAVE is also FDTD or eigenmode and suitable for optics.

Thanking you heaps

Added after 59 minutes:

Do you have any idea about simulator which can cover both optical and electrical domain

Any reasonable FDTD program should do. The only widely available commercial FDTD program I have
used - Quickwave - certainly should be capable. I can and do run both types of simulations with my own
FDTD program without any problems.