Yes, I have used optimisation during the conversion of the tflite model. The code used for the conversion is attached below:
converter = tf.lite.TFLiteConverter.from_keras_model(model)

converter.optimizations = [tf.lite.Optimize.DEFAULT]

tflite_model = converter.convert()

with open('model.tflite', 'wb') as f:

f.write(tflite_model)

Let me know if you want more information.