The operating steps of free space acousto-optic modulator

The operating steps of free space acousto-optic modulator
The free space acousto-optic modulator inputs and outputs light beams through open light holes, requiring precise alignment and Bragg angle adjustment with a three-dimensional adjustment frame. Compared with the fiber coupling series, the free space series requires additional optical path adjustment steps, but has advantages such as flexible optical paths and intuitive observation of diffraction spots.

1. Universal installation and adjustment steps for free space acousto-optic modulator series
The installation and adjustment of the free space acousto-optic modulator are common operating steps for two models, as follows:
Step 1: After all external devices and circuits are connected, fix the acousto-optic device on the three-dimensional adjustment frame, adjust the height of the acousto-optic device up and down to allow the laser beam to pass through the optimal position of the acousto-optic device. Note: The optimal lighting position is in the middle of the crystal thickness, and 1.5mm away from the gold electrode before and after pressing.
Step 2: Turn on the 24V power supply and load the signal (it is recommended to keep the signal at 5V when debugging the diffraction intensity, so that the driving power supply can continue to work). Adjust the Bragg angle of the acousto-optic device left and right to achieve the highest first-order diffraction intensity.
Step 3: After adjusting the first order diffraction light of the acousto-optic device, any signal can be loaded according to the testing requirements.
2 0~5V type (free space)
2.1 Modulation Signal Description
The “0-5V” port is used to load control signals and is an analog signal of 0-5V. Turn off when the input voltage is 0V, and the RF output power reaches its maximum when the input voltage is 5V. The modulation method of this model is basically the same as the fiber coupled “0-5V analog type”, but the optical path structure is different, requiring additional installation and adjustment steps.
2.2 Connection method
The “RF” of the driving power supply is the RF power output port. Please connect it with the matching BNC signal line, and the other end of the signal line should be directly connected to the sound and light device with BNC. Note that this model uses BNC interface, which is different from the SMA interface of most fiber coupling models.
2.3 Power regulation
Please use a Phillips screwdriver to rotate the small hole knob on the side. The clockwise rotation power increases, while the counterclockwise rotation power decreases. Please note that the power adjustment knob of this model is located at a small hole on the side, which is different from the “amplitude modulation” port of other models.
3 High level conductive type (free space)
3.1 Modulation Signal Description
The ‘modulation’ port is used to load control signals and is a standard TTL digital signal. The power supply is conducting at a high level, and a 5V voltage must be applied to the “modulation” terminal to produce RF power output. When the modulation terminal is at a low level, the RF output is turned off. The modulation characteristics of this model are the same as the “high-level conduction type” of fiber coupling, but the optical path structure is different, requiring additional installation and adjustment steps. Note: The power supply is conducting at a high level, and a 5V voltage must be applied at the “modulation” end to produce RF power output.
3.2 Power regulation
Please use a Phillips screwdriver to rotate the small hole knob inside the “amplitude modulation” end. The clockwise rotation power increases, while the counterclockwise rotation power decreases. Note that the power adjustment direction of this model is opposite to the high-level conduction type of fiber coupling!