Analog Video Transmission Research Articles

Intensity noise of semiconductor laser diodes in fiber optic analog video transmission

This paper presents an investigation of the effects of laser diode noise on analog video transmission in the HF and VHF bands, which resulted in the development of several designs of graded-index multimode fiber systems that can ignore reflection induced laser noise. The contents of the investigation include: 1) The evaluation of intrinsic laser noise of various laser structures and the evaluation of modulation effects on laser diode noise characteristics. It was found that the relative intensity noise (RIN) is less than -145 ∼ -150 [dB/Hz] when the modulation factor is less than 0.7 for index-guide mode stabilized lasers; 2) The quantitative evaluation of reflected laser beam effects on laser noise characteristics. The maximum laser-coupled reflected optical power that does not increase laser noise was determined as-65 ∼ -73 dB or less depending on the kind of laser structure; and 3) The evaluation of optical power reflected back into the laser in graded-index multimode fiber systems.

Speckle Noise Reduction in Fiber Optic Analog Video Transmission Using Semiconductor Laser Diodes

This paper investigates the effects of speckle noise on analog video transmission systems using semiconductor laser diodes. The system linearity degradation due to speckle noise is examined using different fiber types. Then this paper proposes a new modulation technique employing a superimposed pulse scheme to reduce speckle noise. It is experimentally confirmed that the proposed modulation method is effective in reducing speckle noise. Based on the above investigations, analog video transmission experiments are performed using single-mode fibers, step-index multimode fibers, and graded-index multimode fibers in the 0.8 and 1.3 μm wavelength regions. The results of the transmission tests have confirmed the feasibility of analog video transmission using semiconductor laser diodes.

Superimposed pulse modulation for fibre optic analogue video transmission using semiconductor laser diodes

The letter proposes a new modulation technique to reduce speckle noise in multimode optical fibre analogue transmission systems using semiconductor laser diodes. The feasibility of analogue video transmission systems using the proposed modulation technique has been confirmed.