Introduction to Optics Image Processing Lab.
Augmented reality head-up display (AR-HMD)
This research presents an optical see-through (OST) head-mounted display (HMD) based on a dihedral corner reflector array (DCRA) to give a wide field of view (FOV). Traditional OST-HMD is to employ a mirror with partial transmission, which would limit the FOV constraint. A DCRA is consists of multiple of mirror elements. It can produce an approximate real image at the position of the virtual image of the traditional plane mirror. Such a feature is applied to link the exit pupil of HMD lens and the human eye for wide FOV. A HMD lens with FOV ±30 degree is developed in this paper. We also investigate and construct the DCRA to project the exit pupil of the HMD into the human eye. An optical system with hybrid simulation modes combining the HMD lens, DCRA and eye model is developed to verify the proposal feasibility. The simulation results show that the eye can receive the display information in the wide FOV through this kind of the OST-HMD development.
The optimization of lens system
We apply and develop some optimization algorithms such as damped least square (DLS) and genetic algorithm (GA), and artificial intelligence (AI) etc., to improve the variety of aberrations. These algorithms have to be developed in the optical software macro like Code V, Zemax and LightTool. Recently, we develop some algorithms through Zemax application programming interface (API).
Lens design
So far the lens design in the Lab is interested in the zoom lens, the endoscope lens and head-mounted display (HMD). Liquid lens elements are employed to develop a compact zoom lens system. The targets of endoscope lenses are wide angle views or having 3D image. The lab also focuses on developing the HMD.
Prescribed illumination distribution design
A new method is developed to design one freeform surface for arbitrary illumination distribution. With two freeform surfaces, we can design a lens to make the arbitrary laser beam distribution with uniform and collimation at the same time.
Routing device (ROADM, OXC) for DWDM system
A pair cyclic NxN array waveguide gratings (AWGs) and multiple tunable fiber Bragg gratings (FBGs) is employed to realize a dense wavelength-division multiplex (DWDM) routing device with N/2 input and output signal groups. According to NxN AWG wavelength routing rule, each input and output port pair of AWG has N – 1 wavelength bandwidth free spectral range (FSR) shown in output port. Therefore, the multiple tunable FBGs can be used to reflect the wavelength signals into drop end or be tuned into the FSR to make the wavelength signals passing into output end directly. Tuning the central wavelength of FBG into FSR makes the wavelength signals passing into output end directly without any wavelength signals interfering. In order to realize multiple DWDM routing groups’ device, we effectively plan the FSR for NxN AWGs, which is to input N/2 groups wavelength signals into every two port pair of AWG. Using this way, the wavelength signals in N/2 groups would be demultiplexed into output port with two wavelength intervals. The tunable FBGs can be used to determine whether the wavelength signal is reflected or not. Since the wavelength signals are shown by two wavelengths interval, the central wavelength of FBG can be tuned into this zone to avoid interfering the wavelength signals when we want to implement the wavelength signal passing into output end directly. As a result, the proposed multiple groups DWDM wavelength routing device is a low cost and offers more flexibility service in dynamic DWDM network.
