**6. References**

Barbastathis, G. & Psaltis, D., (2000). Volume holographic multiplexing methods, In: *Holographic data storage*, Coufal, H.J., Psaltis, D., & Sincerbox, G.T., pp. 21-62, Springer, 978-3540666912, New York.

**Part 3** 

**Holographic Devices** 


**Part 3** 

**Holographic Devices** 

254 Holograms – Recording Materials and Applications

Champagne, E.B. (1967). Nonparaxial imaging magnification and aberration properties in holography. *Journal of the Optical Society of America*, Vol. 57, No. 1, pp.51-55 Curtis, K., Pu, A., & Psaltis, D. (1994). Method for holographic storage using peristrophic

Fujimura, R., Shimura, T., & Kuroda, K. (2007). Polychromatic reconstruction for volume

Fujimura, R., Shimura, T., & Kuroda, K. (2010). Multiplexing capability in polychromatic

Gulanyan, E.K., Dorosh, I.R., Iskin, V.D., Mikaelyan, A.L., & Maiorchuk, M.A. (1979).

Külich, H.C. (1987). A new approach to read volume holograms at different wavelengths.

Petrov, M.P., Stepanov, S.I., & Kamshilin, A.A. (1979). Holographic storage of information

van Heerden, P.J. (1963). Theory of optical information storage in solids. *Applied Optics*, Vol.

reconstruction with selective detection method. *Optics Express*, Vol. 18, No. 2,

Nondestructive readout of holograms in iron-doped lithium niobate crystals. *Soviet* 

and peculiarities of light diffraction in birefringent electro-optic crystals. *Optics and* 

holographic memory. *Optics Letters*, Vol. 32, No. 13, pp.1860-1862

multiplexing. *Optics Letters*, Vol. 19, No. 13, pp.993-994

*Journal of Quantum Electronics*, Vol. 9, No. 5, pp.647-649

*Optics Communications*, Vol. 64, No. 5, pp.407-411

*Laser Technology*, Vol. 11, No. 3, pp.149-151

pp.1091-1098

2, No. 4, pp.393-400

**11** 

*Spain* 

**Application of Holograms in WDM Components** 

Coarse Wavelength Division Multiplexing (CWDM) technologies are being widely deployed internationally in metropolitan and access networks due to the increased demand for delivering more bandwidth to the subscriber, created by the need of enhanced services, (Koonen, 2006). For metro, and mainly for access networks applications, an increment in capacity may be achieved with a cost-effective multiplexing technology without the need for the high channel counts and closely spaced wavelengths typically used in long haul networks. A channel space of 20 nm, as proposed in the G. 694.2 ITU Rec., can be used relaxing the processing tolerances and potentially lowering the cost of components. CWDM technology reaches those requirements and it has been proposed for these applications. It is

This chapter describes the theory, design, and experimental results of a generic multipurpose device that can operate as a tunable wavelength filter, wavelength multiplexer and wavelength router. This device could be especially useful in optical network applications based on both Coarse and Dense Wavelength Division Multiplexing technology (CWDM/DWDM). The enabling component is a Ferro-electric Liquid Crystal (FLC) Spatial Light Modulator (SLM) in which dynamic holograms are implemented in real time. As a consequence, the device will be able to carry out different functions according to the hologram recorded on the SLM. The great advantage of this device is polarization insensitivity in the region of operation, allowing low cross-talk and simple handling. As hologram management is the basis for this device, some topics in the Computer Generated Hologram (CGH) design

Laboratory experiments have demonstrated the capability of a phase FLC-SLM, with the great advantage of polarization insensitivity operation, to diffract the incident light according its wavelength and hologram patterns, for the use in the former applications. Two typical applications of this technology are described: the first one is a design of an equalized holographic Reconfigurable Optical Add-Drop Multiplexer ( ROADM), where this device can address several wavelengths at the input to different output fibers, according to the holograms stored in a SLM (Spatial Light Modulator), all the outputs being equalized in power; the second one is dealing with the design of an holographic router with loss compensation and wavelength conversion whose main application is in Metro networks in the interconnection nodes. This device uses a SOA (Semiconductor Optical Amplifier), in the non linear region, to do the wavelength conversion and, in addition, to supply the gain in

in this context that holographic optical devices have a potential use.

process are commented on and general guidelines are also considered.

order to compensate for the intrinsic losses of the holographic device.

**1. Introduction** 

**for Optical Fiber Systems** 

*ETSIT-Universidad Politécnica de Madrid* 

Alfredo Martín Mínguez and Paloma R. Horche
