Title:
【発明の名称】光波長モニタ
Document Type and Number:
Japanese Patent JPH02500046
Kind Code:
A
Abstract:
A wavelength monitor (25) uses a diffraction grating (35) and a beam splitter (31). Light from a superluminescent diode (SLD) is supplied to the beam splitter (31) and is projected onto the grating (35). The grating is formed by holographically projecting a diffraction pattern onto a polished surface which is then photoetched, thereby creating a blazed diffraction grating corresponding to the projected pattern. The etched grating is used as a master, wherein the etched grating is coated with reflective material. The reflective material is then transferred to a prepared substrate that has an ultra-low thermal expansion coefficient to form a low cost replica diffraction grating. The grating (35) formed in this manner becomes a very stable and efficient dispersive element that forms a spectrum of the SLD output that is free of ghost images and accurately deproduces the spectral distribution. A pair of optical sensors (41, 42) detect an imbalance in reflected light, providing an indication of wavelength deviation.
Inventors:
Sichua, Richard Francis
Application Number:
JP50501887A
Publication Date:
January 11, 1990
Filing Date:
July 09, 1987
Export Citation:
Assignee:
Allied Corporation
International Classes:
G01C19/72; G01J3/18; G01J9/00; (IPC1-7): G01C19/72; G01J3/18
Attorney, Agent or Firm:
Masaki Yamakawa (2 outside)